diff --git a/cmake/version.inc b/cmake/version.inc
index 8c02520142..ad399bfa86 100644
--- a/cmake/version.inc
+++ b/cmake/version.inc
@@ -1,42 +1,65 @@
 CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 PROJECT(TDengine)
 
-SET(TD_VER_1 "2")
-SET(TD_VER_2 "0")
-SET(TD_VER_3 "2")
-SET(TD_VER_4 "3")
-SET(TD_VER_GIT "d711657139620f6c50f362597020705b8ad26bd2")
-SET(TD_VER_GIT_INTERNAL "1d74ae24c541ffbb280e8630883c0236cd45f8c7")
+IF (DEFINED VERNUMBER)
+  SET(TD_VER_NUMBER ${VERNUMBER})
+ELSE ()
+  SET(TD_VER_NUMBER "2.0.2.0")
+ENDIF ()
 
-SET(TD_VER_VERTYPE "stable")
-SET(TD_VER_CPUTYPE "x64")
-SET(TD_VER_OSTYPE  "Linux")
+IF (DEFINED VERCOMPATIBLE)
+  SET(TD_VER_COMPATIBLE ${VERCOMPATIBLE})
+ELSE ()
+  SET(TD_VER_COMPATIBLE "2.0.0.0")
+ENDIF ()
 
-SET(TD_VER_COMPATIBLE "2.0.0.0")
-STRING(TIMESTAMP TD_VER_DATE "%Y-%m-%d %H:%M:%S") 
+IF (DEFINED GITINFO)
+  SET(TD_VER_GIT ${GITINFO})
+ELSE ()
+  SET(TD_VER_GIT "community")
+ENDIF ()
 
-IF (TD_LINUX_64)
+IF (DEFINED GITINFOI)
+  SET(TD_VER_GIT_INTERNAL ${GITINFOI})
+ELSE ()
+  SET(TD_VER_GIT_INTERNAL "internal")
+ENDIF ()
+
+IF (DEFINED VERDATE)
+  SET(TD_VER_DATE ${VERDATE})
+ELSE ()
+  STRING(TIMESTAMP TD_VER_DATE "%Y-%m-%d %H:%M:%S") 
+ENDIF ()
+
+IF (DEFINED VERTYPE)
+  SET(TD_VER_VERTYPE ${VERTYPE})
+ELSE ()
+  SET(TD_VER_VERTYPE "stable")
+ENDIF ()
+
+IF (DEFINED CPUTYPE)
+  SET(TD_VER_CPUTYPE ${CPUTYPE})
+ELSE ()
   SET(TD_VER_CPUTYPE "x64")
 ENDIF ()
 
-IF (TD_LINUX_32)
-  SET(TD_VER_CPUTYPE "x86")
+IF (DEFINED OSTYPE)
+  SET(TD_VER_OSTYPE ${OSTYPE})
+ELSE ()
+  SET(TD_VER_OSTYPE "Linux")
 ENDIF ()
 
-IF (TD_ARM_64)
-  SET(TD_VER_CPUTYPE "aarch64")
-ENDIF ()
+MESSAGE(STATUS "============= compile version parameter information start ============= ")
+MESSAGE(STATUS "ver number:" ${TD_VER_NUMBER})
+MESSAGE(STATUS "compatible ver number:" ${TD_VER_COMPATIBLE})
+MESSAGE(STATUS "communit commit id:" ${TD_VER_GIT})
+MESSAGE(STATUS "internal commit id:" ${TD_VER_GIT_INTERNAL})
+MESSAGE(STATUS "build date:" ${TD_VER_DATE})
+MESSAGE(STATUS "ver type:" ${TD_VER_VERTYPE})
+MESSAGE(STATUS "ver cpu:" ${TD_VER_CPUTYPE})
+MESSAGE(STATUS "os type:" ${TD_VER_OSTYPE})
+MESSAGE(STATUS "============= compile version parameter information end  ============= ")
 
-IF (TD_ARM_32)
-  SET(TD_VER_CPUTYPE "aarch32")
-ENDIF ()
-  
-IF (TD_WINDOWS_64)
-  SET(TD_VER_CPUTYPE "x64")
-ENDIF ()
-
-IF (TD_WINDOWS_32)
-  SET(TD_VER_CPUTYPE "x86")
-ENDIF ()
+STRING(REPLACE "." "_" TD_LIB_VER_NUMBER ${TD_VER_NUMBER})
 
 CONFIGURE_FILE("${TD_COMMUNITY_DIR}/src/util/src/version.c.in" "${TD_COMMUNITY_DIR}/src/util/src/version.c")
diff --git a/documentation20/webdocs/markdowndocs/administrator-ch.md b/documentation20/webdocs/markdowndocs/administrator-ch.md
index c5ecb862e3..64cadf69cd 100644
--- a/documentation20/webdocs/markdowndocs/administrator-ch.md
+++ b/documentation20/webdocs/markdowndocs/administrator-ch.md
@@ -153,10 +153,10 @@ TDengine系统的前台交互客户端应用程序为taos，它与taosd共享同
 系统管理员可以在CLI界面里添加、删除用户，也可以修改密码。CLI里SQL语法如下：
 
 ```
-CREATE USER <user_name> PASS <‘password’>;
+CREATE USER <user_name> PASS <'password'>;
 ```
 
-创建用户，并指定用户名和密码，密码需要用单引号引起来
+创建用户，并指定用户名和密码，密码需要用单引号引起来,单引号为英文半角
 
 ```
 DROP USER <user_name>;
@@ -165,10 +165,10 @@ DROP USER <user_name>;
 删除用户，限root用户使用
 
 ```
-ALTER USER <user_name> PASS <‘password’>;
+ALTER USER <user_name> PASS <'password'>;
 ```
 
-修改用户密码, 为避免被转换为小写，密码需要用单引号引用
+修改用户密码, 为避免被转换为小写，密码需要用单引号引用,单引号为英文半角
 
 ```
 SHOW USERS;
diff --git a/documentation20/webdocs/markdowndocs/architecture-ch.md b/documentation20/webdocs/markdowndocs/architecture-ch.md
index bfe3b55bd2..7ab4b5d096 100644
--- a/documentation20/webdocs/markdowndocs/architecture-ch.md
+++ b/documentation20/webdocs/markdowndocs/architecture-ch.md
@@ -82,7 +82,7 @@ TDengine 分布式架构的逻辑结构图如下：
 ### 节点之间的通讯
 **通讯方式：**TDengine系统的各个节点之间的通讯是通过TCP/UDP进行的。因为考虑到物联网场景，数据写入的包一般不大，因此TDengine 除采用TCP做传输之外，还采用UDP方式，因为UDP 更加高效，而且不受连接数的限制。TDengine实现了自己的超时、重传、确认等机制，以确保UDP的可靠传输。对于数据量不到15K的数据包，采取UDP的方式进行传输，超过15K的，或者是查询类的操作，自动采取TCP的方式进行传输。同时，TDengine根据配置和数据包，会自动对数据进行压缩/解压缩，数字签名/认证等处理。对于数据节点之间的数据复制，只采用TCP方式进行数据传输。
 
-**FQDN配置**：一个数据节点有一个或多个FQDN，可以在系统配置文件taos.cfg通过选项“fqdn"进行指定，如果没有指定，系统将自动获取FQDN。如果节点没有配置FQDN，可以直接使用IP地址作为FQDN，但不建议使用，因为IP地址可变，一旦变化，将让集群无法正常工作。一个数据节点的EP(End Point)由FQDN + Port组成。
+**FQDN配置**：一个数据节点有一个或多个FQDN，可以在系统配置文件taos.cfg通过参数“fqdn"进行指定，如果没有指定，系统将自动获取FQDN。如果节点没有配置FQDN，可以直接将该节点的配置参数fqdn设置为它的IP地址。但不建议使用IP，因为IP地址可变，一旦变化，将让集群无法正常工作。一个数据节点的EP(End Point)由FQDN + Port组成。采用FQDN，需要保证DNS服务正常工作，或者在节点以及应用所在的节点配置好hosts文件。
 
 **端口配置：**一个数据节点对外的端口由TDengine的系统配置参数serverPort决定，对集群内部通讯的端口是serverPort+5。集群内数据节点之间的数据复制操作还占有一个TCP端口，是serverPort+10. 为支持多线程高效的处理UDP数据，每个对内和对外的UDP链接，都需要占用5个连续的端口。因此一个数据节点总的端口范围为serverPort到serverPort + 10，总共11个TCP/UDP端口。使用时，需要确保防火墙将这些端口打开。每个数据节点可以配置不同的serverPort。
 
diff --git a/packaging/release.sh b/packaging/release.sh
index bf355bdcd4..3c0378042d 100755
--- a/packaging/release.sh
+++ b/packaging/release.sh
@@ -12,6 +12,7 @@ set -e
 #             -l [full | lite]
 #             -s [static | dynamic]
 #             -n [2.0.0.3]
+#             -m [2.0.0.0]
 
 # set parameters by default value
 verMode=edge     # [cluster, edge]
@@ -21,8 +22,9 @@ osType=Linux     # [Linux | Kylin | Alpine | Raspberrypi | Darwin | Windows | Ni
 pagMode=full     # [full | lite]
 soMode=dynamic   # [static | dynamic]
 verNumber=""
+verNumberComp="2.0.0.0"
 
-while getopts "hv:V:c:o:l:s:n:" arg
+while getopts "hv:V:c:o:l:s:n:m:" arg
 do
   case $arg in
     v)
@@ -49,6 +51,10 @@ do
       #echo "verNumber=$OPTARG"
       verNumber=$(echo $OPTARG)
       ;;
+    m)
+      #echo "verNumberComp=$OPTARG"
+      verNumberComp=$(echo $OPTARG)
+      ;;
     o)
       #echo "osType=$OPTARG"
       osType=$(echo $OPTARG)
@@ -61,6 +67,7 @@ do
       echo "                  -l [full | lite] "
       echo "                  -s [static | dynamic] "
       echo "                  -n [version number] "
+      echo "                  -m [compatible version number] "
       exit 0
       ;;
     ?) #unknow option 
@@ -70,216 +77,142 @@ do
   esac
 done
 
-echo "verMode=${verMode} verType=${verType} cpuType=${cpuType} osType=${osType} pagMode=${pagMode} soMode=${soMode} verNumber=${verNumber}"
+echo "verMode=${verMode} verType=${verType} cpuType=${cpuType} osType=${osType} pagMode=${pagMode} soMode=${soMode} verNumber=${verNumber} verNumberComp=${verNumberComp}"
 
 curr_dir=$(pwd)
 
 if [ "$osType" != "Darwin" ]; then
-    script_dir="$(dirname $(readlink -f $0))"
-    top_dir="$(readlink -f ${script_dir}/..)"
+  script_dir="$(dirname $(readlink -f $0))"
+  top_dir="$(readlink -f ${script_dir}/..)"
 else
-    script_dir=`dirname $0`
-    cd ${script_dir}
-    script_dir="$(pwd)"
-    top_dir=${script_dir}/..
+  script_dir=`dirname $0`
+  cd ${script_dir}
+  script_dir="$(pwd)"
+  top_dir=${script_dir}/..
 fi
 
-versioninfo="${top_dir}/src/util/src/version.c"
-
 csudo=""
 #if command -v sudo > /dev/null; then
-#    csudo="sudo"
+#  csudo="sudo"
 #fi
 
 function is_valid_version() {
-    [ -z $1 ] && return 1 || :
+  [ -z $1 ] && return 1 || :
 
-    rx='^([0-9]+\.){3}(\*|[0-9]+)$'
-    if [[ $1 =~ $rx ]]; then
-        return 0
-    fi
-    return 1
+  rx='^([0-9]+\.){3}(\*|[0-9]+)$'
+  if [[ $1 =~ $rx ]]; then
+    return 0
+  fi
+  return 1
 }
 
 function vercomp () {
-    if [[ $1 == $2 ]]; then
-        echo 0
-        exit 0
-    fi
-    
-    local IFS=.
-    local i ver1=($1) ver2=($2)
-
-    # fill empty fields in ver1 with zeros
-    for ((i=${#ver1[@]}; i<${#ver2[@]}; i++)); do
-        ver1[i]=0
-    done
-
-    for ((i=0; i<${#ver1[@]}; i++)); do
-        if [[ -z ${ver2[i]} ]]; then
-            # fill empty fields in ver2 with zeros
-            ver2[i]=0
-        fi
-        if ((10#${ver1[i]} > 10#${ver2[i]})); then
-            echo 1
-            exit 0
-        fi
-        if ((10#${ver1[i]} < 10#${ver2[i]})); then
-            echo 2
-            exit 0
-        fi
-    done
+  if [[ $1 == $2 ]]; then
     echo 0
-}
+    exit 0
+  fi
+  
+  local IFS=.
+  local i ver1=($1) ver2=($2)
 
-# 1. Read version information
-version=$(cat ${versioninfo} | grep " version" | cut -d '"' -f2)
-compatible_version=$(cat ${versioninfo} | grep " compatible_version" | cut -d '"' -f2)
+  # fill empty fields in ver1 with zeros
+  for ((i=${#ver1[@]}; i<${#ver2[@]}; i++)); do
+    ver1[i]=0
+  done
 
-if [ -z ${verNumber} ]; then
-  while true; do
-    read -p "Do you want to release a new version? [y/N]: " is_version_change
-
-    if [[ ( "${is_version_change}" == "y") || ( "${is_version_change}" == "Y") ]]; then
-      read -p "Please enter the new version: " tversion
-      while true; do
-          if (! is_valid_version $tversion) || [ "$(vercomp $tversion $version)" = '2' ]; then
-              read -p "Please enter a correct version: " tversion
-              continue
-          fi
-          version=${tversion}
-          break
-      done
-
-      echo
-
-      read -p "Enter the oldest compatible version: " tversion
-      while true; do
-
-          if [ -z $tversion ]; then
-              break
-          fi
-
-          if (! is_valid_version $tversion) || [ "$(vercomp $version $tversion)" = '2' ]; then
-              read -p "enter correct compatible version: " tversion
-          else
-              compatible_version=$tversion
-              break
-          fi
-      done
-
-      break
-    elif [[ ( "${is_version_change}" == "n") || ( "${is_version_change}" == "N") ]]; then
-      echo "Use old version: ${version} compatible version: ${compatible_version}."
-      break
-    else
-      continue
+  for ((i=0; i<${#ver1[@]}; i++)); do
+    if [[ -z ${ver2[i]} ]]; then
+      # fill empty fields in ver2 with zeros
+      ver2[i]=0
+    fi
+    if ((10#${ver1[i]} > 10#${ver2[i]})); then
+      echo 1
+      exit 0
+    fi
+    if ((10#${ver1[i]} < 10#${ver2[i]})); then
+      echo 2
+      exit 0
     fi
   done
-else 
-  echo "old version: $version, new version: $verNumber"
-  #if ( ! is_valid_version $verNumber ) || [[ "$(vercomp $version $verNumber)" == '2' ]]; then
-  #  echo "please enter correct version"
-  #  exit 0
-  #else
-    version=${verNumber}
-  #fi  
-fi  
+  echo 0
+}
 
-echo "=======================new version number: ${version}======================================"
+# 1. check version information
+if (( ! is_valid_version $verNumber ) || ( ! is_valid_version $verNumberComp ) || [[ "$(vercomp $verNumber $verNumberComp)" == '2' ]]); then
+  echo "please enter correct version"
+  exit 0
+fi
+
+echo "=======================new version number: ${verNumber}, compatible version: ${verNumberComp}======================================"
 
-# output the version info to the buildinfo file.
 build_time=$(date +"%F %R")
-echo "char version[12] = \"${version}\";"                             > ${versioninfo}
-echo "char compatible_version[12] = \"${compatible_version}\";"      >> ${versioninfo}
-echo "char gitinfo[48] = \"$(git rev-parse --verify HEAD)\";"       >> ${versioninfo}
-if [ "$verMode" != "cluster" ]; then
-  echo "char gitinfoOfInternal[48] = \"\";"                         >> ${versioninfo}
-else
-  enterprise_dir="${top_dir}/../enterprise"
-  cd ${enterprise_dir}
-  echo "char gitinfoOfInternal[48] = \"$(git rev-parse --verify HEAD)\";"  >> ${versioninfo}
-  cd ${curr_dir}
-fi
-echo "char buildinfo[64] = \"Built by ${USER} at ${build_time}\";"  >> ${versioninfo}
-echo ""                                                              >> ${versioninfo}
-tmp_version=$(echo $version | tr -s "." "_")
-if [ "$verMode" == "cluster" ]; then
-  libtaos_info=${tmp_version}_${osType}_${cpuType}
-else
-  libtaos_info=edge_${tmp_version}_${osType}_${cpuType}
-fi
-if [ "$verType" == "beta" ]; then
-  libtaos_info=${libtaos_info}_${verType}
-fi
-echo "void libtaos_${libtaos_info}() {};"        >> ${versioninfo}
+
+# get commint id from git
+gitinfo=$(git rev-parse --verify HEAD)
+enterprise_dir="${top_dir}/../enterprise"
+cd ${enterprise_dir}
+gitinfoOfInternal=$(git rev-parse --verify HEAD)
+cd ${curr_dir}
 
 # 2. cmake executable file
 compile_dir="${top_dir}/debug"
 if [ -d ${compile_dir} ]; then
-    ${csudo} rm -rf ${compile_dir}
+  ${csudo} rm -rf ${compile_dir}
 fi
 
 if [ "$osType" != "Darwin" ]; then
-    ${csudo} mkdir -p ${compile_dir}
+  ${csudo} mkdir -p ${compile_dir}
 else
-    mkdir -p ${compile_dir}
+  mkdir -p ${compile_dir}
 fi
 cd ${compile_dir}
 
 # check support cpu type
 if [[ "$cpuType" == "x64" ]] || [[ "$cpuType" == "aarch64" ]] || [[ "$cpuType" == "aarch32" ]] || [[ "$cpuType" == "mips64" ]] ; then
-    if [ "$verMode" != "cluster" ]; then
-      cmake ../ -DCPUTYPE=${cpuType} -DPAGMODE=${pagMode} -DOSTYPE=${osType} -DSOMODE=${soMode}
-    else
-      cmake ../../ -DCPUTYPE=${cpuType} -DOSTYPE=${osType} -DSOMODE=${soMode} 
-    fi
+  if [ "$verMode" != "cluster" ]; then
+    cmake ../    -DCPUTYPE=${cpuType} -DOSTYPE=${osType} -DSOMODE=${soMode} -DVERTYPE=${verType} -DVERDATE="${build_time}" -DGITINFO=${gitinfo} -DGITINFOI=${gitinfoOfInternal} -DVERNUMBER=${verNumber} -DVERCOMPATIBLE=${verNumberComp} -DPAGMODE=${pagMode}
+  else
+    cmake ../../ -DCPUTYPE=${cpuType} -DOSTYPE=${osType} -DSOMODE=${soMode} -DVERTYPE=${verType} -DVERDATE="${build_time}" -DGITINFO=${gitinfo} -DGITINFOI=${gitinfoOfInternal} -DVERNUMBER=${verNumber} -DVERCOMPATIBLE=${verNumberComp}
+  fi
 else
-    echo "input cpuType=${cpuType} error!!!"
-    exit 1
+  echo "input cpuType=${cpuType} error!!!"
+  exit 1
 fi
 
 make
 
 cd ${curr_dir}
 
-# 3. judge the operating system type, then Call the corresponding script for packaging
-#osinfo=$(awk -F= '/^NAME/{print $2}' /etc/os-release)
-#osinfo=$(cat /etc/os-release | grep "NAME" | cut -d '"' -f2)
-#echo "osinfo: ${osinfo}"
-
+# 3. Call the corresponding script for packaging
 if [ "$osType" != "Darwin" ]; then
-    if [[ "$verMode" != "cluster" ]] && [[ "$cpuType" == "x64" ]]; then
-        echo "====do deb package for the ubuntu system===="
-        output_dir="${top_dir}/debs"
-        if [ -d ${output_dir} ]; then
-            ${csudo} rm -rf ${output_dir}
-        fi
-        ${csudo} mkdir -p ${output_dir}
-        cd ${script_dir}/deb
-        ${csudo} ./makedeb.sh ${compile_dir} ${output_dir} ${version} ${cpuType} ${osType} ${verMode} ${verType}
-
-        echo "====do rpm package for the centos system===="
-        output_dir="${top_dir}/rpms"
-        if [ -d ${output_dir} ]; then
-            ${csudo} rm -rf ${output_dir}
-        fi
-        ${csudo} mkdir -p ${output_dir}
-        cd ${script_dir}/rpm
-        ${csudo} ./makerpm.sh ${compile_dir} ${output_dir} ${version} ${cpuType} ${osType} ${verMode} ${verType}
+  if [[ "$verMode" != "cluster" ]] && [[ "$cpuType" == "x64" ]]; then
+    echo "====do deb package for the ubuntu system===="
+    output_dir="${top_dir}/debs"
+    if [ -d ${output_dir} ]; then
+      ${csudo} rm -rf ${output_dir}
     fi
+    ${csudo} mkdir -p ${output_dir}
+    cd ${script_dir}/deb
+    ${csudo} ./makedeb.sh ${compile_dir} ${output_dir} ${verNumber} ${cpuType} ${osType} ${verMode} ${verType}
+
+    echo "====do rpm package for the centos system===="
+    output_dir="${top_dir}/rpms"
+    if [ -d ${output_dir} ]; then
+      ${csudo} rm -rf ${output_dir}
+    fi
+    ${csudo} mkdir -p ${output_dir}
+    cd ${script_dir}/rpm
+    ${csudo} ./makerpm.sh ${compile_dir} ${output_dir} ${verNumber} ${cpuType} ${osType} ${verMode} ${verType}
+  fi
 	
-    echo "====do tar.gz package for all systems===="
-    cd ${script_dir}/tools
-    
-	${csudo} ./makepkg.sh    ${compile_dir} ${version} "${build_time}" ${cpuType} ${osType} ${verMode} ${verType} ${pagMode}
-	${csudo} ./makeclient.sh ${compile_dir} ${version} "${build_time}" ${cpuType} ${osType} ${verMode} ${verType} ${pagMode}
-	${csudo} ./makearbi.sh   ${compile_dir} ${version} "${build_time}" ${cpuType} ${osType} ${verMode} ${verType} ${pagMode}
+  echo "====do tar.gz package for all systems===="
+  cd ${script_dir}/tools
+  
+	${csudo} ./makepkg.sh    ${compile_dir} ${verNumber} "${build_time}" ${cpuType} ${osType} ${verMode} ${verType} ${pagMode}
+	${csudo} ./makeclient.sh ${compile_dir} ${verNumber} "${build_time}" ${cpuType} ${osType} ${verMode} ${verType} ${pagMode}
+	${csudo} ./makearbi.sh   ${compile_dir} ${verNumber} "${build_time}" ${cpuType} ${osType} ${verMode} ${verType} ${pagMode}
 else
-    cd ${script_dir}/tools
-    ./makeclient.sh ${compile_dir} ${version} "${build_time}" ${cpuType} ${osType} ${verMode} ${verType}
+  cd ${script_dir}/tools
+  ./makeclient.sh ${compile_dir} ${verNumber} "${build_time}" ${cpuType} ${osType} ${verMode} ${verType}
 fi
 
-# 4. Clean up temporary compile directories
-#${csudo} rm -rf ${compile_dir}
- 
diff --git a/packaging/tools/install.sh b/packaging/tools/install.sh
index f38677f7ac..1cbb3ead9c 100755
--- a/packaging/tools/install.sh
+++ b/packaging/tools/install.sh
@@ -705,6 +705,7 @@ function install_TDengine() {
         echo
         echo -e "\033[44;32;1mTDengine client is installed successfully!${NC}"
     fi
+    touch ~/.taos_history
 
     rm -rf $(tar -tf taos.tar.gz)
 }
diff --git a/src/client/inc/tscLocalMerge.h b/src/client/inc/tscLocalMerge.h
index 397a60d140..4e579b0729 100644
--- a/src/client/inc/tscLocalMerge.h
+++ b/src/client/inc/tscLocalMerge.h
@@ -87,7 +87,6 @@ typedef struct SRetrieveSupport {
   SSqlObj *         pParentSql;
   tFilePage *       localBuffer;       // temp buffer, there is a buffer for each vnode to
   uint32_t          numOfRetry;        // record the number of retry times
-  pthread_mutex_t   queryMutex;
 } SRetrieveSupport;
 
 int32_t tscLocalReducerEnvCreate(SSqlObj *pSql, tExtMemBuffer ***pMemBuffer, tOrderDescriptor **pDesc,
diff --git a/src/client/inc/tscUtil.h b/src/client/inc/tscUtil.h
index cb285c8df1..f77897a74b 100644
--- a/src/client/inc/tscUtil.h
+++ b/src/client/inc/tscUtil.h
@@ -138,10 +138,10 @@ bool tscIsProjectionQuery(SQueryInfo* pQueryInfo);
 bool tscIsTwoStageSTableQuery(SQueryInfo* pQueryInfo, int32_t tableIndex);
 bool tscQueryTags(SQueryInfo* pQueryInfo);
 
-void tscAddSpecialColumnForSelect(SQueryInfo* pQueryInfo, int32_t outputColIndex, int16_t functionId, SColumnIndex* pIndex,
-                                  SSchema* pColSchema, int16_t colType);
+SSqlExpr* tscAddSpecialColumnForSelect(SQueryInfo* pQueryInfo, int32_t outputColIndex, int16_t functionId,
+                                       SColumnIndex* pIndex, SSchema* pColSchema, int16_t colType);
 
-int32_t tscSetTableFullName(STableMetaInfo* pTableMetaInfo, SSQLToken* pzTableName, SSqlObj* pSql);
+int32_t tscSetTableFullName(STableMetaInfo* pTableMetaInfo, SStrToken* pzTableName, SSqlObj* pSql);
 void    tscClearInterpInfo(SQueryInfo* pQueryInfo);
 
 bool tscIsInsertData(char* sqlstr);
@@ -194,11 +194,11 @@ SColumn* tscColumnListInsert(SArray* pColList, SColumnIndex* colIndex);
 SArray* tscColumnListClone(const SArray* src, int16_t tableIndex);
 void tscColumnListDestroy(SArray* pColList);
 
-int32_t tscValidateName(SSQLToken* pToken);
+int32_t tscValidateName(SStrToken* pToken);
 
 void tscIncStreamExecutionCount(void* pStream);
 
-bool tscValidateColumnId(STableMetaInfo* pTableMetaInfo, int32_t colId);
+bool tscValidateColumnId(STableMetaInfo* pTableMetaInfo, int32_t colId, int32_t numOfParams);
 
 // get starter position of metric query condition (query on tags) in SSqlCmd.payload
 SCond* tsGetSTableQueryCond(STagCond* pCond, uint64_t uid);
@@ -217,7 +217,7 @@ STableMetaInfo* tscGetTableMetaInfoFromCmd(SSqlCmd *pCmd, int32_t subClauseIndex
 STableMetaInfo* tscGetMetaInfo(SQueryInfo *pQueryInfo, int32_t tableIndex);
 
 SQueryInfo *tscGetQueryInfoDetail(SSqlCmd* pCmd, int32_t subClauseIndex);
-int32_t tscGetQueryInfoDetailSafely(SSqlCmd *pCmd, int32_t subClauseIndex, SQueryInfo** pQueryInfo);
+SQueryInfo *tscGetQueryInfoDetailSafely(SSqlCmd *pCmd, int32_t subClauseIndex);
 
 void tscClearTableMetaInfo(STableMetaInfo* pTableMetaInfo, bool removeFromCache);
 
diff --git a/src/client/inc/tsclient.h b/src/client/inc/tsclient.h
index e117f544bf..d2c52e972a 100644
--- a/src/client/inc/tsclient.h
+++ b/src/client/inc/tsclient.h
@@ -35,6 +35,40 @@ extern "C" {
 #include "qTsbuf.h"
 #include "tcmdtype.h"
 
+#if 0
+static UNUSED_FUNC void *u_malloc (size_t __size) {
+  uint32_t v = rand();
+
+  if (v % 5000 <= 0) {
+    return NULL;
+  } else {
+    return malloc(__size);
+  }
+}
+
+static UNUSED_FUNC void* u_calloc(size_t num, size_t __size) {
+  uint32_t v = rand();
+  if (v % 5000 <= 0) {
+    return NULL;
+  } else {
+    return calloc(num, __size);
+  }
+}
+
+static UNUSED_FUNC void* u_realloc(void* p, size_t __size) {
+  uint32_t v = rand();
+  if (v % 5000 <= 0) {
+    return NULL;
+  } else {
+    return realloc(p, __size);
+  }
+}
+
+#define calloc  u_calloc
+#define malloc  u_malloc
+#define realloc u_realloc
+#endif
+
 // forward declaration
 struct SSqlInfo;
 struct SLocalReducer;
@@ -195,9 +229,9 @@ typedef struct STableDataBlocks {
 
 typedef struct SQueryInfo {
   int16_t          command;       // the command may be different for each subclause, so keep it seperately.
-  uint32_t         type;          // query/insert/import type
+  uint32_t         type;          // query/insert type
   char             slidingTimeUnit;
-  STimeWindow      window;
+  STimeWindow      window;        // query time window
   int64_t          intervalTime;  // aggregation time interval
   int64_t          slidingTime;   // sliding window in mseconds
   SSqlGroupbyExpr  groupbyExpr;   // group by tags info
@@ -216,6 +250,7 @@ typedef struct SQueryInfo {
   char *           msg;           // pointer to the pCmd->payload to keep error message temporarily
   int64_t          clauseLimit;   // limit for current sub clause
   int64_t          prjOffset;     // offset value in the original sql expression, only applied at client side
+  int32_t          udColumnId;    // current user-defined constant output field column id, monotonically decreases from TSDB_UD_COLUMN_INDEX
 } SQueryInfo;
 
 typedef struct {
@@ -431,31 +466,36 @@ static FORCE_INLINE void tscGetResultColumnChr(SSqlRes* pRes, SFieldInfo* pField
   int32_t bytes = pInfo->pSqlExpr->resBytes;
 
   char* pData = pRes->data + pInfo->pSqlExpr->offset * pRes->numOfRows + bytes * pRes->row;
-  if (type == TSDB_DATA_TYPE_NCHAR || type == TSDB_DATA_TYPE_BINARY) {
-    int32_t realLen = varDataLen(pData);
-    assert(realLen <= bytes - VARSTR_HEADER_SIZE);
 
-    if (isNull(pData, type)) {
-      pRes->tsrow[columnIndex] = NULL;
+  // user defined constant value output columns
+  if (pInfo->pSqlExpr->colInfo.flag == TSDB_COL_UDC) {
+    if (type == TSDB_DATA_TYPE_NCHAR || type == TSDB_DATA_TYPE_BINARY) {
+      pData = pInfo->pSqlExpr->param[1].pz;
+      pRes->length[columnIndex] = pInfo->pSqlExpr->param[1].nLen;
+      pRes->tsrow[columnIndex] = (pInfo->pSqlExpr->param[1].nType == TSDB_DATA_TYPE_NULL) ? NULL : pData;
     } else {
-      pRes->tsrow[columnIndex] = ((tstr*)pData)->data;
-    }
+      assert(bytes == tDataTypeDesc[type].nSize);
 
-    if (realLen < pInfo->pSqlExpr->resBytes - VARSTR_HEADER_SIZE) { // todo refactor
-      *(pData + realLen + VARSTR_HEADER_SIZE) = 0;
+      pRes->tsrow[columnIndex] = isNull(pData, type) ? NULL : &pInfo->pSqlExpr->param[1].i64Key;
+      pRes->length[columnIndex] = bytes;
     }
-
-    pRes->length[columnIndex] = realLen;
   } else {
-    assert(bytes == tDataTypeDesc[type].nSize);
+    if (type == TSDB_DATA_TYPE_NCHAR || type == TSDB_DATA_TYPE_BINARY) {
+      int32_t realLen = varDataLen(pData);
+      assert(realLen <= bytes - VARSTR_HEADER_SIZE);
 
-    if (isNull(pData, type)) {
-      pRes->tsrow[columnIndex] = NULL;
+      pRes->tsrow[columnIndex] = (isNull(pData, type)) ? NULL : ((tstr *)pData)->data;
+      if (realLen < pInfo->pSqlExpr->resBytes - VARSTR_HEADER_SIZE) {  // todo refactor
+        *(pData + realLen + VARSTR_HEADER_SIZE) = 0;
+      }
+
+      pRes->length[columnIndex] = realLen;
     } else {
-      pRes->tsrow[columnIndex] = pData;
-    }
+      assert(bytes == tDataTypeDesc[type].nSize);
 
-    pRes->length[columnIndex] = bytes;
+      pRes->tsrow[columnIndex] = isNull(pData, type) ? NULL : pData;
+      pRes->length[columnIndex] = bytes;
+    }
   }
 }
 
diff --git a/src/client/jni/com_taosdata_jdbc_TSDBJNIConnector.h b/src/client/jni/com_taosdata_jdbc_TSDBJNIConnector.h
index d81bbd9b6d..eaea91d1bf 100644
--- a/src/client/jni/com_taosdata_jdbc_TSDBJNIConnector.h
+++ b/src/client/jni/com_taosdata_jdbc_TSDBJNIConnector.h
@@ -89,6 +89,14 @@ JNIEXPORT jstring JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getErrMsgImp
 JNIEXPORT jlong JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getResultSetImp
   (JNIEnv *env, jobject jobj, jlong con, jlong tres);
 
+/*
+ * Class:     com_taosdata_jdbc_TSDBJNIConnector
+ * Method:    isUpdateQueryImp
+ * Signature: (J)J
+ */
+JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_isUpdateQueryImp
+  (JNIEnv *env, jobject jobj, jlong con, jlong tres);
+
 /*
  * Class:     com_taosdata_jdbc_TSDBJNIConnector
  * Method:    freeResultSetImp
diff --git a/src/client/src/taos.rc.in b/src/client/src/taos.rc.in
index 05dbd9bb7d..751be85fd0 100644
--- a/src/client/src/taos.rc.in
+++ b/src/client/src/taos.rc.in
@@ -1,6 +1,6 @@
 1 VERSIONINFO
- FILEVERSION ${TD_VER_1}, ${TD_VER_2}, ${TD_VER_3}
- PRODUCTVERSION ${TD_VER_1}, ${TD_VER_2}, ${TD_VER_3}
+ FILEVERSION ${TD_VER_NUMBER}
+ PRODUCTVERSION ${TD_VER_NUMBER}
  FILEFLAGSMASK 0x17L
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -16,12 +16,12 @@ BEGIN
         BLOCK "040904b0"
         BEGIN
             VALUE "FileDescription", "Native C Driver for TDengine"
-            VALUE "FileVersion", "${TD_VER_1}, ${TD_VER_2}, ${TD_VER_3}"
+            VALUE "FileVersion", "${TD_VER_NUMBER}"
             VALUE "InternalName", "taos.dll(${TD_VER_CPUTYPE})"
             VALUE "LegalCopyright", "Copyright (C) 2020 TAOS Data"
             VALUE "OriginalFilename", ""
             VALUE "ProductName", "taos.dll(${TD_VER_CPUTYPE})"
-            VALUE "ProductVersion", "${TD_VER_1}.${TD_VER_2}.${TD_VER_3}.${TD_VER_4}"
+            VALUE "ProductVersion", "${TD_VER_NUMBER}"
         END
     END
     BLOCK "VarFileInfo"
diff --git a/src/client/src/tscAsync.c b/src/client/src/tscAsync.c
index b05aef76eb..4643d255dc 100644
--- a/src/client/src/tscAsync.c
+++ b/src/client/src/tscAsync.c
@@ -433,7 +433,8 @@ void tscTableMetaCallBack(void *param, TAOS_RES *res, int code) {
     tscError("%p get tableMeta failed, code:%s", pSql, tstrerror(code));
     goto _error;
   } else {
-    tscDebug("%p get tableMeta successfully", pSql);
+    const char* msg = (pCmd->command == TSDB_SQL_STABLEVGROUP)? "vgroup-list":"table-meta";
+    tscDebug("%p get %s successfully", pSql, msg);
   }
 
   if (pSql->pStream == NULL) {
diff --git a/src/client/src/tscFunctionImpl.c b/src/client/src/tscFunctionImpl.c
index 04c6ef47a5..e74fcba246 100644
--- a/src/client/src/tscFunctionImpl.c
+++ b/src/client/src/tscFunctionImpl.c
@@ -1813,23 +1813,19 @@ static void last_dist_func_second_merge(SQLFunctionCtx *pCtx) {
  * NOTE: last_row does not use the interResultBuf to keep the result
  */
 static void last_row_function(SQLFunctionCtx *pCtx) {
-  assert(pCtx->size == 1);
-  
+  assert(pCtx->size >= 1);
   char *pData = GET_INPUT_CHAR(pCtx);
-  assignVal(pCtx->aOutputBuf, pData, pCtx->inputBytes, pCtx->inputType);
+
+  // assign the last element in current data block
+  assignVal(pCtx->aOutputBuf, pData + (pCtx->size - 1) * pCtx->inputBytes, pCtx->inputBytes, pCtx->inputType);
   
   SResultInfo *pResInfo = GET_RES_INFO(pCtx);
   pResInfo->hasResult = DATA_SET_FLAG;
   
-  SLastrowInfo *pInfo = (SLastrowInfo *)pResInfo->interResultBuf;
-  pInfo->ts = pCtx->ptsList[0];
-  
-  pInfo->hasResult = DATA_SET_FLAG;
-  
-  // set the result to final result buffer
+  // set the result to final result buffer in case of super table query
   if (pResInfo->superTableQ) {
     SLastrowInfo *pInfo1 = (SLastrowInfo *)(pCtx->aOutputBuf + pCtx->inputBytes);
-    pInfo1->ts = pCtx->ptsList[0];
+    pInfo1->ts = pCtx->ptsList[pCtx->size - 1];
     pInfo1->hasResult = DATA_SET_FLAG;
     
     DO_UPDATE_TAG_COLUMNS(pCtx, pInfo1->ts);
@@ -2038,7 +2034,7 @@ static void copyTopBotRes(SQLFunctionCtx *pCtx, int32_t type) {
   tValuePair **tvp = pRes->res;
   
   int32_t step = QUERY_ASC_FORWARD_STEP;
-  int32_t len = GET_RES_INFO(pCtx)->numOfRes;
+  int32_t len = (int32_t)(GET_RES_INFO(pCtx)->numOfRes);
   
   switch (type) {
     case TSDB_DATA_TYPE_INT: {
@@ -2412,10 +2408,10 @@ static void top_bottom_func_finalizer(SQLFunctionCtx *pCtx) {
   // user specify the order of output by sort the result according to timestamp
   if (pCtx->param[1].i64Key == PRIMARYKEY_TIMESTAMP_COL_INDEX) {
     __compar_fn_t comparator = (pCtx->param[2].i64Key == TSDB_ORDER_ASC) ? resAscComparFn : resDescComparFn;
-    qsort(tvp, pResInfo->numOfRes, POINTER_BYTES, comparator);
+    qsort(tvp, (size_t)pResInfo->numOfRes, POINTER_BYTES, comparator);
   } else if (pCtx->param[1].i64Key > PRIMARYKEY_TIMESTAMP_COL_INDEX) {
     __compar_fn_t comparator = (pCtx->param[2].i64Key == TSDB_ORDER_ASC) ? resDataAscComparFn : resDataDescComparFn;
-    qsort(tvp, pResInfo->numOfRes, POINTER_BYTES, comparator);
+    qsort(tvp, (size_t)pResInfo->numOfRes, POINTER_BYTES, comparator);
   }
   
   GET_TRUE_DATA_TYPE();
@@ -2909,33 +2905,41 @@ static FORCE_INLINE void date_col_output_function_f(SQLFunctionCtx *pCtx, int32_
 }
 
 static void col_project_function(SQLFunctionCtx *pCtx) {
+  // the number of output rows should not affect the final number of rows, so set it to be 0
+  if (pCtx->numOfParams == 2) {
+    return;
+  }
+
   INC_INIT_VAL(pCtx, pCtx->size);
-  
+
   char *pData = GET_INPUT_CHAR(pCtx);
   if (pCtx->order == TSDB_ORDER_ASC) {
-    memcpy(pCtx->aOutputBuf, pData, (size_t)pCtx->size * pCtx->inputBytes);
+    memcpy(pCtx->aOutputBuf, pData, (size_t) pCtx->size * pCtx->inputBytes);
   } else {
     for(int32_t i = 0; i < pCtx->size; ++i) {
       memcpy(pCtx->aOutputBuf + (pCtx->size - 1 - i) * pCtx->inputBytes, pData + i * pCtx->inputBytes,
              pCtx->inputBytes);
     }
   }
-  
+
   pCtx->aOutputBuf += pCtx->size * pCtx->outputBytes;
 }
 
 static void col_project_function_f(SQLFunctionCtx *pCtx, int32_t index) {
   SResultInfo *pResInfo = GET_RES_INFO(pCtx);
-  
+  if (pCtx->numOfParams == 2) {  // the number of output rows should not affect the final number of rows, so set it to be 0
+    return;
+  }
+
   // only one output
   if (pCtx->param[0].i64Key == 1 && pResInfo->numOfRes >= 1) {
     return;
   }
-  
+
   INC_INIT_VAL(pCtx, 1);
   char *pData = GET_INPUT_CHAR_INDEX(pCtx, index);
   memcpy(pCtx->aOutputBuf, pData, pCtx->inputBytes);
-  
+
   pCtx->aOutputBuf += pCtx->inputBytes;
 }
 
@@ -3903,11 +3907,11 @@ static void ts_comp_function(SQLFunctionCtx *pCtx) {
   
   // primary ts must be existed, so no need to check its existance
   if (pCtx->order == TSDB_ORDER_ASC) {
-    tsBufAppend(pTSbuf, 0, pCtx->tag.i64Key, input, pCtx->size * TSDB_KEYSIZE);
+    tsBufAppend(pTSbuf, 0, &pCtx->tag, input, pCtx->size * TSDB_KEYSIZE);
   } else {
     for (int32_t i = pCtx->size - 1; i >= 0; --i) {
       char *d = GET_INPUT_CHAR_INDEX(pCtx, i);
-      tsBufAppend(pTSbuf, 0, pCtx->tag.i64Key, d, TSDB_KEYSIZE);
+      tsBufAppend(pTSbuf, 0, &pCtx->tag, d, TSDB_KEYSIZE);
     }
   }
   
@@ -3926,7 +3930,7 @@ static void ts_comp_function_f(SQLFunctionCtx *pCtx, int32_t index) {
   
   STSBuf *pTSbuf = pInfo->pTSBuf;
   
-  tsBufAppend(pTSbuf, 0, pCtx->tag.i64Key, pData, TSDB_KEYSIZE);
+  tsBufAppend(pTSbuf, 0, &pCtx->tag, pData, TSDB_KEYSIZE);
   SET_VAL(pCtx, pCtx->size, 1);
   
   pResInfo->hasResult = DATA_SET_FLAG;
diff --git a/src/client/src/tscLocalMerge.c b/src/client/src/tscLocalMerge.c
index 9dc2210ab6..563c9fa84e 100644
--- a/src/client/src/tscLocalMerge.c
+++ b/src/client/src/tscLocalMerge.c
@@ -370,7 +370,7 @@ void tscCreateLocalReducer(tExtMemBuffer **pMemBuffer, int32_t numOfBuffer, tOrd
   STableMetaInfo *pTableMetaInfo = tscGetTableMetaInfoFromCmd(pCmd, pCmd->clauseIndex, 0);
   STableComInfo tinfo = tscGetTableInfo(pTableMetaInfo->pTableMeta);
   
-  TSKEY stime = MIN(pQueryInfo->window.skey, pQueryInfo->window.ekey);
+  TSKEY stime = (pQueryInfo->order.order == TSDB_ORDER_ASC)? pQueryInfo->window.skey : pQueryInfo->window.ekey;
   int64_t revisedSTime =
       taosGetIntervalStartTimestamp(stime, pQueryInfo->slidingTime, pQueryInfo->intervalTime, pQueryInfo->slidingTimeUnit, tinfo.precision);
   
@@ -843,28 +843,6 @@ void savePrevRecordAndSetupFillInfo(SLocalReducer *pLocalReducer, SQueryInfo *pQ
   tColModelAppend(pModel, pLocalReducer->discardData, pLocalReducer->prevRowOfInput, 0, 1, 1);
 }
 
-static void reversedCopyFromInterpolationToDstBuf(SQueryInfo *pQueryInfo, SSqlRes *pRes, tFilePage **pResPages,
-                                                  SLocalReducer *pLocalReducer) {
-  assert(0);
-  size_t size = tscSqlExprNumOfExprs(pQueryInfo);
-  
-  for (int32_t i = 0; i < size; ++i) {
-    TAOS_FIELD *pField = tscFieldInfoGetField(&pQueryInfo->fieldsInfo, i);
-
-    int32_t offset = tscFieldInfoGetOffset(pQueryInfo, i);
-    assert(offset == getColumnModelOffset(pLocalReducer->resColModel, i));
-
-    char *src = pResPages[i]->data + (pRes->numOfRows - 1) * pField->bytes;
-    char *dst = pRes->data + pRes->numOfRows * offset;
-
-    for (int32_t j = 0; j < pRes->numOfRows; ++j) {
-      memcpy(dst, src, (size_t)pField->bytes);
-      dst += pField->bytes;
-      src -= pField->bytes;
-    }
-  }
-}
-
 static void genFinalResWithoutFill(SSqlRes* pRes, SLocalReducer *pLocalReducer, SQueryInfo* pQueryInfo) {
   assert(pQueryInfo->intervalTime == 0 || pQueryInfo->fillType == TSDB_FILL_NONE);
 
@@ -925,7 +903,8 @@ static void doFillResult(SSqlObj *pSql, SLocalReducer *pLocalReducer, bool doneO
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
   SFillInfo  *pFillInfo = pLocalReducer->pFillInfo;
 
-  int64_t actualETime = MAX(pQueryInfo->window.skey, pQueryInfo->window.ekey);
+  // todo extract function
+  int64_t actualETime = (pQueryInfo->order.order == TSDB_ORDER_ASC)? pQueryInfo->window.ekey: pQueryInfo->window.skey;
 
   tFilePage **pResPages = malloc(POINTER_BYTES * pQueryInfo->fieldsInfo.numOfOutput);
   for (int32_t i = 0; i < pQueryInfo->fieldsInfo.numOfOutput; ++i) {
@@ -984,14 +963,10 @@ static void doFillResult(SSqlObj *pSql, SLocalReducer *pLocalReducer, bool doneO
       savePrevRecordAndSetupFillInfo(pLocalReducer, pQueryInfo, pFillInfo);
     }
 
-    if (pQueryInfo->order.order == TSDB_ORDER_ASC) {
-      for (int32_t i = 0; i < pQueryInfo->fieldsInfo.numOfOutput; ++i) {
-        TAOS_FIELD *pField = tscFieldInfoGetField(&pQueryInfo->fieldsInfo, i);
-        int16_t     offset = getColumnModelOffset(pLocalReducer->resColModel, i);
-        memcpy(pRes->data + offset * pRes->numOfRows, pResPages[i]->data, (size_t)(pField->bytes * pRes->numOfRows));
-      }
-    } else {  // todo bug??
-      reversedCopyFromInterpolationToDstBuf(pQueryInfo, pRes, pResPages, pLocalReducer);
+    for (int32_t i = 0; i < pQueryInfo->fieldsInfo.numOfOutput; ++i) {
+      TAOS_FIELD *pField = tscFieldInfoGetField(&pQueryInfo->fieldsInfo, i);
+      int16_t     offset = getColumnModelOffset(pLocalReducer->resColModel, i);
+      memcpy(pRes->data + offset * pRes->numOfRows, pResPages[i]->data, (size_t)(pField->bytes * pRes->numOfRows));
     }
 
     pRes->numOfRowsGroup += pRes->numOfRows;
@@ -1248,8 +1223,6 @@ bool genFinalResults(SSqlObj *pSql, SLocalReducer *pLocalReducer, bool noMoreCur
   printf("final result before interpo:\n");
 //  tColModelDisplay(pLocalReducer->resColModel, pLocalReducer->pBufForInterpo, pResBuf->num, pResBuf->num);
 #endif
-  
-  
 
   // no interval query, no fill operation
   if (pQueryInfo->intervalTime == 0 || pQueryInfo->fillType == TSDB_FILL_NONE) {
@@ -1257,7 +1230,9 @@ bool genFinalResults(SSqlObj *pSql, SLocalReducer *pLocalReducer, bool noMoreCur
   } else {
     SFillInfo* pFillInfo = pLocalReducer->pFillInfo;
     if (pFillInfo != NULL) {
-      taosFillSetStartInfo(pFillInfo, (int32_t)pResBuf->num, pQueryInfo->window.ekey);
+      TSKEY ekey = (pQueryInfo->order.order == TSDB_ORDER_ASC)? pQueryInfo->window.ekey: pQueryInfo->window.skey;
+
+      taosFillSetStartInfo(pFillInfo, (int32_t)pResBuf->num, ekey);
       taosFillCopyInputDataFromOneFilePage(pFillInfo, pResBuf);
     }
     
@@ -1292,7 +1267,7 @@ static void resetEnvForNewResultset(SSqlRes *pRes, SSqlCmd *pCmd, SLocalReducer
 
   // for group result interpolation, do not return if not data is generated
   if (pQueryInfo->fillType != TSDB_FILL_NONE) {
-    TSKEY skey = MIN(pQueryInfo->window.skey, pQueryInfo->window.ekey);
+    TSKEY skey = (pQueryInfo->order.order == TSDB_ORDER_ASC)? pQueryInfo->window.skey:pQueryInfo->window.ekey;//MIN(pQueryInfo->window.skey, pQueryInfo->window.ekey);
     int64_t newTime =
         taosGetIntervalStartTimestamp(skey, pQueryInfo->slidingTime, pQueryInfo->intervalTime, pQueryInfo->slidingTimeUnit, precision);
     taosResetFillInfo(pLocalReducer->pFillInfo, newTime);
@@ -1345,7 +1320,7 @@ static bool doHandleLastRemainData(SSqlObj *pSql) {
     // if fillType == TSDB_FILL_NONE, return directly
     if (pQueryInfo->fillType != TSDB_FILL_NONE &&
       ((pRes->numOfRowsGroup < pQueryInfo->limit.limit && pQueryInfo->limit.limit > 0) || (pQueryInfo->limit.limit < 0))) {
-      int64_t etime = (pQueryInfo->window.skey < pQueryInfo->window.ekey) ? pQueryInfo->window.ekey : pQueryInfo->window.skey;
+      int64_t etime = (pQueryInfo->order.order == TSDB_ORDER_ASC)? pQueryInfo->window.ekey : pQueryInfo->window.skey;
 
       int32_t rows = (int32_t)getFilledNumOfRes(pFillInfo, etime, pLocalReducer->resColModel->capacity);
       if (rows > 0) {
@@ -1402,13 +1377,12 @@ int32_t tscDoLocalMerge(SSqlObj *pSql) {
   tscResetForNextRetrieve(pRes);
 
   if (pSql->signature != pSql || pRes == NULL || pRes->pLocalReducer == NULL) {  // all data has been processed
-    tscDebug("%p %s call the drop local reducer", pSql, __FUNCTION__);
-    tscDestroyLocalReducer(pSql);
-    return 0;
+    tscError("%p local merge abort due to error occurs, code:%s", pSql, tstrerror(pRes->code));
+    return pRes->code;
   }
 
   SLocalReducer *pLocalReducer = pRes->pLocalReducer;
-  SQueryInfo *   pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
+  SQueryInfo    *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
 
   // set the data merge in progress
   int32_t prevStatus =
@@ -1503,8 +1477,8 @@ int32_t tscDoLocalMerge(SSqlObj *pSql) {
          * so the processing of previous group is completed.
          */
         int32_t numOfRes = finalizeRes(pQueryInfo, pLocalReducer);
+        bool   sameGroup = isSameGroup(pCmd, pLocalReducer, pLocalReducer->prevRowOfInput, tmpBuffer);
 
-        bool       sameGroup = isSameGroup(pCmd, pLocalReducer, pLocalReducer->prevRowOfInput, tmpBuffer);
         tFilePage *pResBuf = pLocalReducer->pResultBuf;
 
         /*
diff --git a/src/client/src/tscParseInsert.c b/src/client/src/tscParseInsert.c
index cb49bd80b7..47bfe0fcdc 100644
--- a/src/client/src/tscParseInsert.c
+++ b/src/client/src/tscParseInsert.c
@@ -40,7 +40,7 @@ enum {
 
 static int32_t tscAllocateMemIfNeed(STableDataBlocks *pDataBlock, int32_t rowSize, int32_t * numOfRows);
 
-static int32_t tscToInteger(SSQLToken *pToken, int64_t *value, char **endPtr) {
+static int32_t tscToInteger(SStrToken *pToken, int64_t *value, char **endPtr) {
   if (pToken->n == 0) {
     return TK_ILLEGAL;
   }
@@ -73,7 +73,7 @@ static int32_t tscToInteger(SSQLToken *pToken, int64_t *value, char **endPtr) {
   return pToken->type;
 }
 
-static int32_t tscToDouble(SSQLToken *pToken, double *value, char **endPtr) {
+static int32_t tscToDouble(SStrToken *pToken, double *value, char **endPtr) {
   if (pToken->n == 0) {
     return TK_ILLEGAL;
   }
@@ -89,9 +89,9 @@ static int32_t tscToDouble(SSQLToken *pToken, double *value, char **endPtr) {
   return pToken->type;
 }
 
-int tsParseTime(SSQLToken *pToken, int64_t *time, char **next, char *error, int16_t timePrec) {
+int tsParseTime(SStrToken *pToken, int64_t *time, char **next, char *error, int16_t timePrec) {
   int32_t   index = 0;
-  SSQLToken sToken;
+  SStrToken sToken;
   int64_t   interval;
   int64_t   useconds = 0;
   char *    pTokenEnd = *next;
@@ -128,7 +128,7 @@ int tsParseTime(SSQLToken *pToken, int64_t *time, char **next, char *error, int1
    * time expression:
    * e.g., now+12a, now-5h
    */
-  SSQLToken valueToken;
+  SStrToken valueToken;
   index = 0;
   sToken = tStrGetToken(pTokenEnd, &index, false, 0, NULL);
   pTokenEnd += index;
@@ -163,7 +163,7 @@ int tsParseTime(SSQLToken *pToken, int64_t *time, char **next, char *error, int1
   return TSDB_CODE_SUCCESS;
 }
 
-int32_t tsParseOneColumnData(SSchema *pSchema, SSQLToken *pToken, char *payload, char *msg, char **str, bool primaryKey,
+int32_t tsParseOneColumnData(SSchema *pSchema, SStrToken *pToken, char *payload, char *msg, char **str, bool primaryKey,
                              int16_t timePrec) {
   int64_t iv;
   int32_t numType;
@@ -409,7 +409,7 @@ static int32_t tsCheckTimestamp(STableDataBlocks *pDataBlocks, const char *start
 int tsParseOneRowData(char **str, STableDataBlocks *pDataBlocks, SSchema schema[], SParsedDataColInfo *spd, char *error,
                       int16_t timePrec, int32_t *code, char *tmpTokenBuf) {
   int32_t index = 0;
-  SSQLToken sToken = {0};
+  SStrToken sToken = {0};
   char *    payload = pDataBlocks->pData + pDataBlocks->size;
 
   // 1. set the parsed value from sql string
@@ -524,7 +524,7 @@ static int32_t rowDataCompar(const void *lhs, const void *rhs) {
 int tsParseValues(char **str, STableDataBlocks *pDataBlock, STableMeta *pTableMeta, int maxRows,
                   SParsedDataColInfo *spd, char *error, int32_t *code, char *tmpTokenBuf) {
   int32_t   index = 0;
-  SSQLToken sToken;
+  SStrToken sToken;
 
   int16_t numOfRows = 0;
 
@@ -734,8 +734,8 @@ static int32_t doParseInsertStatement(SSqlObj *pSql, void *pTableList, char **st
 
 static int32_t tscCheckIfCreateTable(char **sqlstr, SSqlObj *pSql) {
   int32_t   index = 0;
-  SSQLToken sToken = {0};
-  SSQLToken tableToken = {0};
+  SStrToken sToken = {0};
+  SStrToken tableToken = {0};
   int32_t   code = TSDB_CODE_SUCCESS;
   
   const int32_t TABLE_INDEX = 0;
@@ -993,7 +993,7 @@ static int32_t tscCheckIfCreateTable(char **sqlstr, SSqlObj *pSql) {
   return code;
 }
 
-int validateTableName(char *tblName, int len, SSQLToken* psTblToken) {
+int validateTableName(char *tblName, int len, SStrToken* psTblToken) {
   tstrncpy(psTblToken->z, tblName, TSDB_TABLE_FNAME_LEN);
 
   psTblToken->n    = len;
@@ -1031,11 +1031,11 @@ int tsParseInsertSql(SSqlObj *pSql) {
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, 0);
   assert(pQueryInfo != NULL);
 
-  STableMetaInfo *pTableMetaInfo = NULL;
-  if (pQueryInfo->numOfTables == 0) {
-    pTableMetaInfo = tscAddEmptyMetaInfo(pQueryInfo);
-  } else {
-    pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
+  STableMetaInfo *pTableMetaInfo = (pQueryInfo->numOfTables == 0)? tscAddEmptyMetaInfo(pQueryInfo):tscGetMetaInfo(pQueryInfo, 0);
+  if (pTableMetaInfo == NULL) {
+    terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
+    code = terrno;
+    return code;
   }
 
   if ((code = tscAllocPayload(pCmd, TSDB_DEFAULT_PAYLOAD_SIZE)) != TSDB_CODE_SUCCESS) {
@@ -1057,7 +1057,7 @@ int tsParseInsertSql(SSqlObj *pSql) {
 
   while (1) {
     int32_t   index = 0;
-    SSQLToken sToken = tStrGetToken(str, &index, false, 0, NULL);
+    SStrToken sToken = tStrGetToken(str, &index, false, 0, NULL);
 
     // no data in the sql string anymore.
     if (sToken.n == 0) {
@@ -1083,7 +1083,7 @@ int tsParseInsertSql(SSqlObj *pSql) {
 
     pCmd->curSql = sToken.z;
     char buf[TSDB_TABLE_FNAME_LEN];
-    SSQLToken sTblToken;
+    SStrToken sTblToken;
     sTblToken.z = buf;
     // Check if the table name available or not
     if (validateTableName(sToken.z, sToken.n, &sTblToken) != TSDB_CODE_SUCCESS) {
@@ -1285,15 +1285,14 @@ int tsInsertInitialCheck(SSqlObj *pSql) {
   int32_t  index = 0;
   SSqlCmd *pCmd = &pSql->cmd;
 
-  SSQLToken sToken = tStrGetToken(pSql->sqlstr, &index, false, 0, NULL);
+  SStrToken sToken = tStrGetToken(pSql->sqlstr, &index, false, 0, NULL);
   assert(sToken.type == TK_INSERT || sToken.type == TK_IMPORT);
 
   pCmd->count = 0;
   pCmd->command = TSDB_SQL_INSERT;
   pSql->res.numOfRows = 0;
 
-  SQueryInfo *pQueryInfo = NULL;
-  tscGetQueryInfoDetailSafely(pCmd, pCmd->clauseIndex, &pQueryInfo);
+  SQueryInfo *pQueryInfo = tscGetQueryInfoDetailSafely(pCmd, pCmd->clauseIndex);
 
   TSDB_QUERY_SET_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_INSERT | pCmd->insertType);
 
diff --git a/src/client/src/tscPrepare.c b/src/client/src/tscPrepare.c
index b996dd958a..620e8ea57a 100644
--- a/src/client/src/tscPrepare.c
+++ b/src/client/src/tscPrepare.c
@@ -155,7 +155,7 @@ static int normalStmtPrepare(STscStmt* stmt) {
   uint32_t i = 0, start = 0;
 
   while (sql[i] != 0) {
-    SSQLToken token = {0};
+    SStrToken token = {0};
     token.n = tSQLGetToken(sql + i, &token.type);
 
     if (token.type == TK_QUESTION) {
diff --git a/src/client/src/tscProfile.c b/src/client/src/tscProfile.c
index f48e7b7691..6ff97e9d00 100644
--- a/src/client/src/tscProfile.c
+++ b/src/client/src/tscProfile.c
@@ -285,9 +285,9 @@ void tscKillConnection(STscObj *pObj) {
 
   SSqlObj *pSql = pObj->sqlList;
   while (pSql) {
-    //taosStopRpcConn(pSql->thandle);
     pSql = pSql->next;
   }
+  
 
   SSqlStream *pStream = pObj->streamList;
   while (pStream) {
diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index d108349085..5ce4c7125f 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -33,8 +33,8 @@
 
 #define DEFAULT_PRIMARY_TIMESTAMP_COL_NAME "_c0"
 
-// -1 is tbname column index, so here use the -2 as the initial value
-#define COLUMN_INDEX_INITIAL_VAL (-2)
+// -1 is tbname column index, so here use the -3 as the initial value
+#define COLUMN_INDEX_INITIAL_VAL (-3)
 #define COLUMN_INDEX_INITIALIZER \
   { COLUMN_INDEX_INITIAL_VAL, COLUMN_INDEX_INITIAL_VAL }
 #define COLUMN_INDEX_VALIDE(index) (((index).tableIndex >= 0) && ((index).columnIndex >= TSDB_TBNAME_COLUMN_INDEX))
@@ -51,12 +51,12 @@ static int32_t setShowInfo(SSqlObj* pSql, SSqlInfo* pInfo);
 static char*   getAccountId(SSqlObj* pSql);
 
 static bool has(tFieldList* pFieldList, int32_t startIdx, const char* name);
-static void getCurrentDBName(SSqlObj* pSql, SSQLToken* pDBToken);
-static bool hasSpecifyDB(SSQLToken* pTableName);
+static void getCurrentDBName(SSqlObj* pSql, SStrToken* pDBToken);
+static bool hasSpecifyDB(SStrToken* pTableName);
 static bool validateTableColumnInfo(tFieldList* pFieldList, SSqlCmd* pCmd);
 static bool validateTagParams(tFieldList* pTagsList, tFieldList* pFieldList, SSqlCmd* pCmd);
 
-static int32_t setObjFullName(char* fullName, const char* account, SSQLToken* pDB, SSQLToken* tableName, int32_t* len);
+static int32_t setObjFullName(char* fullName, const char* account, SStrToken* pDB, SStrToken* tableName, int32_t* len);
 
 static void getColumnName(tSQLExprItem* pItem, char* resultFieldName, int32_t nameLength);
 static void getRevisedName(char* resultFieldName, int32_t functionId, int32_t maxLen, char* columnName);
@@ -65,11 +65,11 @@ static int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int3
 static int32_t insertResultField(SQueryInfo* pQueryInfo, int32_t outputIndex, SColumnList* pIdList, int16_t bytes,
                                  int8_t type, char* fieldName, SSqlExpr* pSqlExpr);
 static int32_t changeFunctionID(int32_t optr, int16_t* functionId);
-static int32_t parseSelectClause(SSqlCmd* pCmd, int32_t clauseIndex, tSQLExprList* pSelection, bool isSTable);
+static int32_t parseSelectClause(SSqlCmd* pCmd, int32_t clauseIndex, tSQLExprList* pSelection, bool isSTable, bool joinQuery);
 
 static bool validateIpAddress(const char* ip, size_t size);
 static bool hasUnsupportFunctionsForSTableQuery(SSqlCmd* pCmd, SQueryInfo* pQueryInfo);
-static bool functionCompatibleCheck(SQueryInfo* pQueryInfo);
+static bool functionCompatibleCheck(SQueryInfo* pQueryInfo, bool joinQuery);
 static void setColumnOffsetValueInResultset(SQueryInfo* pQueryInfo);
 
 static int32_t parseGroupbyClause(SQueryInfo* pQueryInfo, tVariantList* pList, SSqlCmd* pCmd);
@@ -100,11 +100,11 @@ static bool hasTimestampForPointInterpQuery(SQueryInfo* pQueryInfo);
 
 static int32_t parseLimitClause(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t index, SQuerySQL* pQuerySql, SSqlObj* pSql);
 static int32_t parseCreateDBOptions(SSqlCmd* pCmd, SCreateDBInfo* pCreateDbSql);
-static int32_t getColumnIndexByName(SSqlCmd* pCmd, const SSQLToken* pToken, SQueryInfo* pQueryInfo, SColumnIndex* pIndex);
-static int32_t getTableIndexByName(SSQLToken* pToken, SQueryInfo* pQueryInfo, SColumnIndex* pIndex);
+static int32_t getColumnIndexByName(SSqlCmd* pCmd, const SStrToken* pToken, SQueryInfo* pQueryInfo, SColumnIndex* pIndex);
+static int32_t getTableIndexByName(SStrToken* pToken, SQueryInfo* pQueryInfo, SColumnIndex* pIndex);
 static int32_t optrToString(tSQLExpr* pExpr, char** exprString);
 
-static int32_t getTableIndexImpl(SSQLToken* pTableToken, SQueryInfo* pQueryInfo, SColumnIndex* pIndex);
+static int32_t getTableIndexImpl(SStrToken* pTableToken, SQueryInfo* pQueryInfo, SColumnIndex* pIndex);
 static int32_t doFunctionsCompatibleCheck(SSqlCmd* pCmd, SQueryInfo* pQueryInfo);
 static int32_t doLocalQueryProcess(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SQuerySQL* pQuerySql);
 static int32_t tscCheckCreateDbParams(SSqlCmd* pCmd, SCMCreateDbMsg* pCreate);
@@ -151,7 +151,7 @@ static int setColumnFilterInfoForTimestamp(SSqlCmd* pCmd, SQueryInfo* pQueryInfo
   return TSDB_CODE_SUCCESS;
 }
 
-static int32_t handlePassword(SSqlCmd* pCmd, SSQLToken* pPwd) {
+static int32_t handlePassword(SSqlCmd* pCmd, SStrToken* pPwd) {
   const char* msg1 = "password can not be empty";
   const char* msg2 = "name or password too long";
   const char* msg3 = "password needs single quote marks enclosed";
@@ -179,20 +179,24 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
     return TSDB_CODE_TSC_APP_ERROR;
   }
 
-  SSqlCmd*    pCmd = &(pSql->cmd);
-  SQueryInfo* pQueryInfo = NULL;
+  SSqlCmd* pCmd = &pSql->cmd;
+  SSqlRes* pRes = &pSql->res;
 
+  int32_t code = TSDB_CODE_SUCCESS;
   if (!pInfo->valid) {
     return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), pInfo->pzErrMsg);
   }
 
-  int32_t code = tscGetQueryInfoDetailSafely(pCmd, pCmd->clauseIndex, &pQueryInfo);
+  SQueryInfo* pQueryInfo = tscGetQueryInfoDetailSafely(pCmd, pCmd->clauseIndex);
+  if (pQueryInfo == NULL) {
+    pRes->code = terrno;
+    return pRes->code;
+  }
 
-  STableMetaInfo* pTableMetaInfo = NULL;
-  if (pQueryInfo->numOfTables == 0) {
-    pTableMetaInfo = tscAddEmptyMetaInfo(pQueryInfo);
-  } else {
-    pTableMetaInfo = pQueryInfo->pTableMetaInfo[0];
+  STableMetaInfo* pTableMetaInfo = (pQueryInfo->numOfTables == 0)? tscAddEmptyMetaInfo(pQueryInfo) : pQueryInfo->pTableMetaInfo[0];
+  if (pTableMetaInfo == NULL) {
+    pRes->code = TSDB_CODE_TSC_OUT_OF_MEMORY;
+    return pRes->code;
   }
 
   pCmd->command = pInfo->type;
@@ -206,7 +210,7 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
       const char* msg2 = "invalid name";
       const char* msg3 = "param name too long";
 
-      SSQLToken* pzName = &pInfo->pDCLInfo->a[0];
+      SStrToken* pzName = &pInfo->pDCLInfo->a[0];
       if ((pInfo->type != TSDB_SQL_DROP_DNODE) && (tscValidateName(pzName) != TSDB_CODE_SUCCESS)) {
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg2);
       }
@@ -241,7 +245,7 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
 
     case TSDB_SQL_USE_DB: {
       const char* msg = "invalid db name";
-      SSQLToken*  pToken = &pInfo->pDCLInfo->a[0];
+      SStrToken*  pToken = &pInfo->pDCLInfo->a[0];
 
       if (tscValidateName(pToken) != TSDB_CODE_SUCCESS) {
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg);
@@ -296,7 +300,7 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg);
       }
 
-      SSQLToken* pIpAddr = &pInfo->pDCLInfo->a[0];
+      SStrToken* pIpAddr = &pInfo->pDCLInfo->a[0];
       pIpAddr->n = strdequote(pIpAddr->z);
       break;
     }
@@ -307,8 +311,8 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
       const char* msg2 = "invalid user/account name";
       const char* msg3 = "name too long";
 
-      SSQLToken* pName = &pInfo->pDCLInfo->user.user;
-      SSQLToken* pPwd = &pInfo->pDCLInfo->user.passwd;
+      SStrToken* pName = &pInfo->pDCLInfo->user.user;
+      SStrToken* pPwd = &pInfo->pDCLInfo->user.passwd;
 
       if (handlePassword(pCmd, pPwd) != TSDB_CODE_SUCCESS) {
         return TSDB_CODE_TSC_INVALID_SQL;
@@ -337,7 +341,7 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
     }
 
     case TSDB_SQL_DESCRIBE_TABLE: {
-      SSQLToken*  pToken = &pInfo->pDCLInfo->a[0];
+      SStrToken*  pToken = &pInfo->pDCLInfo->a[0];
       const char* msg2 = "table name is too long";
       const char* msg1 = "invalid table name";
 
@@ -400,8 +404,8 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
       // tDCLSQL* pDCL = pInfo->pDCLInfo;
 
       SUserInfo* pUser = &pInfo->pDCLInfo->user;
-      SSQLToken* pName = &pUser->user;
-      SSQLToken* pPwd = &pUser->passwd;
+      SStrToken* pName = &pUser->user;
+      SStrToken* pPwd = &pUser->passwd;
 
       if (pName->n >= TSDB_USER_LEN) {
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg3);
@@ -423,7 +427,7 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
         } else if (pUser->type == TSDB_ALTER_USER_PRIVILEGES) {
           assert(pPwd->type == TSDB_DATA_TYPE_NULL);
 
-          SSQLToken* pPrivilege = &pUser->privilege;
+          SStrToken* pPrivilege = &pUser->privilege;
 
           if (strncasecmp(pPrivilege->z, "super", 5) == 0 && pPrivilege->n == 5) {
             pCmd->count = 1;
@@ -487,9 +491,10 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
       const char* msg1 = "columns in select clause not identical";
 
       for (int32_t i = pCmd->numOfClause; i < pInfo->subclauseInfo.numOfClause; ++i) {
-        SQueryInfo* pqi = NULL;
-        if ((code = tscGetQueryInfoDetailSafely(pCmd, i, &pqi)) != TSDB_CODE_SUCCESS) {
-          return code;
+        SQueryInfo* pqi = tscGetQueryInfoDetailSafely(pCmd, i);
+        if (pqi == NULL) {
+          pRes->code = terrno;
+          return pRes->code;
         }
       }
 
@@ -581,7 +586,7 @@ int32_t parseIntervalClause(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SQuerySQL* pQ
   }
 
   // interval is not null
-  SSQLToken* t = &pQuerySql->interval;
+  SStrToken* t = &pQuerySql->interval;
   if (getTimestampInUsFromStr(t->z, t->n, &pQueryInfo->intervalTime) != TSDB_CODE_SUCCESS) {
     return TSDB_CODE_TSC_INVALID_SQL;
   }
@@ -667,7 +672,7 @@ int32_t parseSlidingClause(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SQuerySQL* pQu
   STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
   STableComInfo tinfo = tscGetTableInfo(pTableMetaInfo->pTableMeta);
 
-  SSQLToken* pSliding = &pQuerySql->sliding;
+  SStrToken* pSliding = &pQuerySql->sliding;
   if (pSliding->n != 0) {
     getTimestampInUsFromStr(pSliding->z, pSliding->n, &pQueryInfo->slidingTime);
     if (tinfo.precision == TSDB_TIME_PRECISION_MILLI) {
@@ -692,7 +697,7 @@ int32_t parseSlidingClause(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SQuerySQL* pQu
   return TSDB_CODE_SUCCESS;
 }
 
-int32_t tscSetTableFullName(STableMetaInfo* pTableMetaInfo, SSQLToken* pzTableName, SSqlObj* pSql) {
+int32_t tscSetTableFullName(STableMetaInfo* pTableMetaInfo, SStrToken* pzTableName, SSqlObj* pSql) {
   const char* msg = "name too long";
 
   SSqlCmd* pCmd = &pSql->cmd;
@@ -709,7 +714,7 @@ int32_t tscSetTableFullName(STableMetaInfo* pTableMetaInfo, SSQLToken* pzTableNa
     // db has been specified in sql string so we ignore current db path
     code = setObjFullName(pTableMetaInfo->name, getAccountId(pSql), NULL, pzTableName, NULL);
   } else {  // get current DB name first, then set it into path
-    SSQLToken t = {0};
+    SStrToken t = {0};
     getCurrentDBName(pSql, &t);
 
     code = setObjFullName(pTableMetaInfo->name, NULL, &t, pzTableName, NULL);
@@ -1027,13 +1032,13 @@ static bool has(tFieldList* pFieldList, int32_t startIdx, const char* name) {
 
 static char* getAccountId(SSqlObj* pSql) { return pSql->pTscObj->acctId; }
 
-static void getCurrentDBName(SSqlObj* pSql, SSQLToken* pDBToken) {
+static void getCurrentDBName(SSqlObj* pSql, SStrToken* pDBToken) {
   pDBToken->z = pSql->pTscObj->db;
   pDBToken->n = (uint32_t)strlen(pSql->pTscObj->db);
 }
 
 /* length limitation, strstr cannot be applied */
-static bool hasSpecifyDB(SSQLToken* pTableName) {
+static bool hasSpecifyDB(SStrToken* pTableName) {
   for (uint32_t i = 0; i < pTableName->n; ++i) {
     if (pTableName->z[i] == TS_PATH_DELIMITER[0]) {
       return true;
@@ -1043,7 +1048,7 @@ static bool hasSpecifyDB(SSQLToken* pTableName) {
   return false;
 }
 
-int32_t setObjFullName(char* fullName, const char* account, SSQLToken* pDB, SSQLToken* tableName, int32_t* xlen) {
+int32_t setObjFullName(char* fullName, const char* account, SStrToken* pDB, SStrToken* tableName, int32_t* xlen) {
   int32_t totalLen = 0;
 
   if (account != NULL) {
@@ -1094,18 +1099,6 @@ int32_t setObjFullName(char* fullName, const char* account, SSQLToken* pDB, SSQL
   return (totalLen < TSDB_TABLE_FNAME_LEN) ? TSDB_CODE_SUCCESS : TSDB_CODE_TSC_INVALID_SQL;
 }
 
-static void extractColumnNameFromString(tSQLExprItem* pItem) {
-  if (pItem->pNode->nSQLOptr == TK_STRING) {
-    pItem->pNode->val.nLen = strdequote(pItem->pNode->val.pz);
-    pItem->pNode->nSQLOptr = TK_ID;
-
-    SSQLToken* pIdToken = &pItem->pNode->colInfo;
-    pIdToken->type = TK_ID;
-    pIdToken->z = pItem->pNode->val.pz;
-    pIdToken->n = pItem->pNode->val.nLen;
-  }
-}
-
 static int32_t handleArithmeticExpr(SSqlCmd* pCmd, int32_t clauseIndex, int32_t exprIndex, tSQLExprItem* pItem) {
   const char* msg1 = "invalid column name, or illegal column type";
   const char* msg2 = "invalid arithmetic expression in select clause";
@@ -1123,42 +1116,31 @@ static int32_t handleArithmeticExpr(SSqlCmd* pCmd, int32_t clauseIndex, int32_t
   }
 
   int32_t tableIndex = columnList.ids[0].tableIndex;
-
-  // todo potential data overflow
-  char* arithmeticExprStr = malloc(1024*1024);
-  char* p = arithmeticExprStr;
-
   if (arithmeticType == NORMAL_ARITHMETIC) {
     pQueryInfo->type |= TSDB_QUERY_TYPE_PROJECTION_QUERY;
 
     // all columns in arithmetic expression must belong to the same table
     for (int32_t f = 1; f < columnList.num; ++f) {
       if (columnList.ids[f].tableIndex != tableIndex) {
-        taosTFree(arithmeticExprStr);
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg4);
       }
     }
 
-    if (arithmeticExprToString(pItem->pNode, &p) != TSDB_CODE_SUCCESS) {
-      taosTFree(arithmeticExprStr);
-      return TSDB_CODE_TSC_INVALID_SQL;
-    }
-
     // expr string is set as the parameter of function
     SColumnIndex index = {.tableIndex = tableIndex};
 
     SSqlExpr* pExpr = tscSqlExprAppend(pQueryInfo, TSDB_FUNC_ARITHM, &index, TSDB_DATA_TYPE_DOUBLE, sizeof(double),
                                        sizeof(double), false);
 
-    char* name = (pItem->aliasName != NULL)? pItem->aliasName:arithmeticExprStr;
-    tstrncpy(pExpr->aliasName, name, sizeof(pExpr->aliasName));
+    char* name = (pItem->aliasName != NULL)? pItem->aliasName:pItem->pNode->token.z;
+    size_t len = MIN(sizeof(pExpr->aliasName), pItem->pNode->token.n + 1);
+    tstrncpy(pExpr->aliasName, name, len);
 
     tExprNode* pNode = NULL;
     SArray* colList = taosArrayInit(10, sizeof(SColIndex));
 
     int32_t ret = exprTreeFromSqlExpr(pCmd, &pNode, pItem->pNode, pQueryInfo->exprList, pQueryInfo, colList);
     if (ret != TSDB_CODE_SUCCESS) {
-      taosTFree(arithmeticExprStr);
       taosArrayDestroy(colList);
       tExprTreeDestroy(&pNode, NULL);
       return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg2);
@@ -1167,8 +1149,8 @@ static int32_t handleArithmeticExpr(SSqlCmd* pCmd, int32_t clauseIndex, int32_t
     size_t numOfNode = taosArrayGetSize(colList);
     for(int32_t k = 0; k < numOfNode; ++k) {
       SColIndex* pIndex = taosArrayGet(colList, k);
-      if (pIndex->flag == 1) {
-        taosTFree(arithmeticExprStr);
+      if (TSDB_COL_IS_TAG(pIndex->flag)) {
+        tExprTreeDestroy(&pNode, NULL);
         taosArrayDestroy(colList);
         tExprTreeDestroy(&pNode, NULL);
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg3);
@@ -1185,7 +1167,7 @@ static int32_t handleArithmeticExpr(SSqlCmd* pCmd, int32_t clauseIndex, int32_t
         // TODO: other error handling
       } END_TRY
 
-    size_t len = tbufTell(&bw);
+    len = tbufTell(&bw);
     char* c = tbufGetData(&bw, true);
 
     // set the serialized binary string as the parameter of arithmetic expression
@@ -1196,16 +1178,18 @@ static int32_t handleArithmeticExpr(SSqlCmd* pCmd, int32_t clauseIndex, int32_t
     taosArrayDestroy(colList);
     tExprTreeDestroy(&pNode, NULL);
   } else {
-    if (arithmeticExprToString(pItem->pNode, &p) != TSDB_CODE_SUCCESS) {
-      taosTFree(arithmeticExprStr);
-      return TSDB_CODE_TSC_INVALID_SQL;
-    }
-
     columnList.num = 0;
     columnList.ids[0] = (SColumnIndex) {0, 0};
 
-    char* name = (pItem->aliasName != NULL)? pItem->aliasName:arithmeticExprStr;
-    insertResultField(pQueryInfo, exprIndex, &columnList, sizeof(double), TSDB_DATA_TYPE_DOUBLE, name, NULL);
+    char aliasName[TSDB_COL_NAME_LEN] = {0};
+    if (pItem->aliasName != NULL) {
+      tstrncpy(aliasName, pItem->aliasName, TSDB_COL_NAME_LEN);
+    } else {
+      int32_t nameLen = MIN(TSDB_COL_NAME_LEN, pItem->pNode->token.n + 1);
+      tstrncpy(aliasName, pItem->pNode->token.z, nameLen);
+    }
+
+    insertResultField(pQueryInfo, exprIndex, &columnList, sizeof(double), TSDB_DATA_TYPE_DOUBLE, aliasName, NULL);
 
     int32_t slot = tscNumOfFields(pQueryInfo) - 1;
     SFieldSupInfo* pInfo = tscFieldInfoGetSupp(&pQueryInfo->fieldsInfo, slot);
@@ -1221,7 +1205,6 @@ static int32_t handleArithmeticExpr(SSqlCmd* pCmd, int32_t clauseIndex, int32_t
       int32_t ret = exprTreeFromSqlExpr(pCmd, &pArithExprInfo->pExpr, pItem->pNode, pQueryInfo->exprList, pQueryInfo, NULL);
       if (ret != TSDB_CODE_SUCCESS) {
         tExprTreeDestroy(&pArithExprInfo->pExpr, NULL);
-        taosTFree(arithmeticExprStr);
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), "invalid expression in select clause");
       }
 
@@ -1229,11 +1212,38 @@ static int32_t handleArithmeticExpr(SSqlCmd* pCmd, int32_t clauseIndex, int32_t
     }
   }
 
-  taosTFree(arithmeticExprStr);
   return TSDB_CODE_SUCCESS;
 }
 
-int32_t parseSelectClause(SSqlCmd* pCmd, int32_t clauseIndex, tSQLExprList* pSelection, bool isSTable) {
+static void tscInsertPrimaryTSSourceColumn(SQueryInfo* pQueryInfo, SColumnIndex* pIndex) {
+  SColumnIndex tsCol = {.tableIndex = pIndex->tableIndex, .columnIndex = PRIMARYKEY_TIMESTAMP_COL_INDEX};
+  tscColumnListInsert(pQueryInfo->colList, &tsCol);
+}
+
+static void addProjectQueryCol(SQueryInfo* pQueryInfo, int32_t startPos, SColumnIndex* pIndex, tSQLExprItem* pItem) {
+  SSqlExpr* pExpr = doAddProjectCol(pQueryInfo, startPos, pIndex->columnIndex, pIndex->tableIndex);
+
+  STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, pIndex->tableIndex);
+  STableMeta*     pTableMeta = pTableMetaInfo->pTableMeta;
+
+  SSchema* pSchema = tscGetTableColumnSchema(pTableMeta, pIndex->columnIndex);
+
+  char* colName = (pItem->aliasName == NULL) ? pSchema->name : pItem->aliasName;
+  tstrncpy(pExpr->aliasName, colName, sizeof(pExpr->aliasName));
+
+  SColumnList ids = {0};
+  ids.num = 1;
+  ids.ids[0] = *pIndex;
+
+  if (pIndex->columnIndex == TSDB_TBNAME_COLUMN_INDEX || pIndex->columnIndex == TSDB_UD_COLUMN_INDEX ||
+      pIndex->columnIndex >= tscGetNumOfColumns(pTableMeta)) {
+    ids.num = 0;
+  }
+
+  insertResultField(pQueryInfo, startPos, &ids, pExpr->resBytes, (int8_t)pExpr->resType, pExpr->aliasName, pExpr);
+}
+
+int32_t parseSelectClause(SSqlCmd* pCmd, int32_t clauseIndex, tSQLExprList* pSelection, bool isSTable, bool joinQuery) {
   assert(pSelection != NULL && pCmd != NULL);
 
   const char* msg2 = "functions can not be mixed up";
@@ -1251,16 +1261,14 @@ int32_t parseSelectClause(SSqlCmd* pCmd, int32_t clauseIndex, tSQLExprList* pSel
     tSQLExprItem* pItem = &pSelection->a[i];
 
     // project on all fields
-    if (pItem->pNode->nSQLOptr == TK_ALL || pItem->pNode->nSQLOptr == TK_ID || pItem->pNode->nSQLOptr == TK_STRING) {
+    int32_t optr = pItem->pNode->nSQLOptr;
+
+    if (optr == TK_ALL || optr == TK_ID || optr == TK_STRING || optr == TK_INTEGER || optr == TK_FLOAT) {
       // it is actually a function, but the function name is invalid
       if (pItem->pNode->nSQLOptr == TK_ID && (pItem->pNode->colInfo.z == NULL && pItem->pNode->colInfo.n == 0)) {
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg5);
       }
 
-      // if the name of column is quoted, remove it and set the right information for later process
-      extractColumnNameFromString(pItem);
-      TSDB_QUERY_SET_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_PROJECTION_QUERY);
-
       // select table_name1.field_name1, table_name2.field_name2  from table_name1, table_name2
       if (addProjectionExprAndResultField(pCmd, pQueryInfo, pItem) != TSDB_CODE_SUCCESS) {
         return TSDB_CODE_TSC_INVALID_SQL;
@@ -1276,12 +1284,7 @@ int32_t parseSelectClause(SSqlCmd* pCmd, int32_t clauseIndex, tSQLExprList* pSel
       if (code != TSDB_CODE_SUCCESS) {
         return code;
       }
-
     } else {
-      /*
-       * not support such expression
-       * e.g., select 12+5 from table_name
-       */
       return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg3);
     }
 
@@ -1290,7 +1293,26 @@ int32_t parseSelectClause(SSqlCmd* pCmd, int32_t clauseIndex, tSQLExprList* pSel
     }
   }
 
-  if (!functionCompatibleCheck(pQueryInfo)) {
+  // there is only one user-defined column in the final result field, add the timestamp column.
+  size_t numOfSrcCols = taosArrayGetSize(pQueryInfo->colList);
+  if (numOfSrcCols <= 0 && !tscQueryTags(pQueryInfo)) {
+    SColumnIndex index = {0};
+
+    // set the constant column value always attached to first table.
+    STableMetaInfo* pTableMetaInfo = tscGetTableMetaInfoFromCmd(pCmd, clauseIndex, 0);
+    SSchema* pSchema = tscGetTableColumnSchema(pTableMetaInfo->pTableMeta, PRIMARYKEY_TIMESTAMP_COL_INDEX);
+
+    // add the timestamp column into the output columns
+    int32_t numOfCols = (int32_t)tscSqlExprNumOfExprs(pQueryInfo);
+    tscAddSpecialColumnForSelect(pQueryInfo, numOfCols, TSDB_FUNC_PRJ, &index, pSchema, TSDB_COL_NORMAL);
+
+    SFieldSupInfo* pSupInfo = tscFieldInfoGetSupp(&pQueryInfo->fieldsInfo, numOfCols);
+    pSupInfo->visible = false;
+
+    pQueryInfo->type |= TSDB_QUERY_TYPE_PROJECTION_QUERY;
+  }
+
+  if (!functionCompatibleCheck(pQueryInfo, joinQuery)) {
     return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg2);
   }
 
@@ -1353,32 +1375,10 @@ SSqlExpr* doAddProjectCol(SQueryInfo* pQueryInfo, int32_t outputIndex, int32_t c
       pSchema->bytes, functionId == TSDB_FUNC_TAGPRJ);
 }
 
-static void addProjectQueryCol(SQueryInfo* pQueryInfo, int32_t startPos, SColumnIndex* pIndex, tSQLExprItem* pItem) {
-  SSqlExpr* pExpr = doAddProjectCol(pQueryInfo, startPos, pIndex->columnIndex, pIndex->tableIndex);
-
-  STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, pIndex->tableIndex);
-  STableMeta*     pTableMeta = pTableMetaInfo->pTableMeta;
-  
-  SSchema* pSchema = tscGetTableColumnSchema(pTableMeta, pIndex->columnIndex);
-
-  char* colName = (pItem->aliasName == NULL) ? pSchema->name : pItem->aliasName;
-  tstrncpy(pExpr->aliasName, colName, sizeof(pExpr->aliasName));
-  
-  SColumnList ids = {0};
-  ids.num = 1;
-  ids.ids[0] = *pIndex;
-
-  if (pIndex->columnIndex >= tscGetNumOfColumns(pTableMeta) || pIndex->columnIndex == TSDB_TBNAME_COLUMN_INDEX) {
-    ids.num = 0;
-  }
-
-  insertResultField(pQueryInfo, startPos, &ids, pExpr->resBytes, (int8_t)pExpr->resType, pExpr->aliasName, pExpr);
-}
-
-void tscAddSpecialColumnForSelect(SQueryInfo* pQueryInfo, int32_t outputColIndex, int16_t functionId,
+SSqlExpr* tscAddSpecialColumnForSelect(SQueryInfo* pQueryInfo, int32_t outputColIndex, int16_t functionId,
                                   SColumnIndex* pIndex, SSchema* pColSchema, int16_t flag) {
   SSqlExpr* pExpr = tscSqlExprInsert(pQueryInfo, outputColIndex, functionId, pIndex, pColSchema->type,
-                                     pColSchema->bytes, pColSchema->bytes, flag);
+                                     pColSchema->bytes, pColSchema->bytes, TSDB_COL_IS_TAG(flag));
   tstrncpy(pExpr->aliasName, pColSchema->name, sizeof(pExpr->aliasName));
 
   SColumnList ids = getColumnList(1, pIndex->tableIndex, pIndex->columnIndex);
@@ -1394,6 +1394,8 @@ void tscAddSpecialColumnForSelect(SQueryInfo* pQueryInfo, int32_t outputColIndex
   if (TSDB_COL_IS_TAG(flag)) {
     tscColumnListInsert(pTableMetaInfo->tagColList, pIndex);
   }
+
+  return pExpr;
 }
 
 static int32_t doAddProjectionExprAndResultFields(SQueryInfo* pQueryInfo, SColumnIndex* pIndex, int32_t startPos) {
@@ -1426,18 +1428,16 @@ static int32_t doAddProjectionExprAndResultFields(SQueryInfo* pQueryInfo, SColum
   return numOfTotalColumns;
 }
 
-static void tscInsertPrimaryTSSourceColumn(SQueryInfo* pQueryInfo, SColumnIndex* pIndex) {
-  SColumnIndex tsCol = {.tableIndex = pIndex->tableIndex, .columnIndex = PRIMARYKEY_TIMESTAMP_COL_INDEX};
-  tscColumnListInsert(pQueryInfo->colList, &tsCol);
-}
-
 int32_t addProjectionExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, tSQLExprItem* pItem) {
   const char* msg0 = "invalid column name";
   const char* msg1 = "tag for normal table query is not allowed";
-  
-  int32_t startPos = (int32_t)tscSqlExprNumOfExprs(pQueryInfo);
 
-  if (pItem->pNode->nSQLOptr == TK_ALL) {  // project on all fields
+  int32_t startPos = (int32_t)tscSqlExprNumOfExprs(pQueryInfo);
+  int32_t optr = pItem->pNode->nSQLOptr;
+
+  if (optr == TK_ALL) {  // project on all fields
+    TSDB_QUERY_SET_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_PROJECTION_QUERY);
+
     SColumnIndex index = COLUMN_INDEX_INITIALIZER;
     if (getTableIndexByName(&pItem->pNode->colInfo, pQueryInfo, &index) != TSDB_CODE_SUCCESS) {
       return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg0);
@@ -1453,7 +1453,24 @@ int32_t addProjectionExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, t
     } else {
       doAddProjectionExprAndResultFields(pQueryInfo, &index, startPos);
     }
-  } else if (pItem->pNode->nSQLOptr == TK_ID) {  // simple column projection query
+
+    // add the primary timestamp column even though it is not required by user
+    tscInsertPrimaryTSSourceColumn(pQueryInfo, &index);
+  } else if (optr == TK_STRING || optr == TK_INTEGER || optr == TK_FLOAT) {  // simple column projection query
+    SColumnIndex index = COLUMN_INDEX_INITIALIZER;
+
+    // user-specified constant value as a new result column
+    index.columnIndex = (pQueryInfo->udColumnId--);
+    index.tableIndex = 0;
+
+    SSchema colSchema = tGetUserSpecifiedColumnSchema(&pItem->pNode->val, &pItem->pNode->token, pItem->aliasName);
+    SSqlExpr* pExpr =
+        tscAddSpecialColumnForSelect(pQueryInfo, startPos, TSDB_FUNC_PRJ, &index, &colSchema, TSDB_COL_UDC);
+
+    // NOTE: the first parameter is reserved for the tag column id during join query process.
+    pExpr->numOfParams = 2;
+    tVariantAssign(&pExpr->param[1], &pItem->pNode->val);
+  } else if (optr == TK_ID) {
     SColumnIndex index = COLUMN_INDEX_INITIALIZER;
 
     if (getColumnIndexByName(pCmd, &pItem->pNode->colInfo, pQueryInfo, &index) != TSDB_CODE_SUCCESS) {
@@ -1472,8 +1489,10 @@ int32_t addProjectionExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, t
       }
 
       addProjectQueryCol(pQueryInfo, startPos, &index, pItem);
+      pQueryInfo->type |= TSDB_QUERY_TYPE_PROJECTION_QUERY;
     }
 
+    // add the primary timestamp column even though it is not required by user
     tscInsertPrimaryTSSourceColumn(pQueryInfo, &index);
   } else {
     return TSDB_CODE_TSC_INVALID_SQL;
@@ -1561,7 +1580,7 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
       SColumnIndex index = COLUMN_INDEX_INITIALIZER;
 
       if (pItem->pNode->pParam != NULL) {
-        SSQLToken* pToken = &pItem->pNode->pParam->a[0].pNode->colInfo;
+        SStrToken* pToken = &pItem->pNode->pParam->a[0].pNode->colInfo;
         if (pToken->z == NULL || pToken->n == 0) {
           return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg3);
         }
@@ -1570,7 +1589,7 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
         if (pParamElem->pNode->nSQLOptr == TK_ALL) {
           // select table.*
           // check if the table name is valid or not
-          SSQLToken tmpToken = pParamElem->pNode->colInfo;
+          SStrToken tmpToken = pParamElem->pNode->colInfo;
 
           if (getTableIndexByName(&tmpToken, pQueryInfo, &index) != TSDB_CODE_SUCCESS) {
             return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg4);
@@ -1768,7 +1787,7 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
 
           if (pParamElem->pNode->nSQLOptr == TK_ALL) {
             // select table.*
-            SSQLToken tmpToken = pParamElem->pNode->colInfo;
+            SStrToken tmpToken = pParamElem->pNode->colInfo;
 
             if (getTableIndexByName(&tmpToken, pQueryInfo, &index) != TSDB_CODE_SUCCESS) {
               return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg4);
@@ -1834,10 +1853,11 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
 
           for (int32_t i = 0; i < tscGetNumOfColumns(pTableMetaInfo->pTableMeta); ++i) {
             SColumnIndex index = {.tableIndex = j, .columnIndex = i};
-            if (setExprInfoForFunctions(pCmd, pQueryInfo, pSchema, functionID, pItem->aliasName, colIndex + i + j, &index) !=
-                0) {
+            if (setExprInfoForFunctions(pCmd, pQueryInfo, pSchema, functionID, pItem->aliasName, colIndex, &index) != 0) {
               return TSDB_CODE_TSC_INVALID_SQL;
             }
+
+            colIndex++;
           }
 
           numOfFields += tscGetNumOfColumns(pTableMetaInfo->pTableMeta);
@@ -2045,7 +2065,7 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
 
 // todo refactor
 static SColumnList getColumnList(int32_t num, int16_t tableIndex, int32_t columnIndex) {
-  assert(num == 1 && columnIndex >= -1 && tableIndex >= 0);
+  assert(num == 1 && tableIndex >= 0);
 
   SColumnList columnList = {0};
   columnList.num = num;
@@ -2070,16 +2090,16 @@ void getRevisedName(char* resultFieldName, int32_t functionId, int32_t maxLen, c
   snprintf(resultFieldName, maxLen, "%s(%s)", aAggs[functionId].aName, columnName);
 }
 
-static bool isTablenameToken(SSQLToken* token) {
-  SSQLToken tmpToken = *token;
-  SSQLToken tableToken = {0};
+static bool isTablenameToken(SStrToken* token) {
+  SStrToken tmpToken = *token;
+  SStrToken tableToken = {0};
 
   extractTableNameFromToken(&tmpToken, &tableToken);
 
   return (strncasecmp(TSQL_TBNAME_L, tmpToken.z, tmpToken.n) == 0 && tmpToken.n == strlen(TSQL_TBNAME_L));
 }
 
-static int16_t doGetColumnIndex(SQueryInfo* pQueryInfo, int32_t index, SSQLToken* pToken) {
+static int16_t doGetColumnIndex(SQueryInfo* pQueryInfo, int32_t index, SStrToken* pToken) {
   STableMeta* pTableMeta = tscGetMetaInfo(pQueryInfo, index)->pTableMeta;
 
   int32_t  numOfCols = tscGetNumOfColumns(pTableMeta) + tscGetNumOfTags(pTableMeta);
@@ -2101,7 +2121,7 @@ static int16_t doGetColumnIndex(SQueryInfo* pQueryInfo, int32_t index, SSQLToken
   return columnIndex;
 }
 
-int32_t doGetColumnIndexByName(SSqlCmd* pCmd, SSQLToken* pToken, SQueryInfo* pQueryInfo, SColumnIndex* pIndex) {
+int32_t doGetColumnIndexByName(SSqlCmd* pCmd, SStrToken* pToken, SQueryInfo* pQueryInfo, SColumnIndex* pIndex) {
   const char* msg0 = "ambiguous column name";
   const char* msg1 = "invalid column name";
 
@@ -2143,7 +2163,7 @@ int32_t doGetColumnIndexByName(SSqlCmd* pCmd, SSQLToken* pToken, SQueryInfo* pQu
   }
 }
 
-int32_t getTableIndexImpl(SSQLToken* pTableToken, SQueryInfo* pQueryInfo, SColumnIndex* pIndex) {
+int32_t getTableIndexImpl(SStrToken* pTableToken, SQueryInfo* pQueryInfo, SColumnIndex* pIndex) {
   if (pTableToken->n == 0) {  // only one table and no table name prefix in column name
     if (pQueryInfo->numOfTables == 1) {
       pIndex->tableIndex = 0;
@@ -2169,8 +2189,8 @@ int32_t getTableIndexImpl(SSQLToken* pTableToken, SQueryInfo* pQueryInfo, SColum
   return TSDB_CODE_SUCCESS;
 }
 
-int32_t getTableIndexByName(SSQLToken* pToken, SQueryInfo* pQueryInfo, SColumnIndex* pIndex) {
-  SSQLToken tableToken = {0};
+int32_t getTableIndexByName(SStrToken* pToken, SQueryInfo* pQueryInfo, SColumnIndex* pIndex) {
+  SStrToken tableToken = {0};
   extractTableNameFromToken(pToken, &tableToken);
 
   if (getTableIndexImpl(&tableToken, pQueryInfo, pIndex) != TSDB_CODE_SUCCESS) {
@@ -2180,12 +2200,12 @@ int32_t getTableIndexByName(SSQLToken* pToken, SQueryInfo* pQueryInfo, SColumnIn
   return TSDB_CODE_SUCCESS;
 }
 
-int32_t getColumnIndexByName(SSqlCmd* pCmd, const SSQLToken* pToken, SQueryInfo* pQueryInfo, SColumnIndex* pIndex) {
+int32_t getColumnIndexByName(SSqlCmd* pCmd, const SStrToken* pToken, SQueryInfo* pQueryInfo, SColumnIndex* pIndex) {
   if (pQueryInfo->pTableMetaInfo == NULL || pQueryInfo->numOfTables == 0) {
     return TSDB_CODE_TSC_INVALID_SQL;
   }
 
-  SSQLToken tmpToken = *pToken;
+  SStrToken tmpToken = *pToken;
 
   if (getTableIndexByName(&tmpToken, pQueryInfo, pIndex) != TSDB_CODE_SUCCESS) {
     return TSDB_CODE_TSC_INVALID_SQL;
@@ -2297,7 +2317,7 @@ int32_t setShowInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
   int16_t    showType = pShowInfo->showType;
   if (showType == TSDB_MGMT_TABLE_TABLE || showType == TSDB_MGMT_TABLE_METRIC || showType == TSDB_MGMT_TABLE_VGROUP) {
     // db prefix in tagCond, show table conds in payload
-    SSQLToken* pDbPrefixToken = &pShowInfo->prefix;
+    SStrToken* pDbPrefixToken = &pShowInfo->prefix;
     if (pDbPrefixToken->type != 0) {
 
       if (pDbPrefixToken->n >= TSDB_DB_NAME_LEN) {  // db name is too long
@@ -2319,7 +2339,7 @@ int32_t setShowInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
     }
 
     // show table/stable like 'xxxx', set the like pattern for show tables
-    SSQLToken* pPattern = &pShowInfo->pattern;
+    SStrToken* pPattern = &pShowInfo->pattern;
     if (pPattern->type != 0) {
       pPattern->n = strdequote(pPattern->z);
 
@@ -2337,7 +2357,7 @@ int32_t setShowInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
     }
 
     // show vnodes may be ip addr of dnode in payload
-    SSQLToken* pDnodeIp = &pShowInfo->prefix;
+    SStrToken* pDnodeIp = &pShowInfo->prefix;
     if (pDnodeIp->n >= TSDB_IPv4ADDR_LEN) {  // ip addr is too long
       return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg3);
     }
@@ -2358,7 +2378,7 @@ int32_t setKillInfo(SSqlObj* pSql, struct SSqlInfo* pInfo, int32_t killType) {
   SSqlCmd* pCmd = &pSql->cmd;
   pCmd->command = pInfo->type;
   
-  SSQLToken* idStr = &(pInfo->pDCLInfo->ip);
+  SStrToken* idStr = &(pInfo->pDCLInfo->ip);
   if (idStr->n > TSDB_KILL_MSG_LEN) {
     return TSDB_CODE_TSC_INVALID_SQL;
   }
@@ -2510,7 +2530,7 @@ bool hasUnsupportFunctionsForSTableQuery(SSqlCmd* pCmd, SQueryInfo* pQueryInfo)
   return false;
 }
 
-static bool functionCompatibleCheck(SQueryInfo* pQueryInfo) {
+static bool functionCompatibleCheck(SQueryInfo* pQueryInfo, bool joinQuery) {
   int32_t startIdx = 0;
   
   SSqlExpr* pExpr = tscSqlExprGet(pQueryInfo, startIdx);
@@ -2542,6 +2562,10 @@ static bool functionCompatibleCheck(SQueryInfo* pQueryInfo) {
     if (functionCompatList[functionId] != factor) {
       return false;
     }
+
+    if (functionId == TSDB_FUNC_LAST_ROW && joinQuery) {
+      return false;
+    }
   }
 
   return true;
@@ -2579,7 +2603,7 @@ int32_t parseGroupbyClause(SQueryInfo* pQueryInfo, tVariantList* pList, SSqlCmd*
   
   for (int32_t i = 0; i < pList->nExpr; ++i) {
     tVariant* pVar = &pList->a[i].pVar;
-    SSQLToken token = {pVar->nLen, pVar->nType, pVar->pz};
+    SStrToken token = {pVar->nLen, pVar->nType, pVar->pz};
 
     SColumnIndex index = COLUMN_INDEX_INITIALIZER;
     if (getColumnIndexByName(pCmd, &token, pQueryInfo, &index) != TSDB_CODE_SUCCESS) {
@@ -2659,9 +2683,12 @@ static SColumnFilterInfo* addColumnFilterInfo(SColumn* pColumn) {
   }
 
   int32_t size = pColumn->numOfFilters + 1;
-  char*   tmp = (char*)realloc((void*)(pColumn->filterInfo), sizeof(SColumnFilterInfo) * (size));
+
+  char* tmp = (char*) realloc((void*)(pColumn->filterInfo), sizeof(SColumnFilterInfo) * (size));
   if (tmp != NULL) {
     pColumn->filterInfo = (SColumnFilterInfo*)tmp;
+  } else {
+    return NULL;
   }
 
   pColumn->numOfFilters++;
@@ -2945,9 +2972,16 @@ static int32_t extractColumnFilterInfo(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SC
     } else {  // update the existed column filter information, find the filter info here
       pColFilter = &pColumn->filterInfo[0];
     }
+
+    if (pColFilter == NULL) {
+      return TSDB_CODE_TSC_OUT_OF_MEMORY;
+    }
   } else if (sqlOptr == TK_OR) {
     // TODO fixme: failed to invalid the filter expression: "col1 = 1 OR col2 = 2"
     pColFilter = addColumnFilterInfo(pColumn);
+    if (pColFilter == NULL) {
+      return TSDB_CODE_TSC_OUT_OF_MEMORY;
+    }
   } else {  // error;
     return TSDB_CODE_TSC_INVALID_SQL;
   }
@@ -3072,7 +3106,6 @@ static int32_t getColumnQueryCondInfo(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, tSQ
 
 static int32_t getJoinCondInfo(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, tSQLExpr* pExpr) {
   const char* msg1 = "invalid join query condition";
-  const char* msg2 = "join on binary/nchar not supported";
   const char* msg3 = "type of join columns must be identical";
   const char* msg4 = "invalid column name in join condition";
 
@@ -3116,10 +3149,6 @@ static int32_t getJoinCondInfo(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, tSQLExpr*
     return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg3);
   }
 
-  if (pTagSchema1->type == TSDB_DATA_TYPE_BINARY || pTagSchema1->type == TSDB_DATA_TYPE_NCHAR) {
-    return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg2);
-  }
-
   pTagCond->joinInfo.hasJoin = true;
   return TSDB_CODE_SUCCESS;
 }
@@ -3156,7 +3185,7 @@ int32_t doArithmeticExprToString(tSQLExpr* pExpr, char** exprString) {
   return TSDB_CODE_SUCCESS;
 }
 
-static int32_t arithmeticExprToString(tSQLExpr* pExpr, char** str) {
+static UNUSED_FUNC int32_t arithmeticExprToString(tSQLExpr* pExpr, char** str) {
   char* start = *str;
 
   int32_t code = doArithmeticExprToString(pExpr, str);
@@ -3610,7 +3639,7 @@ static void doExtractExprForSTable(SSqlCmd* pCmd, tSQLExpr** pExpr, SQueryInfo*
       return;
     }
 
-    SSQLToken t = {0};
+    SStrToken t = {0};
     extractTableNameFromToken(&pLeft->colInfo, &t);
 
     *pOut = *pExpr;
@@ -3690,7 +3719,7 @@ static int32_t setTableCondForSTableQuery(SSqlCmd* pCmd, SQueryInfo* pQueryInfo,
   num = j;
 
   char* name = extractDBName(pTableMetaInfo->name, db);
-  SSQLToken dbToken = { .type = TK_STRING, .z = name, .n = (uint32_t)strlen(name) };
+  SStrToken dbToken = { .type = TK_STRING, .z = name, .n = (uint32_t)strlen(name) };
   
   for (int32_t i = 0; i < num; ++i) {
     if (i >= 1) {
@@ -3699,7 +3728,7 @@ static int32_t setTableCondForSTableQuery(SSqlCmd* pCmd, SQueryInfo* pQueryInfo,
 
     char      idBuf[TSDB_TABLE_FNAME_LEN] = {0};
     int32_t   xlen = (int32_t)strlen(segments[i]);
-    SSQLToken t = {.z = segments[i], .n = xlen, .type = TK_STRING};
+    SStrToken t = {.z = segments[i], .n = xlen, .type = TK_STRING};
 
     int32_t ret = setObjFullName(idBuf, account, &dbToken, &t, &xlen);
     if (ret != TSDB_CODE_SUCCESS) {
@@ -4020,7 +4049,7 @@ int32_t getTimeRange(STimeWindow* win, tSQLExpr* pRight, int32_t optr, int16_t t
         return TSDB_CODE_TSC_INVALID_SQL;
       }
     } else {
-      SSQLToken token = {.z = pRight->val.pz, .n = pRight->val.nLen, .type = TK_ID};
+      SStrToken token = {.z = pRight->val.pz, .n = pRight->val.nLen, .type = TK_ID};
       int32_t   len = tSQLGetToken(pRight->val.pz, &token.type);
 
       if ((token.type != TK_INTEGER && token.type != TK_FLOAT) || len != pRight->val.nLen) {
@@ -4266,7 +4295,7 @@ int32_t parseOrderbyClause(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SQuerySQL* pQu
     return TSDB_CODE_SUCCESS;
   }
 
-  SSQLToken    columnName = {pVar->nLen, pVar->nType, pVar->pz};
+  SStrToken    columnName = {pVar->nLen, pVar->nType, pVar->pz};
   SColumnIndex index = {0};
 
   if (UTIL_TABLE_IS_SUPER_TABLE(pTableMetaInfo)) {  // super table query
@@ -4335,7 +4364,7 @@ int32_t parseOrderbyClause(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SQuerySQL* pQu
       }
 
       tVariant* pVar2 = &pSortorder->a[1].pVar;
-      SSQLToken cname = {pVar2->nLen, pVar2->nType, pVar2->pz};
+      SStrToken cname = {pVar2->nLen, pVar2->nType, pVar2->pz};
       if (getColumnIndexByName(pCmd, &cname, pQueryInfo, &index) != TSDB_CODE_SUCCESS) {
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg1);
       }
@@ -4464,7 +4493,7 @@ int32_t setAlterTableInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
     }
 
     SColumnIndex index = COLUMN_INDEX_INITIALIZER;
-    SSQLToken    name = {.z = pItem->pVar.pz, .n = pItem->pVar.nLen, .type = TK_STRING};
+    SStrToken    name = {.z = pItem->pVar.pz, .n = pItem->pVar.nLen, .type = TK_STRING};
 
     if (getColumnIndexByName(pCmd, &name, pQueryInfo, &index) != TSDB_CODE_SUCCESS) {
       return TSDB_CODE_TSC_INVALID_SQL;
@@ -4502,12 +4531,12 @@ int32_t setAlterTableInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
     SColumnIndex srcIndex = COLUMN_INDEX_INITIALIZER;
     SColumnIndex destIndex = COLUMN_INDEX_INITIALIZER;
 
-    SSQLToken srcToken = {.z = pSrcItem->pVar.pz, .n = pSrcItem->pVar.nLen, .type = TK_STRING};
+    SStrToken srcToken = {.z = pSrcItem->pVar.pz, .n = pSrcItem->pVar.nLen, .type = TK_STRING};
     if (getColumnIndexByName(pCmd, &srcToken, pQueryInfo, &srcIndex) != TSDB_CODE_SUCCESS) {
       return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg17);
     }
 
-    SSQLToken destToken = {.z = pDstItem->pVar.pz, .n = pDstItem->pVar.nLen, .type = TK_STRING};
+    SStrToken destToken = {.z = pDstItem->pVar.pz, .n = pDstItem->pVar.nLen, .type = TK_STRING};
     if (getColumnIndexByName(pCmd, &destToken, pQueryInfo, &destIndex) == TSDB_CODE_SUCCESS) {
       return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg19);
     }
@@ -4531,7 +4560,7 @@ int32_t setAlterTableInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
     int16_t       numOfTags = tscGetNumOfTags(pTableMeta);
 
     SColumnIndex columnIndex = COLUMN_INDEX_INITIALIZER;
-    SSQLToken    name = {.type = TK_STRING, .z = pTagName->pz, .n = pTagName->nLen};
+    SStrToken    name = {.type = TK_STRING, .z = pTagName->pz, .n = pTagName->nLen};
     if (getColumnIndexByName(pCmd, &name, pQueryInfo, &columnIndex) != TSDB_CODE_SUCCESS) {
       return TSDB_CODE_TSC_INVALID_SQL;
     }
@@ -4624,7 +4653,7 @@ int32_t setAlterTableInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
     tVariantListItem* pItem = &pAlterSQL->varList->a[0];
 
     SColumnIndex columnIndex = COLUMN_INDEX_INITIALIZER;
-    SSQLToken    name = {.type = TK_STRING, .z = pItem->pVar.pz, .n = pItem->pVar.nLen};
+    SStrToken    name = {.type = TK_STRING, .z = pItem->pVar.pz, .n = pItem->pVar.nLen};
     if (getColumnIndexByName(pCmd, &name, pQueryInfo, &columnIndex) != TSDB_CODE_SUCCESS) {
       return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg17);
     }
@@ -4687,7 +4716,7 @@ int32_t validateFunctionsInIntervalOrGroupbyQuery(SSqlCmd* pCmd, SQueryInfo* pQu
       }
     }
 
-    if (pExpr->functionId == TSDB_FUNC_PRJ || pExpr->functionId == TSDB_FUNC_DIFF ||
+    if ((pExpr->functionId == TSDB_FUNC_PRJ && pExpr->numOfParams == 0) || pExpr->functionId == TSDB_FUNC_DIFF ||
         pExpr->functionId == TSDB_FUNC_ARITHM) {
       isProjectionFunction = true;
     }
@@ -4744,7 +4773,7 @@ int32_t validateDNodeConfig(tDCLSQL* pOptions) {
       {"dDebugFlag", 10}, {"mqttDebugFlag", 13},    {"wDebugFlag", 10}, {"tmrDebugFlag", 12},
   };
 
-  SSQLToken* pOptionToken = &pOptions->a[1];
+  SStrToken* pOptionToken = &pOptions->a[1];
 
   if (pOptions->nTokens == 2) {
     // reset log and reset query cache does not need value
@@ -4756,7 +4785,7 @@ int32_t validateDNodeConfig(tDCLSQL* pOptions) {
     }
   } else if ((strncasecmp(cfgOptions[tokenBalance].name, pOptionToken->z, pOptionToken->n) == 0) &&
              (cfgOptions[tokenBalance].len == pOptionToken->n)) {
-    SSQLToken* pValToken = &pOptions->a[2];
+    SStrToken* pValToken = &pOptions->a[2];
     int32_t vnodeId = 0;
     int32_t dnodeId = 0;
     strdequote(pValToken->z);
@@ -4767,14 +4796,14 @@ int32_t validateDNodeConfig(tDCLSQL* pOptions) {
     return TSDB_CODE_SUCCESS;
   } else if ((strncasecmp(cfgOptions[tokenMonitor].name, pOptionToken->z, pOptionToken->n) == 0) &&
              (cfgOptions[tokenMonitor].len == pOptionToken->n)) {
-    SSQLToken* pValToken = &pOptions->a[2];
+    SStrToken* pValToken = &pOptions->a[2];
     int32_t    val = strtol(pValToken->z, NULL, 10);
     if (val != 0 && val != 1) {
       return TSDB_CODE_TSC_INVALID_SQL;  // options value is invalid
     }
     return TSDB_CODE_SUCCESS;
   } else {
-    SSQLToken* pValToken = &pOptions->a[2];
+    SStrToken* pValToken = &pOptions->a[2];
 
     int32_t val = strtol(pValToken->z, NULL, 10);
     if (val < 0 || val > 256) {
@@ -4803,7 +4832,7 @@ int32_t validateLocalConfig(tDCLSQL* pOptions) {
   SDNodeDynConfOption LOCAL_DYNAMIC_CFG_OPTIONS[6] = {{"resetLog", 8},    {"rpcDebugFlag", 12}, {"tmrDebugFlag", 12},
                                                       {"cDebugFlag", 10}, {"uDebugFlag", 10},   {"debugFlag", 9}};
 
-  SSQLToken* pOptionToken = &pOptions->a[0];
+  SStrToken* pOptionToken = &pOptions->a[0];
 
   if (pOptions->nTokens == 1) {
     // reset log does not need value
@@ -4814,7 +4843,7 @@ int32_t validateLocalConfig(tDCLSQL* pOptions) {
       }
     }
   } else {
-    SSQLToken* pValToken = &pOptions->a[1];
+    SStrToken* pValToken = &pOptions->a[1];
 
     int32_t val = strtol(pValToken->z, NULL, 10);
     if (val < 131 || val > 199) {
@@ -4839,7 +4868,7 @@ int32_t validateColumnName(char* name) {
     return TSDB_CODE_TSC_INVALID_SQL;
   }
 
-  SSQLToken token = {.z = name};
+  SStrToken token = {.z = name};
   token.n = tSQLGetToken(name, &token.type);
 
   if (token.type != TK_STRING && token.type != TK_ID) {
@@ -5018,7 +5047,7 @@ static int32_t setTimePrecision(SSqlCmd* pCmd, SCMCreateDbMsg* pMsg, SCreateDBIn
 
   pMsg->precision = TSDB_TIME_PRECISION_MILLI;  // millisecond by default
 
-  SSQLToken* pToken = &pCreateDbInfo->precision;
+  SStrToken* pToken = &pCreateDbInfo->precision;
   if (pToken->n > 0) {
     pToken->n = strdequote(pToken->z);
 
@@ -5689,7 +5718,7 @@ int32_t doCheckForCreateTable(SSqlObj* pSql, int32_t subClauseIndex, SSqlInfo* p
   assert(pFieldList != NULL);
 
   // if sql specifies db, use it, otherwise use default db
-  SSQLToken* pzTableName = &(pCreateTable->name);
+  SStrToken* pzTableName = &(pCreateTable->name);
 
   if (tscValidateName(pzTableName) != TSDB_CODE_SUCCESS) {
     return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg1);
@@ -5744,7 +5773,7 @@ int32_t doCheckForCreateFromStable(SSqlObj* pSql, SSqlInfo* pInfo) {
   STableMetaInfo* pStableMeterMetaInfo = tscGetMetaInfo(pQueryInfo, STABLE_INDEX);
 
   // super table name, create table by using dst
-  SSQLToken* pToken = &(pCreateTable->usingInfo.stableName);
+  SStrToken* pToken = &(pCreateTable->usingInfo.stableName);
 
   if (tscValidateName(pToken) != TSDB_CODE_SUCCESS) {
     return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg1);
@@ -5837,7 +5866,7 @@ int32_t doCheckForStream(SSqlObj* pSql, SSqlInfo* pInfo) {
   STableMetaInfo*  pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
 
   // if sql specifies db, use it, otherwise use default db
-  SSQLToken* pzTableName = &(pCreateTable->name);
+  SStrToken* pzTableName = &(pCreateTable->name);
   SQuerySQL* pQuerySql = pCreateTable->pSelect;
 
   if (tscValidateName(pzTableName) != TSDB_CODE_SUCCESS) {
@@ -5850,7 +5879,7 @@ int32_t doCheckForStream(SSqlObj* pSql, SSqlInfo* pInfo) {
   }
   
   tVariant* pVar = &pSrcMeterName->a[0].pVar;
-  SSQLToken srcToken = {.z = pVar->pz, .n = pVar->nLen, .type = TK_STRING};
+  SStrToken srcToken = {.z = pVar->pz, .n = pVar->nLen, .type = TK_STRING};
   if (tscValidateName(&srcToken) != TSDB_CODE_SUCCESS) {
     return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg1);
   }
@@ -5865,7 +5894,7 @@ int32_t doCheckForStream(SSqlObj* pSql, SSqlInfo* pInfo) {
   }
 
   bool isSTable = UTIL_TABLE_IS_SUPER_TABLE(pTableMetaInfo);
-  if (parseSelectClause(&pSql->cmd, 0, pQuerySql->pSelection, isSTable) != TSDB_CODE_SUCCESS) {
+  if (parseSelectClause(&pSql->cmd, 0, pQuerySql->pSelection, isSTable, false) != TSDB_CODE_SUCCESS) {
     return TSDB_CODE_TSC_INVALID_SQL;
   }
 
@@ -5991,7 +6020,7 @@ int32_t doCheckForQuery(SSqlObj* pSql, SQuerySQL* pQuerySql, int32_t index) {
 
     pTableItem->nLen = strdequote(pTableItem->pz);
 
-    SSQLToken tableName = {.z = pTableItem->pz, .n = pTableItem->nLen, .type = TK_STRING};
+    SStrToken tableName = {.z = pTableItem->pz, .n = pTableItem->nLen, .type = TK_STRING};
     if (tscValidateName(&tableName) != TSDB_CODE_SUCCESS) {
       return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg0);
     }
@@ -6002,13 +6031,13 @@ int32_t doCheckForQuery(SSqlObj* pSql, SQuerySQL* pQuerySql, int32_t index) {
 
     STableMetaInfo* pTableMetaInfo1 = tscGetMetaInfo(pQueryInfo, i/2);
 
-    SSQLToken t = {.type = TSDB_DATA_TYPE_BINARY, .n = pTableItem->nLen, .z = pTableItem->pz};
+    SStrToken t = {.type = TSDB_DATA_TYPE_BINARY, .n = pTableItem->nLen, .z = pTableItem->pz};
     if (tscSetTableFullName(pTableMetaInfo1, &t, pSql) != TSDB_CODE_SUCCESS) {
       return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg1);
     }
 
     tVariant* pTableItem1 = &pQuerySql->from->a[i + 1].pVar;
-    SSQLToken aliasName = {.z = pTableItem1->pz, .n = pTableItem1->nLen, .type = TK_STRING};
+    SStrToken aliasName = {.z = pTableItem1->pz, .n = pTableItem1->nLen, .type = TK_STRING};
     if (tscValidateName(&aliasName) != TSDB_CODE_SUCCESS) {
       return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg11);
     }
@@ -6048,7 +6077,8 @@ int32_t doCheckForQuery(SSqlObj* pSql, SQuerySQL* pQuerySql, int32_t index) {
     return TSDB_CODE_TSC_INVALID_SQL;
   }
 
-  if (parseSelectClause(pCmd, index, pQuerySql->pSelection, isSTable) != TSDB_CODE_SUCCESS) {
+  int32_t joinQuery = (pQuerySql->from != NULL && pQuerySql->from->nExpr > 2);
+  if (parseSelectClause(pCmd, index, pQuerySql->pSelection, isSTable, joinQuery) != TSDB_CODE_SUCCESS) {
     return TSDB_CODE_TSC_INVALID_SQL;
   }
 
@@ -6082,6 +6112,9 @@ int32_t doCheckForQuery(SSqlObj* pSql, SQuerySQL* pQuerySql, int32_t index) {
     }
   } else {  // set the time rang
     pQueryInfo->window = TSWINDOW_INITIALIZER;
+    if (pQuerySql->from->nExpr > 2) { // it is a join query, no wher clause is not allowed.
+      return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), "condition missing for join query ");
+    }
   }
 
   // user does not specified the query time window, twa is not allowed in such case.
@@ -6131,7 +6164,7 @@ int32_t doCheckForQuery(SSqlObj* pSql, SQuerySQL* pQuerySql, int32_t index) {
     if (pQueryInfo->intervalTime > 0) {
       int64_t timeRange = ABS(pQueryInfo->window.skey - pQueryInfo->window.ekey);
       // number of result is not greater than 10,000,000
-      if ((timeRange == 0) || (timeRange / pQueryInfo->intervalTime) > MAX_RETRIEVE_ROWS_IN_INTERVAL_QUERY) {
+      if ((timeRange == 0) || (timeRange / pQueryInfo->intervalTime) > MAX_INTERVAL_TIME_WINDOW) {
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg6);
       }
     }
@@ -6230,7 +6263,7 @@ int32_t exprTreeFromSqlExpr(SSqlCmd* pCmd, tExprNode **pExpr, const tSQLExpr* pS
     (*pExpr)->_node.pLeft = pLeft;
     (*pExpr)->_node.pRight = pRight;
     
-    SSQLToken t = {.type = pSqlExpr->nSQLOptr};
+    SStrToken t = {.type = pSqlExpr->nSQLOptr};
     (*pExpr)->_node.optr = getBinaryExprOptr(&t);
     
     assert((*pExpr)->_node.optr != 0);
diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index 9282fa74fb..ecb85472fc 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -226,13 +226,17 @@ int tscSendMsgToServer(SSqlObj *pSql) {
       .handle  = &pSql->pRpcCtx,
       .code    = 0
   };
-
   // NOTE: the rpc context should be acquired before sending data to server.
   // Otherwise, the pSql object may have been released already during the response function, which is
   // processMsgFromServer function. In the meanwhile, the assignment of the rpc context to sql object will absolutely
   // cause crash.
-  rpcSendRequest(pObj->pDnodeConn, &pSql->epSet, &rpcMsg);
-  return TSDB_CODE_SUCCESS;
+  if (pObj != NULL && pObj->signature == pObj) {
+    rpcSendRequest(pObj->pDnodeConn, &pSql->epSet, &rpcMsg);
+    return TSDB_CODE_SUCCESS;
+  } else {
+    //pObj->signature has been reset by other thread, ignore concurrency problem
+    return TSDB_CODE_TSC_CONN_KILLED; 
+  }
 }
 
 void tscProcessMsgFromServer(SRpcMsg *rpcMsg, SRpcEpSet *pEpSet) {
@@ -314,10 +318,10 @@ void tscProcessMsgFromServer(SRpcMsg *rpcMsg, SRpcEpSet *pEpSet) {
 
   pRes->rspLen = 0;
   
-  if (pRes->code != TSDB_CODE_TSC_QUERY_CANCELLED) {
-    pRes->code = (rpcMsg->code != TSDB_CODE_SUCCESS) ? rpcMsg->code : TSDB_CODE_RPC_NETWORK_UNAVAIL;
-  } else {
+  if (pRes->code == TSDB_CODE_TSC_QUERY_CANCELLED) {
     tscDebug("%p query is cancelled, code:%s", pSql, tstrerror(pRes->code));
+  } else {
+    pRes->code = rpcMsg->code;
   }
 
   if (pRes->code == TSDB_CODE_SUCCESS) {
@@ -454,35 +458,21 @@ void tscKillSTableQuery(SSqlObj *pSql) {
     return;
   }
 
+  pSql->res.code = TSDB_CODE_TSC_QUERY_CANCELLED;
+
   for (int i = 0; i < pSql->numOfSubs; ++i) {
+    // NOTE: pSub may have been released already here
     SSqlObj *pSub = pSql->pSubs[i];
     if (pSub == NULL) {
       continue;
     }
 
-    /*
-     * here, we cannot set the command = TSDB_SQL_KILL_QUERY. Otherwise, it may cause
-     * sub-queries not correctly released and master sql object of super table query reaches an abnormal state.
-     */
-    rpcCancelRequest(pSub->pRpcCtx);
     pSub->res.code = TSDB_CODE_TSC_QUERY_CANCELLED;
-    tscQueueAsyncRes(pSub);
-  }
-
-  /*
-   * 1. if the subqueries are not launched or partially launched, we need to waiting the launched
-   * query return to successfully free allocated resources.
-   * 2. if no any subqueries are launched yet, which means the super table query only in parse sql stage,
-   * set the res.code, and return.
-   */
-  const int64_t MAX_WAITING_TIME = 10000;  // 10 Sec.
-  int64_t       stime = taosGetTimestampMs();
-
-  while (pCmd->command != TSDB_SQL_RETRIEVE_LOCALMERGE && pCmd->command != TSDB_SQL_RETRIEVE_EMPTY_RESULT) {
-    taosMsleep(100);
-    if (taosGetTimestampMs() - stime > MAX_WAITING_TIME) {
-      break;
+    if (pSub->pRpcCtx != NULL) {
+      rpcCancelRequest(pSub->pRpcCtx);
     }
+
+    tscQueueAsyncRes(pSub); // async res? not other functions?
   }
 
   tscDebug("%p super table query cancelled", pSql);
@@ -638,26 +628,29 @@ int tscBuildQueryMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
 
   if (TSDB_CODE_SUCCESS != tscAllocPayload(pCmd, size)) {
     tscError("%p failed to malloc for query msg", pSql);
-    return -1;  // todo add test for this
+    return TSDB_CODE_TSC_INVALID_SQL;  // todo add test for this
   }
   
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
   STableMetaInfo *pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
   STableMeta * pTableMeta = pTableMetaInfo->pTableMeta;
-  
-  if (taosArrayGetSize(pQueryInfo->colList) <= 0 && !tscQueryTags(pQueryInfo)) {
-    tscError("%p illegal value of numOfCols in query msg: %d", pSql, tscGetNumOfColumns(pTableMeta));
-    return -1;
+
+  size_t numOfSrcCols = taosArrayGetSize(pQueryInfo->colList);
+  if (numOfSrcCols <= 0 && !tscQueryTags(pQueryInfo)) {
+    tscError("%p illegal value of numOfCols in query msg: %"PRIu64", table cols:%d", pSql, numOfSrcCols,
+        tscGetNumOfColumns(pTableMeta));
+
+    return TSDB_CODE_TSC_INVALID_SQL;
   }
   
   if (pQueryInfo->intervalTime < 0) {
     tscError("%p illegal value of aggregation time interval in query msg: %ld", pSql, pQueryInfo->intervalTime);
-    return -1;
+    return TSDB_CODE_TSC_INVALID_SQL;
   }
   
   if (pQueryInfo->groupbyExpr.numOfGroupCols < 0) {
     tscError("%p illegal value of numOfGroupCols in query msg: %d", pSql, pQueryInfo->groupbyExpr.numOfGroupCols);
-    return -1;
+    return TSDB_CODE_TSC_INVALID_SQL;
   }
 
   SQueryTableMsg *pQueryMsg = (SQueryTableMsg *)pCmd->payload;
@@ -735,7 +728,7 @@ int tscBuildQueryMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
 
       if (pColFilter->lowerRelOptr == TSDB_RELATION_INVALID && pColFilter->upperRelOptr == TSDB_RELATION_INVALID) {
         tscError("invalid filter info");
-        return -1;
+        return TSDB_CODE_TSC_INVALID_SQL;
       }
     }
   }
@@ -744,10 +737,10 @@ int tscBuildQueryMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
   for (int32_t i = 0; i < tscSqlExprNumOfExprs(pQueryInfo); ++i) {
     SSqlExpr *pExpr = tscSqlExprGet(pQueryInfo, i);
 
-    if (!tscValidateColumnId(pTableMetaInfo, pExpr->colInfo.colId)) {
+    if (!tscValidateColumnId(pTableMetaInfo, pExpr->colInfo.colId, pExpr->numOfParams)) {
       /* column id is not valid according to the cached table meta, the table meta is expired */
       tscError("%p table schema is not matched with parsed sql", pSql);
-      return -1;
+      return TSDB_CODE_TSC_INVALID_SQL;
     }
 
     pSqlFuncExpr->colInfo.colId    = htons(pExpr->colInfo.colId);
@@ -944,8 +937,8 @@ int32_t tscBuildAcctMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
 
   SCMCreateAcctMsg *pAlterMsg = (SCMCreateAcctMsg *)pCmd->payload;
 
-  SSQLToken *pName = &pInfo->pDCLInfo->user.user;
-  SSQLToken *pPwd = &pInfo->pDCLInfo->user.passwd;
+  SStrToken *pName = &pInfo->pDCLInfo->user.user;
+  SStrToken *pPwd = &pInfo->pDCLInfo->user.passwd;
 
   strncpy(pAlterMsg->user, pName->z, pName->n);
   strncpy(pAlterMsg->pass, pPwd->z, pPwd->n);
@@ -1147,13 +1140,13 @@ int32_t tscBuildShowMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
   pShowMsg->type = pShowInfo->showType;
 
   if (pShowInfo->showType != TSDB_MGMT_TABLE_VNODES) {
-    SSQLToken *pPattern = &pShowInfo->pattern;
+    SStrToken *pPattern = &pShowInfo->pattern;
     if (pPattern->type > 0) {  // only show tables support wildcard query
       strncpy(pShowMsg->payload, pPattern->z, pPattern->n);
       pShowMsg->payloadLen = htons(pPattern->n);
     }
   } else {
-    SSQLToken *pEpAddr = &pShowInfo->prefix;
+    SStrToken *pEpAddr = &pShowInfo->prefix;
     assert(pEpAddr->n > 0 && pEpAddr->type > 0);
 
     strncpy(pShowMsg->payload, pEpAddr->z, pEpAddr->n);
@@ -1295,7 +1288,7 @@ int tscBuildAlterTableMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
   int size = tscEstimateAlterTableMsgLength(pCmd);
   if (TSDB_CODE_SUCCESS != tscAllocPayload(pCmd, size)) {
     tscError("%p failed to malloc for alter table msg", pSql);
-    return -1;
+    return TSDB_CODE_TSC_OUT_OF_MEMORY;
   }
   
   SCMAlterTableMsg *pAlterTableMsg = (SCMAlterTableMsg *)pCmd->payload;
@@ -1443,6 +1436,12 @@ int tscProcessRetrieveLocalMergeRsp(SSqlObj *pSql) {
   SSqlRes *pRes = &pSql->res;
   SSqlCmd *pCmd = &pSql->cmd;
 
+  int32_t code = pRes->code;
+  if (pRes->code != TSDB_CODE_SUCCESS) {
+    tscQueueAsyncRes(pSql);
+    return code;
+  }
+
   pRes->code = tscDoLocalMerge(pSql);
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
 
@@ -1453,7 +1452,7 @@ int tscProcessRetrieveLocalMergeRsp(SSqlObj *pSql) {
   pRes->row = 0;
   pRes->completed = (pRes->numOfRows == 0);
 
-  int32_t code = pRes->code;
+  code = pRes->code;
   if (pRes->code == TSDB_CODE_SUCCESS) {
     (*pSql->fp)(pSql->param, pSql, pRes->numOfRows);
   } else {
@@ -1647,7 +1646,7 @@ int tscBuildHeartBeatMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
   if (TSDB_CODE_SUCCESS != tscAllocPayload(pCmd, size)) {
     pthread_mutex_unlock(&pObj->mutex);
     tscError("%p failed to malloc for heartbeat msg", pSql);
-    return -1;
+    return TSDB_CODE_TSC_OUT_OF_MEMORY;
   }
 
   SCMHeartBeatMsg *pHeartbeat = (SCMHeartBeatMsg *)pCmd->payload;
@@ -1717,7 +1716,7 @@ int tscProcessTableMetaRsp(SSqlObj *pSql) {
   assert(pTableMetaInfo->pTableMeta == NULL);
 
   pTableMetaInfo->pTableMeta = (STableMeta *) taosCachePut(tscCacheHandle, pTableMetaInfo->name,
-      strlen(pTableMetaInfo->name), pTableMeta, size, tsTableMetaKeepTimer);
+      strlen(pTableMetaInfo->name), pTableMeta, size, tsTableMetaKeepTimer * 1000);
   
   // todo handle out of memory case
   if (pTableMetaInfo->pTableMeta == NULL) {
@@ -1921,7 +1920,7 @@ int tscProcessShowRsp(SSqlObj *pSql) {
   STableMeta* pTableMeta = tscCreateTableMetaFromMsg(pMetaMsg, &size);
   
   pTableMetaInfo->pTableMeta = taosCachePut(tscCacheHandle, key, strlen(key), (char *)pTableMeta, size,
-      tsTableMetaKeepTimer);
+      tsTableMetaKeepTimer * 1000);
   SSchema *pTableSchema = tscGetTableSchema(pTableMetaInfo->pTableMeta);
 
   if (pQueryInfo->colList == NULL) {
@@ -1961,8 +1960,12 @@ static void createHBObj(STscObj* pObj) {
 
   pSql->fp = tscProcessHeartBeatRsp;
 
-  SQueryInfo *pQueryInfo = NULL;
-  tscGetQueryInfoDetailSafely(&pSql->cmd, 0, &pQueryInfo);
+  SQueryInfo *pQueryInfo = tscGetQueryInfoDetailSafely(&pSql->cmd, 0);
+  if (pQueryInfo == NULL) {
+    pSql->res.code = terrno;
+    return;
+  }
+
   pQueryInfo->command = TSDB_SQL_HB;
 
   pSql->cmd.command = pQueryInfo->command;
@@ -2147,8 +2150,7 @@ static int32_t getTableMetaFromMgmt(SSqlObj *pSql, STableMetaInfo *pTableMetaInf
 
   tscAddSubqueryInfo(&pNew->cmd);
 
-  SQueryInfo *pNewQueryInfo = NULL;
-  tscGetQueryInfoDetailSafely(&pNew->cmd, 0, &pNewQueryInfo);
+  SQueryInfo *pNewQueryInfo = tscGetQueryInfoDetailSafely(&pNew->cmd, 0);
 
   pNew->cmd.autoCreated = pSql->cmd.autoCreated;  // create table if not exists
   if (TSDB_CODE_SUCCESS != tscAllocPayload(&pNew->cmd, TSDB_DEFAULT_PAYLOAD_SIZE + pSql->cmd.payloadLen)) {
@@ -2251,8 +2253,8 @@ int tscGetSTableVgroupInfo(SSqlObj *pSql, int32_t clauseIndex) {
 
   pNew->cmd.command = TSDB_SQL_STABLEVGROUP;
   
-  SQueryInfo *pNewQueryInfo = NULL;
-  if ((code = tscGetQueryInfoDetailSafely(&pNew->cmd, 0, &pNewQueryInfo)) != TSDB_CODE_SUCCESS) {
+  SQueryInfo *pNewQueryInfo = tscGetQueryInfoDetailSafely(&pNew->cmd, 0);
+  if (pNewQueryInfo == NULL) {
     tscFreeSqlObj(pNew);
     return code;
   }
diff --git a/src/client/src/tscSql.c b/src/client/src/tscSql.c
index de998a6b59..f63923e046 100644
--- a/src/client/src/tscSql.c
+++ b/src/client/src/tscSql.c
@@ -655,27 +655,30 @@ int* taos_fetch_lengths(TAOS_RES *res) {
 char *taos_get_client_info() { return version; }
 
 void taos_stop_query(TAOS_RES *res) {
-  if (res == NULL) {
+  SSqlObj *pSql = (SSqlObj *)res;
+  if (pSql == NULL || pSql->signature != pSql) {
     return;
   }
 
-  SSqlObj *pSql = (SSqlObj *)res;
+  tscDebug("%p start to cancel query", res);
   SSqlCmd *pCmd = &pSql->cmd;
 
-  if (pSql->signature != pSql) return;
-  tscDebug("%p start to cancel query", res);
-
-
+  // TODO there are multi-thread problem.
+  // It may have been released by the other thread already.
+  // The ref count may fix this problem.
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
-  if (tscIsTwoStageSTableQuery(pQueryInfo, 0)) {
-    tscKillSTableQuery(pSql);
-  }
 
-  if (pSql->cmd.command < TSDB_SQL_LOCAL) {
-    rpcCancelRequest(pSql->pRpcCtx);
-  }
+  // set the error code for master pSqlObj firstly
   pSql->res.code = TSDB_CODE_TSC_QUERY_CANCELLED;
-  tscQueueAsyncRes(pSql);
+
+  if (tscIsTwoStageSTableQuery(pQueryInfo, 0)) {
+    assert(pSql->pRpcCtx == NULL);
+    tscKillSTableQuery(pSql);
+  } else {
+    if (pSql->cmd.command < TSDB_SQL_LOCAL) {
+      rpcCancelRequest(pSql->pRpcCtx);
+    }
+  }
 
   tscDebug("%p query is cancelled", res);
 }
@@ -824,8 +827,11 @@ static int tscParseTblNameList(SSqlObj *pSql, const char *tblNameList, int32_t t
   int   code = TSDB_CODE_TSC_INVALID_TABLE_ID_LENGTH;
   char *str = (char *)tblNameList;
 
-  SQueryInfo *pQueryInfo = NULL;
-  tscGetQueryInfoDetailSafely(pCmd, pCmd->clauseIndex, &pQueryInfo);
+  SQueryInfo *pQueryInfo = tscGetQueryInfoDetailSafely(pCmd, pCmd->clauseIndex);
+  if (pQueryInfo == NULL) {
+    pSql->res.code = terrno;
+    return terrno;
+  }
 
   STableMetaInfo *pTableMetaInfo = tscAddEmptyMetaInfo(pQueryInfo);
 
@@ -850,7 +856,7 @@ static int tscParseTblNameList(SSqlObj *pSql, const char *tblNameList, int32_t t
     str = nextStr + 1;
     len = (int32_t)strtrim(tblName);
 
-    SSQLToken sToken = {.n = len, .type = TK_ID, .z = tblName};
+    SStrToken sToken = {.n = len, .type = TK_ID, .z = tblName};
     tSQLGetToken(tblName, &sToken.type);
 
     // Check if the table name available or not
diff --git a/src/client/src/tscSubquery.c b/src/client/src/tscSubquery.c
index c022e320a3..2fb264c756 100644
--- a/src/client/src/tscSubquery.c
+++ b/src/client/src/tscSubquery.c
@@ -95,13 +95,14 @@ static int64_t doTSBlockIntersect(SSqlObj* pSql, SJoinSupporter* pSupporter1, SJ
     tscInfo("%" PRId64 ", tags:%d \t %" PRId64 ", tags:%d", elem1.ts, elem1.tag, elem2.ts, elem2.tag);
 #endif
 
-    if (elem1.tag < elem2.tag || (elem1.tag == elem2.tag && tsCompare(order, elem1.ts, elem2.ts))) {
+    int32_t res = tVariantCompare(&elem1.tag, &elem2.tag);
+    if (res == -1 || (res == 0 && tsCompare(order, elem1.ts, elem2.ts))) {
       if (!tsBufNextPos(pSupporter1->pTSBuf)) {
         break;
       }
 
       numOfInput1++;
-    } else if (elem1.tag > elem2.tag || (elem1.tag == elem2.tag && tsCompare(order, elem2.ts, elem1.ts))) {
+    } else if ((res > 0) || (res == 0 && tsCompare(order, elem2.ts, elem1.ts))) {
       if (!tsBufNextPos(pSupporter2->pTSBuf)) {
         break;
       }
@@ -121,8 +122,8 @@ static int64_t doTSBlockIntersect(SSqlObj* pSql, SJoinSupporter* pSupporter1, SJ
           win->ekey = elem1.ts;
         }
         
-        tsBufAppend(output1, elem1.vnode, elem1.tag, (const char*)&elem1.ts, sizeof(elem1.ts));
-        tsBufAppend(output2, elem2.vnode, elem2.tag, (const char*)&elem2.ts, sizeof(elem2.ts));
+        tsBufAppend(output1, elem1.vnode, &elem1.tag, (const char*)&elem1.ts, sizeof(elem1.ts));
+        tsBufAppend(output2, elem2.vnode, &elem2.tag, (const char*)&elem2.ts, sizeof(elem2.ts));
       } else {
         pLimit->offset -= 1;
       }
@@ -354,11 +355,12 @@ static int32_t tscLaunchRealSubqueries(SSqlObj* pSql) {
       pExpr = tscSqlExprGet(pQueryInfo, 0);
     }
 
-    // set the join condition tag column info, to do extract method
+    // set the join condition tag column info, todo extract method
     if (UTIL_TABLE_IS_SUPER_TABLE(pTableMetaInfo)) {
       assert(pQueryInfo->tagCond.joinInfo.hasJoin);
       int16_t colId = tscGetJoinTagColIdByUid(&pQueryInfo->tagCond, pTableMetaInfo->pTableMeta->id.uid);
 
+      // set the tag column id for executor to extract correct tag value
       pExpr->param[0].i64Key = colId;
       pExpr->numOfParams = 1;
     }
@@ -435,6 +437,7 @@ int32_t tscCompareTidTags(const void* p1, const void* p2) {
   if (t1->vgId != t2->vgId) {
     return (t1->vgId > t2->vgId) ? 1 : -1;
   }
+
   if (t1->tid != t2->tid) {
     return (t1->tid > t2->tid) ? 1 : -1;
   }
@@ -541,6 +544,7 @@ static bool checkForDuplicateTagVal(SQueryInfo* pQueryInfo, SJoinSupporter* p1,
   for(int32_t i = 1; i < p1->num; ++i) {
     STidTags* prev = (STidTags*) varDataVal(p1->pIdTagList + (i - 1) * p1->tagSize);
     STidTags* p = (STidTags*) varDataVal(p1->pIdTagList + i * p1->tagSize);
+    assert(prev->vgId >= 1 && p->vgId >= 1);
 
     if (doCompare(prev->tag, p->tag, pColSchema->type, pColSchema->bytes) == 0) {
       tscError("%p join tags have same value for different table, free all sub SqlObj and quit", pPSqlObj);
@@ -577,6 +581,7 @@ static int32_t getIntersectionOfTableTuple(SQueryInfo* pQueryInfo, SSqlObj* pPar
   while(i < p1->num && j < p2->num) {
     STidTags* pp1 = (STidTags*) varDataVal(p1->pIdTagList + i * p1->tagSize);
     STidTags* pp2 = (STidTags*) varDataVal(p2->pIdTagList + j * p2->tagSize);
+    assert(pp1->tid != 0 && pp2->tid != 0);
 
     int32_t ret = doCompare(pp1->tag, pp2->tag, pColSchema->type, pColSchema->bytes);
     if (ret == 0) {
@@ -686,6 +691,7 @@ static void tidTagRetrieveCallback(void* param, TAOS_RES* tres, int32_t numOfRow
     freeJoinSubqueryObj(pParentSql);
     pParentSql->res.code = code;
     tscQueueAsyncRes(pParentSql);
+
     taosArrayDestroy(s1);
     taosArrayDestroy(s2);
     return;
@@ -1145,7 +1151,7 @@ void tscJoinQueryCallback(void* param, TAOS_RES* tres, int code) {
 /////////////////////////////////////////////////////////////////////////////////////////
 static void tscRetrieveDataRes(void *param, TAOS_RES *tres, int code);
 
-static SSqlObj *tscCreateSqlObjForSubquery(SSqlObj *pSql, SRetrieveSupport *trsupport, SSqlObj *prevSqlObj);
+static SSqlObj *tscCreateSTableSubquery(SSqlObj *pSql, SRetrieveSupport *trsupport, SSqlObj *prevSqlObj);
 
 int32_t tscLaunchJoinSubquery(SSqlObj *pSql, int16_t tableIndex, SJoinSupporter *pSupporter) {
   SSqlCmd *   pCmd = &pSql->cmd;
@@ -1218,6 +1224,16 @@ int32_t tscLaunchJoinSubquery(SSqlObj *pSql, int16_t tableIndex, SJoinSupporter
       int32_t tagColId = tscGetJoinTagColIdByUid(pTagCond, pTableMetaInfo->pTableMeta->id.uid);
       SSchema* s = tscGetTableColumnSchemaById(pTableMetaInfo->pTableMeta, tagColId);
 
+      // get the tag colId column index
+      int32_t numOfTags = tscGetNumOfTags(pTableMetaInfo->pTableMeta);
+      SSchema* pSchema = tscGetTableTagSchema(pTableMetaInfo->pTableMeta);
+      for(int32_t i = 0; i < numOfTags; ++i) {
+        if (pSchema[i].colId == tagColId) {
+          index.columnIndex = i;
+          break;
+        }
+      }
+
       int16_t bytes = 0;
       int16_t type  = 0;
       int32_t inter = 0;
@@ -1287,8 +1303,14 @@ int32_t tscHandleMasterJoinQuery(SSqlObj* pSql) {
   SSqlCmd* pCmd = &pSql->cmd;
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
   assert((pQueryInfo->type & TSDB_QUERY_TYPE_SUBQUERY) == 0);
-  
+
+  // todo add test
   SSubqueryState *pState = calloc(1, sizeof(SSubqueryState));
+  if (pState == NULL) {
+    pSql->res.code = TSDB_CODE_TSC_OUT_OF_MEMORY;
+    return pSql->res.code;
+  }
+
   pState->numOfTotal = pQueryInfo->numOfTables;
   pState->numOfRemain = pState->numOfTotal;
 
@@ -1302,7 +1324,7 @@ int32_t tscHandleMasterJoinQuery(SSqlObj* pSql) {
       pSql->res.code = TSDB_CODE_TSC_OUT_OF_MEMORY;
       if (0 == i) {
         taosTFree(pState);
-      } 
+      }
       return pSql->res.code;
     }
     
@@ -1332,10 +1354,6 @@ static void doCleanupSubqueries(SSqlObj *pSql, int32_t numOfSubs, SSubqueryState
     SRetrieveSupport* pSupport = pSub->param;
     
     taosTFree(pSupport->localBuffer);
-    
-    pthread_mutex_unlock(&pSupport->queryMutex);
-    pthread_mutex_destroy(&pSupport->queryMutex);
-    
     taosTFree(pSupport);
     
     tscFreeSqlObj(pSub);
@@ -1408,14 +1426,7 @@ int32_t tscHandleMasterSTableQuery(SSqlObj *pSql) {
     trs->pParentSql = pSql;
     trs->pFinalColModel = pModel;
     
-    pthread_mutexattr_t mutexattr;
-    memset(&mutexattr, 0, sizeof(pthread_mutexattr_t));
-
-    pthread_mutexattr_settype(&mutexattr, PTHREAD_MUTEX_RECURSIVE_NP);
-    pthread_mutex_init(&trs->queryMutex, &mutexattr);
-    pthread_mutexattr_destroy(&mutexattr);
-    
-    SSqlObj *pNew = tscCreateSqlObjForSubquery(pSql, trs, NULL);
+    SSqlObj *pNew = tscCreateSTableSubquery(pSql, trs, NULL);
     if (pNew == NULL) {
       tscError("%p failed to malloc buffer for subObj, orderOfSub:%d, reason:%s", pSql, i, strerror(errno));
       taosTFree(trs->localBuffer);
@@ -1460,15 +1471,16 @@ int32_t tscHandleMasterSTableQuery(SSqlObj *pSql) {
 }
 
 static void tscFreeSubSqlObj(SRetrieveSupport *trsupport, SSqlObj *pSql) {
-  tscDebug("%p start to free subquery result", pSql);
-  
+  tscDebug("%p start to free subquery obj", pSql);
+
+  int32_t  index = trsupport->subqueryIndex;
+  SSqlObj *pParentSql = trsupport->pParentSql;
+
+  assert(pSql == pParentSql->pSubs[index]);
+  pParentSql->pSubs[index] = NULL;
+
   taos_free_result(pSql);
-  
   taosTFree(trsupport->localBuffer);
-  
-  pthread_mutex_unlock(&trsupport->queryMutex);
-  pthread_mutex_destroy(&trsupport->queryMutex);
-  
   taosTFree(trsupport);
 }
 
@@ -1477,23 +1489,11 @@ static void tscHandleSubqueryError(SRetrieveSupport *trsupport, SSqlObj *pSql, i
 
 static void tscAbortFurtherRetryRetrieval(SRetrieveSupport *trsupport, TAOS_RES *tres, int32_t code) {
 // set no disk space error info
-#ifdef WINDOWS
-  LPVOID lpMsgBuf;
-  FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL,
-                GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),  // Default language
-                (LPTSTR)&lpMsgBuf, 0, NULL);
-  tscError("sub:%p failed to flush data to disk:reason:%s", tres, lpMsgBuf);
-  LocalFree(lpMsgBuf);
-#else
   tscError("sub:%p failed to flush data to disk, reason:%s", tres, tstrerror(code));
-#endif
-
   SSqlObj* pParentSql = trsupport->pParentSql;
 
   pParentSql->res.code = code;
   trsupport->numOfRetry = MAX_NUM_OF_SUBQUERY_RETRY;
-  
-  pthread_mutex_unlock(&trsupport->queryMutex);
   tscHandleSubqueryError(trsupport, tres, pParentSql->res.code);
 }
 
@@ -1512,13 +1512,10 @@ static int32_t tscReissueSubquery(SRetrieveSupport *trsupport, SSqlObj *pSql, in
 
   // clear local saved number of results
   trsupport->localBuffer->num = 0;
-  pthread_mutex_unlock(&trsupport->queryMutex);
-
-  tscTrace("%p sub:%p retrieve failed, code:%s, orderOfSub:%d, retry:%d", trsupport->pParentSql, pSql,
+  tscError("%p sub:%p retrieve/query failed, code:%s, orderOfSub:%d, retry:%d", trsupport->pParentSql, pSql,
            tstrerror(code), subqueryIndex, trsupport->numOfRetry);
 
-  SSqlObj *pNew = tscCreateSqlObjForSubquery(trsupport->pParentSql, trsupport, pSql);
-
+  SSqlObj *pNew = tscCreateSTableSubquery(trsupport->pParentSql, trsupport, pSql);
   if (pNew == NULL) {
     tscError("%p sub:%p failed to create new subquery due to error:%s, abort retry, vgId:%d, orderOfSub:%d",
              trsupport->pParentSql, pSql, tstrerror(terrno), pVgroup->vgId, trsupport->subqueryIndex);
@@ -1529,8 +1526,15 @@ static int32_t tscReissueSubquery(SRetrieveSupport *trsupport, SSqlObj *pSql, in
     return pParentSql->res.code;
   }
 
-  taos_free_result(pSql);
-  return tscProcessSql(pNew);
+  int32_t ret = tscProcessSql(pNew);
+
+  // if failed to process sql, let following code handle the pSql
+  if (ret == TSDB_CODE_SUCCESS) {
+    taos_free_result(pSql);
+    return ret;
+  } else {
+    return ret;
+  }
 }
 
 void tscHandleSubqueryError(SRetrieveSupport *trsupport, SSqlObj *pSql, int numOfRows) {
@@ -1550,14 +1554,14 @@ void tscHandleSubqueryError(SRetrieveSupport *trsupport, SSqlObj *pSql, int numO
      */
     pSql->res.numOfRows = 0;
     trsupport->numOfRetry = MAX_NUM_OF_SUBQUERY_RETRY;  // disable retry efforts
-    tscDebug("%p query is cancelled, sub:%p, orderOfSub:%d abort retrieve, code:%d", pParentSql, pSql,
-             subqueryIndex, pParentSql->res.code);
+    tscDebug("%p query is cancelled, sub:%p, orderOfSub:%d abort retrieve, code:%s", pParentSql, pSql,
+             subqueryIndex, tstrerror(pParentSql->res.code));
   }
 
   if (numOfRows >= 0) {  // current query is successful, but other sub query failed, still abort current query.
     tscDebug("%p sub:%p retrieve numOfRows:%d,orderOfSub:%d", pParentSql, pSql, numOfRows, subqueryIndex);
-    tscError("%p sub:%p abort further retrieval due to other queries failure,orderOfSub:%d,code:%d", pParentSql, pSql,
-             subqueryIndex, pParentSql->res.code);
+    tscError("%p sub:%p abort further retrieval due to other queries failure,orderOfSub:%d,code:%s", pParentSql, pSql,
+             subqueryIndex, tstrerror(pParentSql->res.code));
   } else {
     if (trsupport->numOfRetry++ < MAX_NUM_OF_SUBQUERY_RETRY && pParentSql->res.code == TSDB_CODE_SUCCESS) {
       if (tscReissueSubquery(trsupport, pSql, numOfRows) == TSDB_CODE_SUCCESS) {
@@ -1589,10 +1593,10 @@ void tscHandleSubqueryError(SRetrieveSupport *trsupport, SSqlObj *pSql, int numO
   
   taosTFree(trsupport->pState);
   tscFreeSubSqlObj(trsupport, pSql);
-  
+
   // in case of second stage join subquery, invoke its callback function instead of regular QueueAsyncRes
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(&pParentSql->cmd, 0);
-  
+
   if (!TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_JOIN_SEC_STAGE)) {
     (*pParentSql->fp)(pParentSql->param, pParentSql, pParentSql->res.code);
   } else {  // regular super table query
@@ -1671,7 +1675,7 @@ static void tscAllDataRetrievedFromDnode(SRetrieveSupport *trsupport, SSqlObj* p
   // only free once
   taosTFree(trsupport->pState);
   tscFreeSubSqlObj(trsupport, pSql);
-  
+
   // set the command flag must be after the semaphore been correctly set.
   pParentSql->cmd.command = TSDB_SQL_RETRIEVE_LOCALMERGE;
   if (pParentSql->res.code == TSDB_CODE_SUCCESS) {
@@ -1687,24 +1691,22 @@ static void tscRetrieveFromDnodeCallBack(void *param, TAOS_RES *tres, int numOfR
   int32_t           idx   = trsupport->subqueryIndex;
   SSqlObj *         pParentSql = trsupport->pParentSql;
 
+  assert(tres != NULL);
   SSqlObj *pSql = (SSqlObj *)tres;
-  if (pSql == NULL) {  // sql object has been released in error process, return immediately
-    tscDebug("%p subquery has been released, idx:%d, abort", pParentSql, idx);
-    return;
-  }
-  
+//  if (pSql == NULL) {  // sql object has been released in error process, return immediately
+//    tscDebug("%p subquery has been released, idx:%d, abort", pParentSql, idx);
+//    return;
+//  }
+
   SSubqueryState* pState = trsupport->pState;
   assert(pState->numOfRemain <= pState->numOfTotal && pState->numOfRemain >= 0 && pParentSql->numOfSubs == pState->numOfTotal);
   
-  // query process and cancel query process may execute at the same time
-  pthread_mutex_lock(&trsupport->queryMutex);
-
   STableMetaInfo *pTableMetaInfo = tscGetTableMetaInfoFromCmd(&pSql->cmd, 0, 0);
-  SCMVgroupInfo* pVgroup = &pTableMetaInfo->vgroupList->vgroups[0];
+  SCMVgroupInfo  *pVgroup = &pTableMetaInfo->vgroupList->vgroups[0];
 
   if (pParentSql->res.code != TSDB_CODE_SUCCESS) {
     trsupport->numOfRetry = MAX_NUM_OF_SUBQUERY_RETRY;
-    tscTrace("%p query cancelled or failed, sub:%p, vgId:%d, orderOfSub:%d, code:%s, global code:%s",
+    tscDebug("%p query cancelled/failed, sub:%p, vgId:%d, orderOfSub:%d, code:%s, global code:%s",
              pParentSql, pSql, pVgroup->vgId, trsupport->subqueryIndex, tstrerror(numOfRows), tstrerror(pParentSql->res.code));
 
     tscHandleSubqueryError(param, tres, numOfRows);
@@ -1715,13 +1717,13 @@ static void tscRetrieveFromDnodeCallBack(void *param, TAOS_RES *tres, int numOfR
     assert(numOfRows == taos_errno(pSql));
 
     if (trsupport->numOfRetry++ < MAX_NUM_OF_SUBQUERY_RETRY) {
-      tscTrace("%p sub:%p failed code:%s, retry:%d", pParentSql, pSql, tstrerror(numOfRows), trsupport->numOfRetry);
+      tscError("%p sub:%p failed code:%s, retry:%d", pParentSql, pSql, tstrerror(numOfRows), trsupport->numOfRetry);
 
       if (tscReissueSubquery(trsupport, pSql, numOfRows) == TSDB_CODE_SUCCESS) {
         return;
       }
     } else {
-      tscTrace("%p sub:%p reach the max retry times, set global code:%s", pParentSql, pSql, tstrerror(numOfRows));
+      tscDebug("%p sub:%p reach the max retry times, set global code:%s", pParentSql, pSql, tstrerror(numOfRows));
       atomic_val_compare_exchange_32(&pParentSql->res.code, TSDB_CODE_SUCCESS, numOfRows);  // set global code and abort
     }
 
@@ -1766,13 +1768,9 @@ static void tscRetrieveFromDnodeCallBack(void *param, TAOS_RES *tres, int numOfR
                                (int32_t)pRes->numOfRows, pQueryInfo->groupbyExpr.orderType);
     if (ret != 0) { // set no disk space error info, and abort retry
       tscAbortFurtherRetryRetrieval(trsupport, tres, TSDB_CODE_TSC_NO_DISKSPACE);
-      
     } else if (pRes->completed) {
       tscAllDataRetrievedFromDnode(trsupport, pSql);
-      return;
-      
     } else { // continue fetch data from dnode
-      pthread_mutex_unlock(&trsupport->queryMutex);
       taos_fetch_rows_a(tres, tscRetrieveFromDnodeCallBack, param);
     }
     
@@ -1781,15 +1779,15 @@ static void tscRetrieveFromDnodeCallBack(void *param, TAOS_RES *tres, int numOfR
   }
 }
 
-static SSqlObj *tscCreateSqlObjForSubquery(SSqlObj *pSql, SRetrieveSupport *trsupport, SSqlObj *prevSqlObj) {
+static SSqlObj *tscCreateSTableSubquery(SSqlObj *pSql, SRetrieveSupport *trsupport, SSqlObj *prevSqlObj) {
   const int32_t table_index = 0;
   
   SSqlObj *pNew = createSubqueryObj(pSql, table_index, tscRetrieveDataRes, trsupport, TSDB_SQL_SELECT, prevSqlObj);
   if (pNew != NULL) {  // the sub query of two-stage super table query
     SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(&pNew->cmd, 0);
+
     pQueryInfo->type |= TSDB_QUERY_TYPE_STABLE_SUBQUERY;
-    
-    assert(pQueryInfo->numOfTables == 1 && pNew->cmd.numOfClause == 1);
+    assert(pQueryInfo->numOfTables == 1 && pNew->cmd.numOfClause == 1 && trsupport->subqueryIndex < pSql->numOfSubs);
     
     // launch subquery for each vnode, so the subquery index equals to the vgroupIndex.
     STableMetaInfo *pTableMetaInfo = tscGetMetaInfo(pQueryInfo, table_index);
@@ -1806,7 +1804,7 @@ void tscRetrieveDataRes(void *param, TAOS_RES *tres, int code) {
   
   SSqlObj*  pParentSql = trsupport->pParentSql;
   SSqlObj*  pSql = (SSqlObj *) tres;
-  
+
   SQueryInfo* pQueryInfo = tscGetQueryInfoDetail(&pSql->cmd, 0);
   assert(pSql->cmd.numOfClause == 1 && pQueryInfo->numOfTables == 1);
   
@@ -1816,7 +1814,7 @@ void tscRetrieveDataRes(void *param, TAOS_RES *tres, int code) {
   // stable query killed or other subquery failed, all query stopped
   if (pParentSql->res.code != TSDB_CODE_SUCCESS) {
     trsupport->numOfRetry = MAX_NUM_OF_SUBQUERY_RETRY;
-    tscTrace("%p query cancelled or failed, sub:%p, vgId:%d, orderOfSub:%d, code:%s, global code:%s",
+    tscError("%p query cancelled or failed, sub:%p, vgId:%d, orderOfSub:%d, code:%s, global code:%s",
         pParentSql, pSql, pVgroup->vgId, trsupport->subqueryIndex, tstrerror(code), tstrerror(pParentSql->res.code));
 
     tscHandleSubqueryError(param, tres, code);
@@ -1834,12 +1832,12 @@ void tscRetrieveDataRes(void *param, TAOS_RES *tres, int code) {
     assert(code == taos_errno(pSql));
 
     if (trsupport->numOfRetry++ < MAX_NUM_OF_SUBQUERY_RETRY) {
-      tscTrace("%p sub:%p failed code:%s, retry:%d", pParentSql, pSql, tstrerror(code), trsupport->numOfRetry);
+      tscError("%p sub:%p failed code:%s, retry:%d", pParentSql, pSql, tstrerror(code), trsupport->numOfRetry);
       if (tscReissueSubquery(trsupport, pSql, code) == TSDB_CODE_SUCCESS) {
         return;
       }
     } else {
-      tscTrace("%p sub:%p reach the max retry times, set global code:%s", pParentSql, pSql, tstrerror(code));
+      tscError("%p sub:%p reach the max retry times, set global code:%s", pParentSql, pSql, tstrerror(code));
       atomic_val_compare_exchange_32(&pParentSql->res.code, TSDB_CODE_SUCCESS, code);  // set global code and abort
     }
 
@@ -1847,7 +1845,7 @@ void tscRetrieveDataRes(void *param, TAOS_RES *tres, int code) {
     return;
   }
 
-  tscTrace("%p sub:%p query complete, ep:%s, vgId:%d, orderOfSub:%d, retrieve data", trsupport->pParentSql, pSql,
+  tscDebug("%p sub:%p query complete, ep:%s, vgId:%d, orderOfSub:%d, retrieve data", trsupport->pParentSql, pSql,
              pVgroup->epAddr[0].fqdn, pVgroup->vgId, trsupport->subqueryIndex);
 
   if (pSql->res.qhandle == 0) { // qhandle is NULL, code is TSDB_CODE_SUCCESS means no results generated from this vnode
@@ -1926,8 +1924,14 @@ int32_t tscHandleMultivnodeInsert(SSqlObj *pSql) {
   size_t size = taosArrayGetSize(pCmd->pDataBlocks);
   assert(size > 0);
 
-  pSql->pSubs = calloc(size, POINTER_BYTES);
+  // the number of already initialized subqueries
+  int32_t numOfSub = 0;
+
   pSql->numOfSubs = (uint16_t)size;
+  pSql->pSubs = calloc(size, POINTER_BYTES);
+  if (pSql->pSubs == NULL) {
+    goto _error;
+  }
 
   tscDebug("%p submit data to %" PRIzu " vnode(s)", pSql, size);
 
@@ -1936,10 +1940,13 @@ int32_t tscHandleMultivnodeInsert(SSqlObj *pSql) {
   pState->numOfRemain = pSql->numOfSubs;
  
   pRes->code = TSDB_CODE_SUCCESS;
-  int32_t numOfSub = 0;
 
   while(numOfSub < pSql->numOfSubs) {
     SInsertSupporter* pSupporter = calloc(1, sizeof(SInsertSupporter));
+    if (pSupporter == NULL) {
+      goto _error;
+    }
+
     pSupporter->pSql   = pSql;
     pSupporter->pState = pState;
     pSupporter->index  = numOfSub;
@@ -1972,7 +1979,7 @@ int32_t tscHandleMultivnodeInsert(SSqlObj *pSql) {
   if (numOfSub < pSql->numOfSubs) {
     tscError("%p failed to prepare subObj structure and launch sub-insertion", pSql);
     pRes->code = TSDB_CODE_TSC_OUT_OF_MEMORY;
-    return pRes->code;  // free all allocated resource
+    goto _error;
   }
 
   pCmd->pDataBlocks = tscDestroyBlockArrayList(pCmd->pDataBlocks);
@@ -2070,46 +2077,8 @@ void tscBuildResFromSubqueries(SSqlObj *pSql) {
 
     doBuildResFromSubqueries(pSql);
     tsem_post(&pSql->rspSem);
-
     return;
-
-    // continue retrieve data from vnode
-//    if (!tscHasRemainDataInSubqueryResultSet(pSql)) {
-//      tscDebug("%p at least one subquery exhausted, free all other %d subqueries", pSql, pSql->numOfSubs - 1);
-//      SSubqueryState* pState = NULL;
-//
-//      // free all sub sqlobj
-//      for (int32_t i = 0; i < pSql->numOfSubs; ++i) {
-//        SSqlObj* pChildObj = pSql->pSubs[i];
-//        if (pChildObj == NULL) {
-//          continue;
-//        }
-//
-//        SJoinSupporter* pSupporter = (SJoinSupporter*)pChildObj->param;
-//        pState = pSupporter->pState;
-//
-//        tscDestroyJoinSupporter(pChildObj->param);
-//        taos_free_result(pChildObj);
-//      }
-//
-//      free(pState);
-//
-//      pRes->completed = true;  // set query completed
-//      tsem_post(&pSql->rspSem);
-//      return;
-//    }
-
-//    tscFetchDatablockFromSubquery(pSql);
-//    if (pRes->code != TSDB_CODE_SUCCESS) {
-//      return;
-//    }
   }
-
-//  if (pSql->res.code == TSDB_CODE_SUCCESS) {
-//    (*pSql->fp)(pSql->param, pSql, pRes->numOfRows);
-//  } else {
-//    tscQueueAsyncRes(pSql);
-//  }
 }
 
 static void transferNcharData(SSqlObj *pSql, int32_t columnIndex, TAOS_FIELD *pField) {
@@ -2159,7 +2128,6 @@ void **doSetResultRowData(SSqlObj *pSql, bool finalResult) {
   SSqlRes *pRes = &pSql->res;
 
   assert(pRes->row >= 0 && pRes->row <= pRes->numOfRows);
-
   if (pRes->row >= pRes->numOfRows) {  // all the results has returned to invoker
     taosTFree(pRes->tsrow);
     return pRes->tsrow;
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index fa148ebb2a..b61fd7e8c9 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -373,7 +373,7 @@ void tscFreeSqlObj(SSqlObj* pSql) {
   if (pSql == NULL || pSql->signature != pSql) {
     return;
   }
-  
+
   tscDebug("%p start to free sql object", pSql);
   tscPartiallyFreeSqlObj(pSql);
 
@@ -388,6 +388,7 @@ void tscFreeSqlObj(SSqlObj* pSql) {
   
   taosTFree(pSql->sqlstr);
   tsem_destroy(&pSql->rspSem);
+
   free(pSql);
 }
 
@@ -485,15 +486,6 @@ int32_t tscCopyDataBlockToPayload(SSqlObj* pSql, STableDataBlocks* pDataBlock) {
   return TSDB_CODE_SUCCESS;
 }
 
-//void tscFreeUnusedDataBlocks(SDataBlockList* pList) {
-//  /* release additional memory consumption */
-//  for (int32_t i = 0; i < pList->nSize; ++i) {
-//    STableDataBlocks* pDataBlock = pList->pData[i];
-//    pDataBlock->pData = realloc(pDataBlock->pData, pDataBlock->size);
-//    pDataBlock->nAllocSize = (uint32_t)pDataBlock->size;
-//  }
-//}
-
 /**
  * create the in-memory buffer for each table to keep the submitted data block
  * @param initialSize
@@ -518,6 +510,11 @@ int32_t tscCreateDataBlock(size_t initialSize, int32_t rowSize, int32_t startOff
   }
   
   dataBuf->pData = calloc(1, dataBuf->nAllocSize);
+  if (dataBuf->pData == NULL) {
+    tscError("failed to allocated memory, reason:%s", strerror(errno));
+    return TSDB_CODE_TSC_OUT_OF_MEMORY;
+  }
+
   dataBuf->ordered = true;
   dataBuf->prevTS = INT64_MIN;
 
@@ -742,7 +739,7 @@ bool tscIsInsertData(char* sqlstr) {
   int32_t index = 0;
 
   do {
-    SSQLToken t0 = tStrGetToken(sqlstr, &index, false, 0, NULL);
+    SStrToken t0 = tStrGetToken(sqlstr, &index, false, 0, NULL);
     if (t0.type != TK_LP) {
       return t0.type == TK_INSERT || t0.type == TK_IMPORT;
     }
@@ -926,17 +923,23 @@ void tscFieldInfoClear(SFieldInfo* pFieldInfo) {
 }
 
 static SSqlExpr* doBuildSqlExpr(SQueryInfo* pQueryInfo, int16_t functionId, SColumnIndex* pColIndex, int16_t type,
-    int16_t size, int16_t interSize, bool isTagCol) {
+    int16_t size, int16_t interSize, int32_t colType) {
   STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, pColIndex->tableIndex);
   
   SSqlExpr* pExpr = calloc(1, sizeof(SSqlExpr));
+  if (pExpr == NULL) {
+    return NULL;
+  }
+
   pExpr->functionId = functionId;
-  
+
   // set the correct columnIndex index
   if (pColIndex->columnIndex == TSDB_TBNAME_COLUMN_INDEX) {
     pExpr->colInfo.colId = TSDB_TBNAME_COLUMN_INDEX;
+  } else if (pColIndex->columnIndex <= TSDB_UD_COLUMN_INDEX) {
+    pExpr->colInfo.colId = pColIndex->columnIndex;
   } else {
-    if (isTagCol) {
+    if (TSDB_COL_IS_TAG(colType)) {
       SSchema* pSchema = tscGetTableTagSchema(pTableMetaInfo->pTableMeta);
       pExpr->colInfo.colId = pSchema[pColIndex->columnIndex].colId;
       tstrncpy(pExpr->colInfo.name, pSchema[pColIndex->columnIndex].name, sizeof(pExpr->colInfo.name));
@@ -948,9 +951,9 @@ static SSqlExpr* doBuildSqlExpr(SQueryInfo* pQueryInfo, int16_t functionId, SCol
     }
   }
   
-  pExpr->colInfo.flag = isTagCol? TSDB_COL_TAG:TSDB_COL_NORMAL;
-  
+  pExpr->colInfo.flag     = colType;
   pExpr->colInfo.colIndex = pColIndex->columnIndex;
+
   pExpr->resType       = type;
   pExpr->resBytes      = size;
   pExpr->interBytes    = interSize;
@@ -1060,8 +1063,11 @@ void tscSqlExprCopy(SArray* dst, const SArray* src, uint64_t uid, bool deepcopy)
       
       if (deepcopy) {
         SSqlExpr* p1 = calloc(1, sizeof(SSqlExpr));
+        if (p1 == NULL) {
+          assert(0);
+        }
+
         *p1 = *pExpr;
-  
         for (int32_t j = 0; j < pExpr->numOfParams; ++j) {
           tVariantAssign(&p1->param[j], &pExpr->param[j]);
         }
@@ -1097,16 +1103,22 @@ SColumn* tscColumnListInsert(SArray* pColumnList, SColumnIndex* pColIndex) {
 
   if (i >= numOfCols || numOfCols == 0) {
     SColumn* b = calloc(1, sizeof(SColumn));
+    if (b == NULL) {
+      return NULL;
+    }
+
     b->colIndex = *pColIndex;
-    
     taosArrayInsert(pColumnList, i, &b);
   } else {
     SColumn* pCol = taosArrayGetP(pColumnList, i);
   
     if (i < numOfCols && (pCol->colIndex.columnIndex > col || pCol->colIndex.tableIndex != pColIndex->tableIndex)) {
       SColumn* b = calloc(1, sizeof(SColumn));
+      if (b == NULL) {
+        return NULL;
+      }
+
       b->colIndex = *pColIndex;
-      
       taosArrayInsert(pColumnList, i, &b);
     }
   }
@@ -1128,7 +1140,10 @@ SColumn* tscColumnClone(const SColumn* src) {
   assert(src != NULL);
   
   SColumn* dst = calloc(1, sizeof(SColumn));
-  
+  if (dst == NULL) {
+    return NULL;
+  }
+
   dst->colIndex     = src->colIndex;
   dst->numOfFilters = src->numOfFilters;
   dst->filterInfo   = tscFilterInfoClone(src->filterInfo, src->numOfFilters);
@@ -1183,7 +1198,7 @@ void tscColumnListDestroy(SArray* pColumnList) {
  * 'first_part.second_part'
  *
  */
-static int32_t validateQuoteToken(SSQLToken* pToken) {
+static int32_t validateQuoteToken(SStrToken* pToken) {
   strdequote(pToken->z);
   pToken->n = (uint32_t)strtrim(pToken->z);
 
@@ -1199,7 +1214,7 @@ static int32_t validateQuoteToken(SSQLToken* pToken) {
   return TSDB_CODE_SUCCESS;
 }
 
-int32_t tscValidateName(SSQLToken* pToken) {
+int32_t tscValidateName(SStrToken* pToken) {
   if (pToken->type != TK_STRING && pToken->type != TK_ID) {
     return TSDB_CODE_TSC_INVALID_SQL;
   }
@@ -1286,12 +1301,12 @@ void tscIncStreamExecutionCount(void* pStream) {
   ps->num += 1;
 }
 
-bool tscValidateColumnId(STableMetaInfo* pTableMetaInfo, int32_t colId) {
+bool tscValidateColumnId(STableMetaInfo* pTableMetaInfo, int32_t colId, int32_t numOfParams) {
   if (pTableMetaInfo->pTableMeta == NULL) {
     return false;
   }
 
-  if (colId == TSDB_TBNAME_COLUMN_INDEX) {
+  if (colId == TSDB_TBNAME_COLUMN_INDEX || (colId <= TSDB_UD_COLUMN_INDEX && numOfParams == 2)) {
     return true;
   }
 
@@ -1338,6 +1353,10 @@ void tscTagCondCopy(STagCond* dest, const STagCond* src) {
     if (pCond->len > 0) {
       assert(pCond->cond != NULL);
       c.cond = malloc(c.len);
+      if (c.cond == NULL) {
+        assert(0);
+      }
+
       memcpy(c.cond, pCond->cond, c.len);
     }
     
@@ -1463,20 +1482,20 @@ STableMetaInfo* tscGetMetaInfo(SQueryInfo* pQueryInfo, int32_t tableIndex) {
   return pQueryInfo->pTableMetaInfo[tableIndex];
 }
 
-int32_t tscGetQueryInfoDetailSafely(SSqlCmd* pCmd, int32_t subClauseIndex, SQueryInfo** pQueryInfo) {
+SQueryInfo* tscGetQueryInfoDetailSafely(SSqlCmd* pCmd, int32_t subClauseIndex) {
+  SQueryInfo* pQueryInfo = tscGetQueryInfoDetail(pCmd, subClauseIndex);
   int32_t ret = TSDB_CODE_SUCCESS;
 
-  *pQueryInfo = tscGetQueryInfoDetail(pCmd, subClauseIndex);
-
-  while ((*pQueryInfo) == NULL) {
+  while ((pQueryInfo) == NULL) {
     if ((ret = tscAddSubqueryInfo(pCmd)) != TSDB_CODE_SUCCESS) {
-      return ret;
+      terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
+      return NULL;
     }
 
-    (*pQueryInfo) = tscGetQueryInfoDetail(pCmd, subClauseIndex);
+    pQueryInfo = tscGetQueryInfoDetail(pCmd, subClauseIndex);
   }
 
-  return TSDB_CODE_SUCCESS;
+  return pQueryInfo;
 }
 
 STableMetaInfo* tscGetTableMetaInfoByUid(SQueryInfo* pQueryInfo, uint64_t uid, int32_t* index) {
@@ -1507,6 +1526,7 @@ void tscInitQueryInfo(SQueryInfo* pQueryInfo) {
   assert(pQueryInfo->exprList == NULL);
   pQueryInfo->exprList = taosArrayInit(4, POINTER_BYTES);
   pQueryInfo->colList  = taosArrayInit(4, POINTER_BYTES);
+  pQueryInfo->udColumnId = TSDB_UD_COLUMN_INDEX;
 }
 
 int32_t tscAddSubqueryInfo(SSqlCmd* pCmd) {
@@ -1522,8 +1542,11 @@ int32_t tscAddSubqueryInfo(SSqlCmd* pCmd) {
   pCmd->pQueryInfo = (SQueryInfo**)tmp;
 
   SQueryInfo* pQueryInfo = calloc(1, sizeof(SQueryInfo));
+  if (pQueryInfo == NULL) {
+    return TSDB_CODE_TSC_OUT_OF_MEMORY;
+  }
+
   tscInitQueryInfo(pQueryInfo);
-  
   pQueryInfo->msg = pCmd->payload;  // pointer to the parent error message buffer
 
   pCmd->pQueryInfo[pCmd->numOfClause++] = pQueryInfo;
@@ -1584,14 +1607,18 @@ STableMetaInfo* tscAddTableMetaInfo(SQueryInfo* pQueryInfo, const char* name, ST
                                     SVgroupsInfo* vgroupList, SArray* pTagCols) {
   void* pAlloc = realloc(pQueryInfo->pTableMetaInfo, (pQueryInfo->numOfTables + 1) * POINTER_BYTES);
   if (pAlloc == NULL) {
+    terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
     return NULL;
   }
 
   pQueryInfo->pTableMetaInfo = pAlloc;
-  pQueryInfo->pTableMetaInfo[pQueryInfo->numOfTables] = calloc(1, sizeof(STableMetaInfo));
+  STableMetaInfo* pTableMetaInfo = calloc(1, sizeof(STableMetaInfo));
+  if (pTableMetaInfo == NULL) {
+    terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
+    return NULL;
+  }
 
-  STableMetaInfo* pTableMetaInfo = pQueryInfo->pTableMetaInfo[pQueryInfo->numOfTables];
-  assert(pTableMetaInfo != NULL);
+  pQueryInfo->pTableMetaInfo[pQueryInfo->numOfTables] = pTableMetaInfo;
 
   if (name != NULL) {
     tstrncpy(pTableMetaInfo->name, name, sizeof(pTableMetaInfo->name));
@@ -1602,10 +1629,18 @@ STableMetaInfo* tscAddTableMetaInfo(SQueryInfo* pQueryInfo, const char* name, ST
   if (vgroupList != NULL) {
     size_t size = sizeof(SVgroupsInfo) + sizeof(SCMVgroupInfo) * vgroupList->numOfVgroups;
     pTableMetaInfo->vgroupList = malloc(size);
+    if (pTableMetaInfo->vgroupList == NULL) {
+      return NULL;
+    }
+
     memcpy(pTableMetaInfo->vgroupList, vgroupList, size);
   }
 
   pTableMetaInfo->tagColList = taosArrayInit(4, POINTER_BYTES);
+  if (pTableMetaInfo->tagColList == NULL) {
+    return NULL;
+  }
+
   if (pTagCols != NULL) {
     tscColumnListCopy(pTableMetaInfo->tagColList, pTagCols, -1);
   }
@@ -1671,8 +1706,7 @@ SSqlObj* createSimpleSubObj(SSqlObj* pSql, void (*fp)(), void* param, int32_t cm
     return NULL;
   }
 
-  SQueryInfo* pQueryInfo = NULL;
-  tscGetQueryInfoDetailSafely(pCmd, 0, &pQueryInfo);
+  SQueryInfo* pQueryInfo = tscGetQueryInfoDetailSafely(pCmd, 0);
 
   assert(pSql->cmd.clauseIndex == 0);
   STableMetaInfo* pMasterTableMetaInfo = tscGetTableMetaInfoFromCmd(&pSql->cmd, pSql->cmd.clauseIndex, 0);
@@ -1754,6 +1788,7 @@ static void doSetSqlExprAndResultFieldInfo(SQueryInfo* pQueryInfo, SQueryInfo* p
 
 SSqlObj* createSubqueryObj(SSqlObj* pSql, int16_t tableIndex, void (*fp)(), void* param, int32_t cmd, SSqlObj* pPrevSql) {
   SSqlCmd* pCmd = &pSql->cmd;
+
   SSqlObj* pNew = (SSqlObj*)calloc(1, sizeof(SSqlObj));
   if (pNew == NULL) {
     tscError("%p new subquery failed, tableIndex:%d", pSql, tableIndex);
@@ -1769,10 +1804,8 @@ SSqlObj* createSubqueryObj(SSqlObj* pSql, int16_t tableIndex, void (*fp)(), void
   pNew->sqlstr = strdup(pSql->sqlstr);
   if (pNew->sqlstr == NULL) {
     tscError("%p new subquery failed, tableIndex:%d, vgroupIndex:%d", pSql, tableIndex, pTableMetaInfo->vgroupIndex);
-
-    free(pNew);
     terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
-    return NULL;
+    goto _error;
   }
 
   SSqlCmd* pnCmd = &pNew->cmd;
@@ -1789,9 +1822,8 @@ SSqlObj* createSubqueryObj(SSqlObj* pSql, int16_t tableIndex, void (*fp)(), void
   pnCmd->parseFinished = 1;
 
   if (tscAddSubqueryInfo(pnCmd) != TSDB_CODE_SUCCESS) {
-    tscFreeSqlObj(pNew);
     terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
-    return NULL;
+    goto _error;
   }
 
   SQueryInfo* pNewQueryInfo = tscGetQueryInfoDetail(pnCmd, 0);
@@ -1816,20 +1848,28 @@ SSqlObj* createSubqueryObj(SSqlObj* pSql, int16_t tableIndex, void (*fp)(), void
   pNewQueryInfo->groupbyExpr = pQueryInfo->groupbyExpr;
   if (pQueryInfo->groupbyExpr.columnInfo != NULL) {
     pNewQueryInfo->groupbyExpr.columnInfo = taosArrayClone(pQueryInfo->groupbyExpr.columnInfo);
+    if (pNewQueryInfo->groupbyExpr.columnInfo == NULL) {
+      terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
+      goto _error;
+    }
   }
   
   tscTagCondCopy(&pNewQueryInfo->tagCond, &pQueryInfo->tagCond);
 
   if (pQueryInfo->fillType != TSDB_FILL_NONE) {
     pNewQueryInfo->fillVal = malloc(pQueryInfo->fieldsInfo.numOfOutput * sizeof(int64_t));
+    if (pNewQueryInfo->fillVal == NULL) {
+      terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
+      goto _error;
+    }
+
     memcpy(pNewQueryInfo->fillVal, pQueryInfo->fillVal, pQueryInfo->fieldsInfo.numOfOutput * sizeof(int64_t));
   }
 
   if (tscAllocPayload(pnCmd, TSDB_DEFAULT_PAYLOAD_SIZE) != TSDB_CODE_SUCCESS) {
     tscError("%p new subquery failed, tableIndex:%d, vgroupIndex:%d", pSql, tableIndex, pTableMetaInfo->vgroupIndex);
-    tscFreeSqlObj(pNew);
     terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
-    return NULL;
+    goto _error;
   }
   
   tscColumnListCopy(pNewQueryInfo->colList, pQueryInfo->colList, (int16_t)tableIndex);
@@ -1872,16 +1912,15 @@ SSqlObj* createSubqueryObj(SSqlObj* pSql, int16_t tableIndex, void (*fp)(), void
 
   if (pFinalInfo->pTableMeta == NULL) {
     tscError("%p new subquery failed since no tableMeta in cache, name:%s", pSql, name);
-    tscFreeSqlObj(pNew);
 
-    if (pPrevSql != NULL) {
+    if (pPrevSql != NULL) { // pass the previous error to client
       assert(pPrevSql->res.code != TSDB_CODE_SUCCESS);
       terrno = pPrevSql->res.code;
     } else {
       terrno = TSDB_CODE_TSC_APP_ERROR;
     }
 
-    return NULL;
+    goto _error;
   }
   
   assert(pNewQueryInfo->numOfTables == 1);
@@ -1906,6 +1945,10 @@ SSqlObj* createSubqueryObj(SSqlObj* pSql, int16_t tableIndex, void (*fp)(), void
   }
 
   return pNew;
+
+_error:
+  tscFreeSqlObj(pNew);
+  return NULL;
 }
 
 /**
diff --git a/src/common/inc/tname.h b/src/common/inc/tname.h
index 2263a5dae1..2a4ac3fc40 100644
--- a/src/common/inc/tname.h
+++ b/src/common/inc/tname.h
@@ -4,6 +4,7 @@
 #include "os.h"
 #include "taosmsg.h"
 #include "tstoken.h"
+#include "tvariant.h"
 
 typedef struct SDataStatis {
   int16_t colId;
@@ -24,10 +25,12 @@ void extractTableName(const char *tableId, char *name);
 
 char* extractDBName(const char *tableId, char *name);
 
-void extractTableNameFromToken(SSQLToken *pToken, SSQLToken* pTable);
+void extractTableNameFromToken(SStrToken *pToken, SStrToken* pTable);
 
 SSchema tGetTableNameColumnSchema();
 
+SSchema tGetUserSpecifiedColumnSchema(tVariant* pVal, SStrToken* exprStr, const char* name);
+
 bool tscValidateTableNameLength(size_t len);
 
 SColumnFilterInfo* tscFilterInfoClone(const SColumnFilterInfo* src, int32_t numOfFilters);
diff --git a/src/common/inc/tvariant.h b/src/common/inc/tvariant.h
index 4fd6ea5541..e9973bcb95 100644
--- a/src/common/inc/tvariant.h
+++ b/src/common/inc/tvariant.h
@@ -36,7 +36,7 @@ typedef struct tVariant {
   };
 } tVariant;
 
-void tVariantCreate(tVariant *pVar, SSQLToken *token);
+void tVariantCreate(tVariant *pVar, SStrToken *token);
 
 void tVariantCreateFromString(tVariant *pVar, char *pz, uint32_t len, uint32_t type);
 
@@ -46,6 +46,8 @@ void tVariantDestroy(tVariant *pV);
 
 void tVariantAssign(tVariant *pDst, const tVariant *pSrc);
 
+int32_t tVariantCompare(const tVariant* p1, const tVariant* p2);
+
 int32_t tVariantToString(tVariant *pVar, char *dst);
 
 int32_t tVariantDump(tVariant *pVariant, char *payload, int16_t type, bool includeLengthPrefix);
diff --git a/src/common/src/tname.c b/src/common/src/tname.c
index d80ddb0ee2..01945dbb00 100644
--- a/src/common/src/tname.c
+++ b/src/common/src/tname.c
@@ -4,6 +4,7 @@
 #include "tname.h"
 #include "tstoken.h"
 #include "ttokendef.h"
+#include "tvariant.h"
 
 // todo refactor
 UNUSED_FUNC static FORCE_INLINE const char* skipSegments(const char* input, char delim, int32_t num) {
@@ -43,7 +44,30 @@ SSchema tGetTableNameColumnSchema() {
   s.bytes = TSDB_TABLE_NAME_LEN - 1 + VARSTR_HEADER_SIZE;
   s.type  = TSDB_DATA_TYPE_BINARY;
   s.colId = TSDB_TBNAME_COLUMN_INDEX;
-  strncpy(s.name, TSQL_TBNAME_L, TSDB_COL_NAME_LEN);
+  tstrncpy(s.name, TSQL_TBNAME_L, TSDB_COL_NAME_LEN);
+  return s;
+}
+
+SSchema tGetUserSpecifiedColumnSchema(tVariant* pVal, SStrToken* exprStr, const char* name) {
+  SSchema s = {0};
+
+  s.type  = pVal->nType;
+  if (s.type == TSDB_DATA_TYPE_BINARY || s.type == TSDB_DATA_TYPE_NCHAR) {
+    s.bytes = (int16_t)(pVal->nLen + VARSTR_HEADER_SIZE);
+  } else {
+    s.bytes = tDataTypeDesc[pVal->nType].nSize;
+  }
+
+  s.colId = TSDB_UD_COLUMN_INDEX;
+  if (name != NULL) {
+    tstrncpy(s.name, name, sizeof(s.name));
+  } else {
+    size_t len = strdequote(exprStr->z);
+    size_t tlen = MIN(sizeof(s.name), len + 1);
+
+    tstrncpy(s.name, exprStr->z, tlen);
+  }
+
   return s;
 }
 
@@ -110,7 +134,7 @@ int64_t taosGetIntervalStartTimestamp(int64_t startTime, int64_t slidingTime, in
  * tablePrefix.columnName
  * extract table name and save it in pTable, with only column name in pToken
  */
-void extractTableNameFromToken(SSQLToken* pToken, SSQLToken* pTable) {
+void extractTableNameFromToken(SStrToken* pToken, SStrToken* pTable) {
   const char sep = TS_PATH_DELIMITER[0];
 
   if (pToken == pTable || pToken == NULL || pTable == NULL) {
diff --git a/src/common/src/tvariant.c b/src/common/src/tvariant.c
index 5460d21252..069d8eb251 100644
--- a/src/common/src/tvariant.c
+++ b/src/common/src/tvariant.c
@@ -12,12 +12,10 @@
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
+#include "os.h"
 
 #include "tvariant.h"
 #include "hash.h"
-#include "hashfunc.h"
-#include "os.h"
-#include "hash.h"
 #include "taos.h"
 #include "taosdef.h"
 #include "tstoken.h"
@@ -25,7 +23,7 @@
 #include "tutil.h"
 
 // todo support scientific expression number and oct number
-void tVariantCreate(tVariant *pVar, SSQLToken *token) { tVariantCreateFromString(pVar, token->z, token->n, token->type); }
+void tVariantCreate(tVariant *pVar, SStrToken *token) { tVariantCreateFromString(pVar, token->z, token->n, token->type); }
 
 void tVariantCreateFromString(tVariant *pVar, char *pz, uint32_t len, uint32_t type) {
   memset(pVar, 0, sizeof(tVariant));
@@ -102,10 +100,9 @@ void tVariantCreateFromBinary(tVariant *pVar, const char *pz, size_t len, uint32
     }
     case TSDB_DATA_TYPE_NCHAR: { // here we get the nchar length from raw binary bits length
       size_t lenInwchar = len / TSDB_NCHAR_SIZE;
+
       pVar->wpz = calloc(1, (lenInwchar + 1) * TSDB_NCHAR_SIZE);
-      
-      wcsncpy(pVar->wpz, (wchar_t *)pz, lenInwchar);
-      pVar->wpz[lenInwchar] = 0;
+      memcpy(pVar->wpz, pz, lenInwchar * TSDB_NCHAR_SIZE);
       pVar->nLen = (int32_t)len;
       
       break;
@@ -169,6 +166,50 @@ void tVariantAssign(tVariant *pDst, const tVariant *pSrc) {
       char* n = strdup(p);
       taosArrayPush(pDst->arr, &n);
     }
+
+    return;
+  }
+
+  pDst->nLen = tDataTypeDesc[pDst->nType].nSize;
+}
+
+int32_t tVariantCompare(const tVariant* p1, const tVariant* p2) {
+  if (p1->nType == TSDB_DATA_TYPE_NULL && p2->nType == TSDB_DATA_TYPE_NULL) {
+    return 0;
+  }
+
+  if (p1->nType == TSDB_DATA_TYPE_NULL) {
+    return -1;
+  }
+
+  if (p2->nType == TSDB_DATA_TYPE_NULL) {
+    return 1;
+  }
+
+  switch (p1->nType) {
+    case TSDB_DATA_TYPE_BINARY:
+    case TSDB_DATA_TYPE_NCHAR: {
+      if (p1->nLen == p2->nLen) {
+        return memcmp(p1->pz, p2->pz, p1->nLen);
+      } else {
+        return p1->nLen > p2->nLen? 1:-1;
+      }
+    };
+
+    case TSDB_DATA_TYPE_FLOAT:
+    case TSDB_DATA_TYPE_DOUBLE:
+      if (p1->dKey == p2->dKey) {
+        return 0;
+      } else {
+        return p1->dKey > p2->dKey? 1:-1;
+      }
+
+    default:
+      if (p1->i64Key == p2->i64Key) {
+        return 0;
+      } else {
+        return p1->i64Key > p2->i64Key? 1:-1;
+      }
   }
 }
 
@@ -228,7 +269,7 @@ static int32_t doConvertToInteger(tVariant *pVariant, char *pDest, int32_t type,
     errno = 0;
     char *endPtr = NULL;
 
-    SSQLToken token = {0};
+    SStrToken token = {0};
     token.n = tSQLGetToken(pVariant->pz, &token.type);
 
     if (token.type == TK_MINUS || token.type == TK_PLUS) {
@@ -277,7 +318,7 @@ static int32_t doConvertToInteger(tVariant *pVariant, char *pDest, int32_t type,
     errno = 0;
     wchar_t *endPtr = NULL;
 
-    SSQLToken token = {0};
+    SStrToken token = {0};
     token.n = tSQLGetToken(pVariant->pz, &token.type);
 
     if (token.type == TK_MINUS || token.type == TK_PLUS) {
@@ -436,7 +477,7 @@ static int32_t toNchar(tVariant *pVariant, char **pDest, int32_t *pDestSize) {
 }
 
 static FORCE_INLINE int32_t convertToDouble(char *pStr, int32_t len, double *value) {
-  SSQLToken stoken = {.z = pStr, .n = len};
+  SStrToken stoken = {.z = pStr, .n = len};
   
   if (TK_ILLEGAL == isValidNumber(&stoken)) {
     return -1;
@@ -462,7 +503,7 @@ static FORCE_INLINE int32_t convertToInteger(tVariant *pVariant, int64_t *result
     errno = 0;
     char *endPtr = NULL;
     
-    SSQLToken token = {0};
+    SStrToken token = {0};
     token.n = tSQLGetToken(pVariant->pz, &token.type);
     
     if (token.type == TK_MINUS || token.type == TK_PLUS) {
@@ -479,7 +520,7 @@ static FORCE_INLINE int32_t convertToInteger(tVariant *pVariant, int64_t *result
       return 0;
     }
     
-    SSQLToken sToken = {.z = pVariant->pz, .n = pVariant->nLen};
+    SStrToken sToken = {.z = pVariant->pz, .n = pVariant->nLen};
     if (TK_ILLEGAL == isValidNumber(&sToken)) {
       return -1;
     }
@@ -515,7 +556,7 @@ static FORCE_INLINE int32_t convertToInteger(tVariant *pVariant, int64_t *result
     errno = 0;
     wchar_t *endPtr = NULL;
     
-    SSQLToken token = {0};
+    SStrToken token = {0};
     token.n = tSQLGetToken(pVariant->pz, &token.type);
     
     if (token.type == TK_MINUS || token.type == TK_PLUS) {
diff --git a/src/connector/jdbc/.classpath b/src/connector/jdbc/.classpath
index 39abf1c5e9..a5d95095cc 100644
--- a/src/connector/jdbc/.classpath
+++ b/src/connector/jdbc/.classpath
@@ -28,22 +28,5 @@
 			<attribute name="maven.pomderived" value="true"/>
 		</attributes>
 	</classpathentry>
-	<classpathentry kind="src" path="target/generated-sources/annotations">
-		<attributes>
-			<attribute name="optional" value="true"/>
-			<attribute name="maven.pomderived" value="true"/>
-			<attribute name="ignore_optional_problems" value="true"/>
-			<attribute name="m2e-apt" value="true"/>
-		</attributes>
-	</classpathentry>
-	<classpathentry kind="src" output="target/test-classes" path="target/generated-test-sources/test-annotations">
-		<attributes>
-			<attribute name="optional" value="true"/>
-			<attribute name="maven.pomderived" value="true"/>
-			<attribute name="ignore_optional_problems" value="true"/>
-			<attribute name="m2e-apt" value="true"/>
-			<attribute name="test" value="true"/>
-		</attributes>
-	</classpathentry>
 	<classpathentry kind="output" path="target/classes"/>
 </classpath>
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBStatement.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBStatement.java
index a36f7c67a0..06ae449596 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBStatement.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBStatement.java
@@ -52,7 +52,7 @@ public class TSDBStatement implements Statement {
         if (isClosed) {
             throw new SQLException("Invalid method call on a closed statement.");
         }
-        
+
         // TODO make sure it is not a update query
 		pSql = this.connecter.executeQuery(sql);
 
@@ -68,21 +68,21 @@ public class TSDBStatement implements Statement {
 			this.connecter.freeResultSet(pSql);
 			return null;
 		}
-		
+
 		if (!this.connecter.isUpdateQuery(pSql)) {
 			return new TSDBResultSet(this.connecter, resultSetPointer);
 		} else {
 			this.connecter.freeResultSet(pSql);
 			return null;
 		}
-		
+
 	}
 
 	public int executeUpdate(String sql) throws SQLException {
         if (isClosed) {
             throw new SQLException("Invalid method call on a closed statement.");
         }
-        
+
         // TODO check if current query is update query
 		pSql = this.connecter.executeQuery(sql);
 		long resultSetPointer = this.connecter.getResultSet();
@@ -94,7 +94,7 @@ public class TSDBStatement implements Statement {
 
 		this.affectedRows = this.connecter.getAffectedRows(pSql);
 		this.connecter.freeResultSet(pSql);
-		
+
 		return this.affectedRows;
 	}
 
@@ -192,7 +192,7 @@ public class TSDBStatement implements Statement {
         if (isClosed) {
             throw new SQLException("Invalid method call on a closed statement.");
         }
-        
+
 		return this.affectedRows;
 	}
 
diff --git a/src/dnode/src/dnodeSystem.c b/src/dnode/src/dnodeSystem.c
index 6f32bc0f7a..56316e9619 100644
--- a/src/dnode/src/dnodeSystem.c
+++ b/src/dnode/src/dnodeSystem.c
@@ -119,11 +119,8 @@ int32_t main(int32_t argc, char *argv[]) {
 
   syslog(LOG_INFO, "Started TDengine service successfully.");
 
-  for (int res = tsem_wait(&exitSem); res != 0; res = tsem_wait(&exitSem)) {
-    if (res != EINTR) {
-      syslog(LOG_ERR, "failed to wait exit semphore: %d", res);
-      break;
-    }
+  if (tsem_wait(&exitSem) != 0) {
+    syslog(LOG_ERR, "failed to wait exit semphore: %s", strerror(errno));
   }
 
   dnodeCleanUpSystem();
diff --git a/src/inc/taosdef.h b/src/inc/taosdef.h
index b6d185db9c..b61890347f 100644
--- a/src/inc/taosdef.h
+++ b/src/inc/taosdef.h
@@ -286,7 +286,8 @@ void tsDataSwap(void *pLeft, void *pRight, int32_t type, int32_t size);
 
 #define TSDB_MAX_REPLICA          5
 
-#define TSDB_TBNAME_COLUMN_INDEX       (-1)
+#define TSDB_TBNAME_COLUMN_INDEX        (-1)
+#define TSDB_UD_COLUMN_INDEX            (-100)
 #define TSDB_MULTI_METERMETA_MAX_NUM    100000  // maximum batch size allowed to load metermeta
 
 #define TSDB_MIN_CACHE_BLOCK_SIZE       1
diff --git a/src/inc/taoserror.h b/src/inc/taoserror.h
index df69d1d19a..a789d002bf 100644
--- a/src/inc/taoserror.h
+++ b/src/inc/taoserror.h
@@ -97,6 +97,7 @@ TAOS_DEFINE_ERROR(TSDB_CODE_TSC_APP_ERROR,                0, 0x0211, "Applicatio
 TAOS_DEFINE_ERROR(TSDB_CODE_TSC_ACTION_IN_PROGRESS,       0, 0x0212, "Action in progress")
 TAOS_DEFINE_ERROR(TSDB_CODE_TSC_DISCONNECTED,             0, 0x0213, "Disconnected from service")
 TAOS_DEFINE_ERROR(TSDB_CODE_TSC_NO_WRITE_AUTH,            0, 0x0214, "No write permission")
+TAOS_DEFINE_ERROR(TSDB_CODE_TSC_CONN_KILLED,            0, 0x0215, "Connection killed")
 
 // mnode
 TAOS_DEFINE_ERROR(TSDB_CODE_MND_MSG_NOT_PROCESSED,        0, 0x0300, "Message not processed")
@@ -221,6 +222,7 @@ TAOS_DEFINE_ERROR(TSDB_CODE_QRY_EXCEED_TAGS_LIMIT,        0, 0x0706, "Tag condit
 TAOS_DEFINE_ERROR(TSDB_CODE_QRY_NOT_READY,                0, 0x0707, "Query not ready")
 TAOS_DEFINE_ERROR(TSDB_CODE_QRY_HAS_RSP,                  0, 0x0708, "Query should response")
 TAOS_DEFINE_ERROR(TSDB_CODE_QRY_IN_EXEC,                  0, 0x0709, "Multiple retrieval of this query")
+TAOS_DEFINE_ERROR(TSDB_CODE_QRY_TOO_MANY_TIMEWINDOW,      0, 0x070A, "Too many time window in query")
 
 // grant
 TAOS_DEFINE_ERROR(TSDB_CODE_GRANT_EXPIRED,                0, 0x0800, "License expired")
diff --git a/src/inc/taosmsg.h b/src/inc/taosmsg.h
index 5e7da9bbdc..761a267ce5 100644
--- a/src/inc/taosmsg.h
+++ b/src/inc/taosmsg.h
@@ -133,7 +133,7 @@ enum _mgmt_table {
   TSDB_MGMT_TABLE_MODULE,
   TSDB_MGMT_TABLE_QUERIES,
   TSDB_MGMT_TABLE_STREAMS,
-  TSDB_MGMT_TABLE_CONFIGS,
+  TSDB_MGMT_TABLE_VARIABLES,
   TSDB_MGMT_TABLE_CONNS,
   TSDB_MGMT_TABLE_SCORES,
   TSDB_MGMT_TABLE_GRANTS,
@@ -167,9 +167,9 @@ enum _mgmt_table {
 #define TSDB_VN_WRITE_ACCCESS ((char)0x2)
 #define TSDB_VN_ALL_ACCCESS (TSDB_VN_READ_ACCCESS | TSDB_VN_WRITE_ACCCESS)
 
-#define TSDB_COL_NORMAL 0x0u
-#define TSDB_COL_TAG    0x1u
-#define TSDB_COL_JOIN   0x2u
+#define TSDB_COL_NORMAL          0x0u    // the normal column of the table
+#define TSDB_COL_TAG             0x1u    // the tag column type
+#define TSDB_COL_UDC             0x2u    // the user specified normal string column, it is a dummy column
 
 extern char *taosMsg[];
 
diff --git a/src/inc/ttokendef.h b/src/inc/ttokendef.h
index e77f5741d3..c1579fe9e7 100644
--- a/src/inc/ttokendef.h
+++ b/src/inc/ttokendef.h
@@ -69,7 +69,7 @@
 #define TK_QUERIES                         51
 #define TK_CONNECTIONS                     52
 #define TK_STREAMS                         53
-#define TK_CONFIGS                         54
+#define TK_VARIABLES                       54
 #define TK_SCORES                          55
 #define TK_GRANTS                          56
 #define TK_VNODES                          57
diff --git a/src/kit/shell/src/shellEngine.c b/src/kit/shell/src/shellEngine.c
index d82ddf8871..8f7f4d9324 100644
--- a/src/kit/shell/src/shellEngine.c
+++ b/src/kit/shell/src/shellEngine.c
@@ -25,6 +25,8 @@
 #include "taosdef.h"
 #include "taoserror.h"
 #include "tglobal.h"
+#include "tsclient.h"
+
 #include <regex.h>
 
 /**************** Global variables ****************/
@@ -64,11 +66,6 @@ TAOS *shellInit(SShellArguments *args) {
   }
 
   taos_init();
-  /*
-   * set tsTableMetaKeepTimer = 3000ms
-   * means not save cache in shell
-   */
-  tsTableMetaKeepTimer = 3000;
 
   // Connect to the database.
   TAOS *con = NULL;
@@ -287,7 +284,7 @@ void shellRunCommandOnServer(TAOS *con, char command[]) {
   st = taosGetTimestampUs();
 
   TAOS_RES* pSql = taos_query(con, command);
-  result = pSql;  // set it into the global variable
+  atomic_store_ptr(&result, pSql);  // set the global TAOS_RES pointer
 
   if (taos_errno(pSql)) {
     taos_error(pSql);
@@ -298,17 +295,16 @@ void shellRunCommandOnServer(TAOS *con, char command[]) {
     fprintf(stdout, "Database changed.\n\n");
     fflush(stdout);
 
-    result = NULL;
+    atomic_store_ptr(&result, 0);
     taos_free_result(pSql);
     return;
   }
 
-  int num_fields = taos_field_count(pSql);
-  if (num_fields != 0) {  // select and show kinds of commands
+  if (!tscIsUpdateQuery(pSql)) {  // select and show kinds of commands
     int error_no = 0;
     int numOfRows = shellDumpResult(pSql, fname, &error_no, printMode);
     if (numOfRows < 0) {
-      result = NULL;
+      atomic_store_ptr(&result, 0);
       taos_free_result(pSql);
       return;
     }
@@ -331,7 +327,7 @@ void shellRunCommandOnServer(TAOS *con, char command[]) {
     wordfree(&full_path);
   }
 
-  result = NULL;
+  atomic_store_ptr(&result, 0);
   taos_free_result(pSql);
 }
 
@@ -497,7 +493,6 @@ static int dumpResultToFile(const char* fname, TAOS_RES* tres) {
   } while( row != NULL);
 
   result = NULL;
-  //taos_free_result(tres);
   fclose(fp);
 
   return numOfRows;
@@ -802,8 +797,8 @@ void write_history() {
 }
 
 void taos_error(TAOS_RES *tres) {
+  atomic_store_ptr(&result, 0);
   fprintf(stderr, "\nDB error: %s\n", taos_errstr(tres));
-  result = NULL;
   taos_free_result(tres);
 }
 
diff --git a/src/kit/shell/src/shellMain.c b/src/kit/shell/src/shellMain.c
index 8481f498dd..44de6641f6 100644
--- a/src/kit/shell/src/shellMain.c
+++ b/src/kit/shell/src/shellMain.c
@@ -18,11 +18,10 @@
 
 pthread_t pid;
 
-// TODO: IMPLEMENT INTERRUPT HANDLER.
-void interruptHandler(int signum) {
+void shellQueryInterruptHandler(int signum) {
 #ifdef LINUX
-  taos_stop_query(result);
-  result = NULL;
+  void* pResHandle = atomic_val_compare_exchange_64(&result, result, 0);
+  taos_stop_query(pResHandle);
 #else
   printf("\nReceive ctrl+c or other signal, quit shell.\n");
   exit(0);
@@ -86,7 +85,7 @@ int main(int argc, char* argv[]) {
   struct sigaction act;
   memset(&act, 0, sizeof(struct sigaction));
   
-  act.sa_handler = interruptHandler;
+  act.sa_handler = shellQueryInterruptHandler;
   sigaction(SIGTERM, &act, NULL);
   sigaction(SIGINT, &act, NULL);
 
diff --git a/src/mnode/src/mnodeDnode.c b/src/mnode/src/mnodeDnode.c
index ccb85c3301..d5b9d18e37 100644
--- a/src/mnode/src/mnodeDnode.c
+++ b/src/mnode/src/mnodeDnode.c
@@ -49,7 +49,7 @@ static int32_t mnodeProcessCreateDnodeMsg(SMnodeMsg *pMsg);
 static int32_t mnodeProcessDropDnodeMsg(SMnodeMsg *pMsg);
 static int32_t mnodeProcessCfgDnodeMsg(SMnodeMsg *pMsg);
 static void    mnodeProcessCfgDnodeMsgRsp(SRpcMsg *rpcMsg) ;
-static int32_t mnodeProcessDnodeStatusMsg(SMnodeMsg *rpcMsg);
+static int32_t mnodeProcessDnodeStatusMsg(SMnodeMsg *pMsg);
 static int32_t mnodeGetModuleMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *pConn);
 static int32_t mnodeRetrieveModules(SShowObj *pShow, char *data, int32_t rows, void *pConn);
 static int32_t mnodeGetConfigMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *pConn);
@@ -161,8 +161,8 @@ int32_t mnodeInitDnodes() {
   mnodeAddPeerMsgHandle(TSDB_MSG_TYPE_DM_STATUS, mnodeProcessDnodeStatusMsg);
   mnodeAddShowMetaHandle(TSDB_MGMT_TABLE_MODULE, mnodeGetModuleMeta);
   mnodeAddShowRetrieveHandle(TSDB_MGMT_TABLE_MODULE, mnodeRetrieveModules);
-  mnodeAddShowMetaHandle(TSDB_MGMT_TABLE_CONFIGS, mnodeGetConfigMeta);
-  mnodeAddShowRetrieveHandle(TSDB_MGMT_TABLE_CONFIGS, mnodeRetrieveConfigs);
+  mnodeAddShowMetaHandle(TSDB_MGMT_TABLE_VARIABLES, mnodeGetConfigMeta);
+  mnodeAddShowRetrieveHandle(TSDB_MGMT_TABLE_VARIABLES, mnodeRetrieveConfigs);
   mnodeAddShowMetaHandle(TSDB_MGMT_TABLE_VNODES, mnodeGetVnodeMeta);
   mnodeAddShowRetrieveHandle(TSDB_MGMT_TABLE_VNODES, mnodeRetrieveVnodes);
   mnodeAddShowMetaHandle(TSDB_MGMT_TABLE_DNODE, mnodeGetDnodeMeta);
@@ -733,7 +733,7 @@ static int32_t mnodeRetrieveDnodes(SShowObj *pShow, char *data, int32_t rows, vo
 }
 
 static bool mnodeCheckModuleInDnode(SDnodeObj *pDnode, int32_t moduleType) {
-  uint32_t status = pDnode->moduleStatus & (1 << moduleType);
+  uint32_t status = pDnode->moduleStatus & (1u << moduleType);
   return status > 0;
 }
 
@@ -758,7 +758,7 @@ static int32_t mnodeGetModuleMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *p
 
   pShow->bytes[cols] = 40 + VARSTR_HEADER_SIZE;
   pSchema[cols].type = TSDB_DATA_TYPE_BINARY;
-  strcpy(pSchema[cols].name, "end point");
+  strcpy(pSchema[cols].name, "end_point");
   pSchema[cols].bytes = htons(pShow->bytes[cols]);
   cols++;
 
@@ -792,7 +792,9 @@ static int32_t mnodeGetModuleMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *p
 
 int32_t mnodeRetrieveModules(SShowObj *pShow, char *data, int32_t rows, void *pConn) {
   int32_t numOfRows = 0;
-  char *  pWrite;
+
+  char* pWrite;
+  char* moduleName[5] = { "MNODE", "HTTP", "MONITOR", "MQTT", "UNKNOWN" };
 
   while (numOfRows < rows) {
     SDnodeObj *pDnode = NULL;
@@ -807,28 +809,18 @@ int32_t mnodeRetrieveModules(SShowObj *pShow, char *data, int32_t rows, void *pC
       cols++;
 
       pWrite = data + pShow->offset[cols] * rows + pShow->bytes[cols] * numOfRows;
-      strncpy(pWrite, pDnode->dnodeEp, pShow->bytes[cols]-1);
+      STR_WITH_MAXSIZE_TO_VARSTR(pWrite, pDnode->dnodeEp, pShow->bytes[cols] - 1);
       cols++;
 
       pWrite = data + pShow->offset[cols] * rows + pShow->bytes[cols] * numOfRows;
-      switch (moduleType) {
-        case TSDB_MOD_MNODE:
-          strcpy(pWrite, "mnode");
-          break;
-        case TSDB_MOD_HTTP:
-          strcpy(pWrite, "http");
-          break;
-        case TSDB_MOD_MONITOR:
-          strcpy(pWrite, "monitor");
-          break;
-        default:
-          strcpy(pWrite, "unknown");
-      }
+      STR_WITH_MAXSIZE_TO_VARSTR(pWrite, moduleName[moduleType], pShow->bytes[cols]);
       cols++;
 
       pWrite = data + pShow->offset[cols] * rows + pShow->bytes[cols] * numOfRows;
       bool enable = mnodeCheckModuleInDnode(pDnode, moduleType);
-      strcpy(pWrite, enable ? "enable" : "disable");
+
+      char* v = enable? "enable":"disable";
+      STR_TO_VARSTR(pWrite, v);
       cols++;
 
       numOfRows++;
@@ -862,13 +854,13 @@ static int32_t mnodeGetConfigMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *p
 
   pShow->bytes[cols] = TSDB_CFG_OPTION_LEN + VARSTR_HEADER_SIZE;
   pSchema[cols].type = TSDB_DATA_TYPE_BINARY;
-  strcpy(pSchema[cols].name, "config name");
+  tstrncpy(pSchema[cols].name, "name", sizeof(pSchema[cols].name));
   pSchema[cols].bytes = htons(pShow->bytes[cols]);
   cols++;
 
   pShow->bytes[cols] = TSDB_CFG_VALUE_LEN + VARSTR_HEADER_SIZE;
   pSchema[cols].type = TSDB_DATA_TYPE_BINARY;
-  strcpy(pSchema[cols].name, "config value");
+  tstrncpy(pSchema[cols].name, "value", sizeof(pSchema[cols].name));
   pSchema[cols].bytes = htons(pShow->bytes[cols]);
   cols++;
 
@@ -903,27 +895,32 @@ static int32_t mnodeRetrieveConfigs(SShowObj *pShow, char *data, int32_t rows, v
     int32_t   cols = 0;
 
     pWrite = data + pShow->offset[cols] * rows + pShow->bytes[cols] * numOfRows;
-    snprintf(pWrite, TSDB_CFG_OPTION_LEN, "%s", cfg->option);
+    STR_WITH_MAXSIZE_TO_VARSTR(pWrite, cfg->option, TSDB_CFG_OPTION_LEN);
+
     cols++;
+    int32_t t = 0;
 
     pWrite = data + pShow->offset[cols] * rows + pShow->bytes[cols] * numOfRows;
     switch (cfg->valType) {
       case TAOS_CFG_VTYPE_INT16:
-        snprintf(pWrite, TSDB_CFG_VALUE_LEN, "%d", *((int16_t *)cfg->ptr));
+        t = snprintf(varDataVal(pWrite), TSDB_CFG_VALUE_LEN, "%d", *((int16_t *)cfg->ptr));
+        varDataSetLen(pWrite, t);
         numOfRows++;
         break;
       case TAOS_CFG_VTYPE_INT32:
-        snprintf(pWrite, TSDB_CFG_VALUE_LEN, "%d", *((int32_t *)cfg->ptr));
+        t = snprintf(varDataVal(pWrite), TSDB_CFG_VALUE_LEN, "%d", *((int32_t *)cfg->ptr));
+        varDataSetLen(pWrite, t);
         numOfRows++;
         break;
       case TAOS_CFG_VTYPE_FLOAT:
-        snprintf(pWrite, TSDB_CFG_VALUE_LEN, "%f", *((float *)cfg->ptr));
+        t = snprintf(varDataVal(pWrite), TSDB_CFG_VALUE_LEN, "%f", *((float *)cfg->ptr));
+        varDataSetLen(pWrite, t);
         numOfRows++;
         break;
       case TAOS_CFG_VTYPE_STRING:
       case TAOS_CFG_VTYPE_IPSTR:
       case TAOS_CFG_VTYPE_DIRECTORY:
-        snprintf(pWrite, TSDB_CFG_VALUE_LEN, "%s", (char *)cfg->ptr);
+        STR_WITH_MAXSIZE_TO_VARSTR(pWrite, cfg->ptr, TSDB_CFG_VALUE_LEN);
         numOfRows++;
         break;
       default:
diff --git a/src/mnode/src/mnodeProfile.c b/src/mnode/src/mnodeProfile.c
index 34147f2e4b..06f992c26a 100644
--- a/src/mnode/src/mnodeProfile.c
+++ b/src/mnode/src/mnodeProfile.c
@@ -100,7 +100,7 @@ SConnObj *mnodeCreateConn(char *user, uint32_t ip, uint16_t port) {
   };
   tstrncpy(connObj.user, user, sizeof(connObj.user));
   
-  SConnObj *pConn = taosCachePut(tsMnodeConnCache, &connId, sizeof(int32_t), &connObj, sizeof(connObj), CONN_KEEP_TIME*1000);
+  SConnObj *pConn = taosCachePut(tsMnodeConnCache, &connId, sizeof(int32_t), &connObj, sizeof(connObj), CONN_KEEP_TIME * 1000);
 
   mDebug("connId:%d, is created, user:%s ip:%s:%u", connId, user, taosIpStr(ip), port);
   return pConn;
diff --git a/src/mnode/src/mnodeShow.c b/src/mnode/src/mnodeShow.c
index 8a84b66a33..e553853658 100644
--- a/src/mnode/src/mnodeShow.c
+++ b/src/mnode/src/mnodeShow.c
@@ -98,7 +98,7 @@ static char *mnodeGetShowType(int32_t showType) {
     case TSDB_MGMT_TABLE_MODULE:  return "show modules";
     case TSDB_MGMT_TABLE_QUERIES: return "show queries";
     case TSDB_MGMT_TABLE_STREAMS: return "show streams";
-    case TSDB_MGMT_TABLE_CONFIGS: return "show configs";
+    case TSDB_MGMT_TABLE_VARIABLES: return "show configs";
     case TSDB_MGMT_TABLE_CONNS:   return "show connections";
     case TSDB_MGMT_TABLE_SCORES:  return "show scores";
     case TSDB_MGMT_TABLE_GRANTS:  return "show grants";
diff --git a/src/os/inc/osSemphone.h b/src/os/inc/osSemphone.h
index fd88d2d798..4280b458a6 100644
--- a/src/os/inc/osSemphone.h
+++ b/src/os/inc/osSemphone.h
@@ -23,7 +23,7 @@ extern "C" {
 #ifndef TAOS_OS_FUNC_SEMPHONE
   #define tsem_t sem_t
   #define tsem_init sem_init
-  #define tsem_wait sem_wait
+  int tsem_wait(tsem_t* sem);
   #define tsem_post sem_post
   #define tsem_destroy sem_destroy
 #endif
diff --git a/src/os/src/detail/osSemphone.c b/src/os/src/detail/osSemphone.c
index 74f8859029..b91888845e 100644
--- a/src/os/src/detail/osSemphone.c
+++ b/src/os/src/detail/osSemphone.c
@@ -16,6 +16,18 @@
 #define _DEFAULT_SOURCE
 #include "os.h"
 
+#ifndef TAOS_OS_FUNC_SEMPHONE
+
+int tsem_wait(tsem_t* sem) {
+  int ret = 0;
+  do {
+    ret = sem_wait(sem);
+  } while (ret != 0 && errno == EINTR);
+  return ret;
+}
+
+#endif
+
 #ifndef TAOS_OS_FUNC_SEMPHONE_PTHREAD
 
 bool    taosCheckPthreadValid(pthread_t thread) { return thread != 0; }
diff --git a/src/query/inc/qAst.h b/src/query/inc/qAst.h
index ec568a6cdb..547616dee6 100644
--- a/src/query/inc/qAst.h
+++ b/src/query/inc/qAst.h
@@ -80,7 +80,7 @@ void tExprTreeTraverse(tExprNode *pExpr, SSkipList *pSkipList, SArray *result, S
 void tExprTreeCalcTraverse(tExprNode *pExprs, int32_t numOfRows, char *pOutput, void *param, int32_t order,
                                 char *(*cb)(void *, const char*, int32_t));
 
-uint8_t getBinaryExprOptr(SSQLToken *pToken);
+uint8_t getBinaryExprOptr(SStrToken *pToken);
 
 void tExprNodeDestroy(tExprNode *pNode, void (*fp)(void *));
 void exprTreeToBinary(SBufferWriter* bw, tExprNode* pExprTree);
diff --git a/src/query/inc/qExecutor.h b/src/query/inc/qExecutor.h
index b5487561b2..7093495763 100644
--- a/src/query/inc/qExecutor.h
+++ b/src/query/inc/qExecutor.h
@@ -33,6 +33,17 @@ struct SColumnFilterElem;
 typedef bool (*__filter_func_t)(struct SColumnFilterElem* pFilter, char* val1, char* val2);
 typedef int32_t (*__block_search_fn_t)(char* data, int32_t num, int64_t key, int32_t order);
 
+typedef struct SPosInfo {
+  int32_t pageId:20;
+  int32_t rowId:12;
+} SPosInfo;
+
+typedef struct SGroupResInfo {
+  int32_t  groupId;
+  int32_t  numOfDataPages;
+  SPosInfo pos;
+} SGroupResInfo;
+
 typedef struct SSqlGroupbyExpr {
   int16_t tableIndex;
   SArray* columnInfo;  // SArray<SColIndex>, group by columns information
@@ -41,21 +52,12 @@ typedef struct SSqlGroupbyExpr {
   int16_t orderType;   // order by type: asc/desc
 } SSqlGroupbyExpr;
 
-typedef struct SPosInfo {
-  int32_t pageId;
-  int32_t rowId;
-} SPosInfo;
-
-typedef struct SWindowStatus {
-  bool closed;
-} SWindowStatus;
-
 typedef struct SWindowResult {
-  uint16_t      numOfRows;   // number of rows of current  time window
-  SWindowStatus status;      // this result status: closed or opened
   SPosInfo      pos;         // Position of current result in disk-based output buffer
+  uint16_t      numOfRows;   // number of rows of current time window
+  bool          closed;      // this result status: closed or opened
   SResultInfo*  resultInfo;  // For each result column, there is a resultInfo
-  STimeWindow   window;      // The time window that current result covers.
+  TSKEY         skey;        // start key of current time window
 } SWindowResult;
 
 /**
@@ -79,6 +81,7 @@ typedef struct SWindowResInfo {
   int64_t        startTime;  // start time of the first time window for sliding query
   int64_t        prevSKey;   // previous (not completed) sliding window start key
   int64_t        threshold;  // threshold to halt query and return the generated results.
+  int64_t        interval;   // time window interval
 } SWindowResInfo;
 
 typedef struct SColumnFilterElem {
@@ -98,7 +101,7 @@ typedef struct STableQueryInfo {  // todo merge with the STableQueryInfo struct
   TSKEY       lastKey;
   int32_t     groupIndex;     // group id in table list
   int16_t     queryRangeSet;  // denote if the query range is set, only available for interval query
-  int64_t     tag;
+  tVariant    tag;
   STimeWindow win;
   STSCursor   cur;
   void*       pTable;         // for retrieve the page id list
@@ -121,8 +124,9 @@ typedef struct SQueryCostInfo {
   uint32_t loadBlockStatis;
   uint32_t discardBlocks;
   uint64_t elapsedTime;
-  uint64_t computTime;
+  uint64_t firstStageMergeTime;
   uint64_t internalSupSize;
+  uint64_t numOfTimeWindows;
 } SQueryCostInfo;
 
 typedef struct SQuery {
@@ -189,21 +193,18 @@ typedef struct SQInfo {
   int64_t          owner; // if it is in execution
   void*            tsdb;
   int32_t          vgId;
-  STableGroupInfo  tableGroupInfo;       // table id list < only includes the STable list>
+  STableGroupInfo  tableGroupInfo;       // table <tid, last_key> list  SArray<STableKeyInfo>
   STableGroupInfo  tableqinfoGroupInfo;  // this is a group array list, including SArray<STableQueryInfo*> structure
   SQueryRuntimeEnv runtimeEnv;
-  int32_t          groupIndex;
-  int32_t          offset;  // offset in group result set of subgroup, todo refactor
   SArray*          arrTableIdInfo;
+  int32_t          groupIndex;
 
   /*
    * the query is executed position on which meter of the whole list.
    * when the index reaches the last one of the list, it means the query is completed.
-   * We later may refactor to remove this attribution by using another flag to denote
-   * whether a multimeter query is completed or not.
    */
   int32_t          tableIndex;
-  int32_t          numOfGroupResultPages;
+  SGroupResInfo    groupResInfo;
   void*            pBuf;        // allocated buffer for STableQueryInfo, sizeof(STableQueryInfo)*numOfTables;
 
   pthread_mutex_t  lock;        // used to synchronize the rsp/query threads
diff --git a/src/query/inc/qSqlparser.h b/src/query/inc/qSqlparser.h
index cd9618b223..69fc0bc7ef 100644
--- a/src/query/inc/qSqlparser.h
+++ b/src/query/inc/qSqlparser.h
@@ -26,7 +26,7 @@ extern "C" {
 #include "tstoken.h"
 #include "tvariant.h"
 
-#define ParseTOKENTYPE SSQLToken
+#define ParseTOKENTYPE SStrToken
 extern char tTokenTypeSwitcher[13];
 
 #define toTSDBType(x)                          \
@@ -71,16 +71,16 @@ typedef struct SQuerySQL {
   struct tSQLExpr *    pWhere;       // where clause [optional]
   tVariantList *       pGroupby;     // groupby clause, only for tags[optional]
   tVariantList *       pSortOrder;   // orderby [optional]
-  SSQLToken            interval;     // interval [optional]
-  SSQLToken            sliding;      // sliding window [optional]
+  SStrToken            interval;     // interval [optional]
+  SStrToken            sliding;      // sliding window [optional]
   SLimitVal            limit;        // limit offset [optional]
   SLimitVal            slimit;       // group limit offset [optional]
   tVariantList *       fillType;     // fill type[optional]
-  SSQLToken            selectToken;  // sql string
+  SStrToken            selectToken;  // sql string
 } SQuerySQL;
 
 typedef struct SCreateTableSQL {
-  struct SSQLToken name;  // meter name, create table [meterName] xxx
+  struct SStrToken name;  // meter name, create table [meterName] xxx
   bool             existCheck;
   
   int8_t           type; // create normal table/from super table/ stream
@@ -90,7 +90,7 @@ typedef struct SCreateTableSQL {
   } colInfo;
   
   struct {
-    SSQLToken     stableName;  // super table name, for using clause
+    SStrToken     stableName;  // super table name, for using clause
     tVariantList *pTagVals;    // create by using metric, tag value
     STagData      tagdata;
   } usingInfo;
@@ -99,7 +99,7 @@ typedef struct SCreateTableSQL {
 } SCreateTableSQL;
 
 typedef struct SAlterTableSQL {
-  SSQLToken     name;
+  SStrToken     name;
   int16_t       type;
   STagData      tagData;
   
@@ -108,7 +108,7 @@ typedef struct SAlterTableSQL {
 } SAlterTableSQL;
 
 typedef struct SCreateDBInfo {
-  SSQLToken dbname;
+  SStrToken dbname;
   int32_t   replica;
   int32_t   cacheBlockSize;
   int32_t   maxTablesPerVnode;
@@ -121,7 +121,7 @@ typedef struct SCreateDBInfo {
   int32_t   walLevel;
   int32_t   quorum;
   int32_t   compressionLevel;
-  SSQLToken precision;
+  SStrToken precision;
   bool      ignoreExists;
   
   tVariantList *keep;
@@ -136,33 +136,33 @@ typedef struct SCreateAcctSQL {
   int64_t   maxStorage;
   int64_t   maxQueryTime;
   int32_t   maxConnections;
-  SSQLToken stat;
+  SStrToken stat;
 } SCreateAcctSQL;
 
 typedef struct SShowInfo {
   uint8_t showType;
-  SSQLToken prefix;
-  SSQLToken pattern;
+  SStrToken prefix;
+  SStrToken pattern;
 } SShowInfo;
 
 typedef struct SUserInfo {
-  SSQLToken user;
-  SSQLToken passwd;
-  SSQLToken privilege;
+  SStrToken user;
+  SStrToken passwd;
+  SStrToken privilege;
   int16_t   type;
 } SUserInfo;
 
 typedef struct tDCLSQL {
   int32_t    nTokens; /* Number of expressions on the list */
   int32_t    nAlloc;  /* Number of entries allocated below */
-  SSQLToken *a;       /* one entry for element */
+  SStrToken *a;       /* one entry for element */
   bool  existsCheck;
   
   union {
     SCreateDBInfo  dbOpt;
     SCreateAcctSQL acctOpt;
     SShowInfo      showOpt;
-    SSQLToken ip;
+    SStrToken ip;
   };
   
   SUserInfo user;
@@ -194,14 +194,14 @@ typedef struct tSQLExpr {
   
   // the full sql string of function(col, param), which is actually the raw
   // field name, since the function name is kept in nSQLOptr already
-  SSQLToken operand;
-  SSQLToken colInfo;            // field id
+  SStrToken operand;
+  SStrToken colInfo;            // field id
   tVariant  val;                // value only for string, float, int
   
   struct tSQLExpr *pLeft;       // left child
   struct tSQLExpr *pRight;      // right child
-  
   struct tSQLExprList *pParam;  // function parameters
+  SStrToken token;              // original sql expr string
 } tSQLExpr;
 
 // used in select clause. select <tSQLExprList> from xxx
@@ -210,6 +210,7 @@ typedef struct tSQLExprItem {
   char *    aliasName;  // alias name, null-terminated string
 } tSQLExprItem;
 
+// todo refactor by using SArray
 typedef struct tSQLExprList {
   int32_t       nExpr;  /* Number of expressions on the list */
   int32_t       nAlloc; /* Number of entries allocated below */
@@ -242,7 +243,7 @@ tVariantList *tVariantListAppend(tVariantList *pList, tVariant *pVar, uint8_t so
 
 tVariantList *tVariantListInsert(tVariantList *pList, tVariant *pVar, uint8_t sortOrder, int32_t index);
 
-tVariantList *tVariantListAppendToken(tVariantList *pList, SSQLToken *pAliasToken, uint8_t sortOrder);
+tVariantList *tVariantListAppendToken(tVariantList *pList, SStrToken *pAliasToken, uint8_t sortOrder);
 void          tVariantListDestroy(tVariantList *pList);
 
 tFieldList *tFieldListAppend(tFieldList *pList, TAOS_FIELD *pField);
@@ -253,61 +254,61 @@ tSQLExpr *tSQLExprCreate(tSQLExpr *pLeft, tSQLExpr *pRight, int32_t optType);
 
 void tSQLExprDestroy(tSQLExpr *);
 
-tSQLExprList *tSQLExprListAppend(tSQLExprList *pList, tSQLExpr *pNode, SSQLToken *pToken);
+tSQLExprList *tSQLExprListAppend(tSQLExprList *pList, tSQLExpr *pNode, SStrToken *pToken);
 
 void tSQLExprListDestroy(tSQLExprList *pList);
 
-SQuerySQL *tSetQuerySQLElems(SSQLToken *pSelectToken, tSQLExprList *pSelection, tVariantList *pFrom, tSQLExpr *pWhere,
-                             tVariantList *pGroupby, tVariantList *pSortOrder, SSQLToken *pInterval,
-                             SSQLToken *pSliding, tVariantList *pFill, SLimitVal *pLimit, SLimitVal *pGLimit);
+SQuerySQL *tSetQuerySQLElems(SStrToken *pSelectToken, tSQLExprList *pSelection, tVariantList *pFrom, tSQLExpr *pWhere,
+                             tVariantList *pGroupby, tVariantList *pSortOrder, SStrToken *pInterval,
+                             SStrToken *pSliding, tVariantList *pFill, SLimitVal *pLimit, SLimitVal *pGLimit);
 
-SCreateTableSQL *tSetCreateSQLElems(tFieldList *pCols, tFieldList *pTags, SSQLToken *pMetricName,
+SCreateTableSQL *tSetCreateSQLElems(tFieldList *pCols, tFieldList *pTags, SStrToken *pMetricName,
                                     tVariantList *pTagVals, SQuerySQL *pSelect, int32_t type);
 
 void      tSQLExprNodeDestroy(tSQLExpr *pExpr);
 tSQLExpr *tSQLExprNodeClone(tSQLExpr *pExpr);
 
-SAlterTableSQL *tAlterTableSQLElems(SSQLToken *pMeterName, tFieldList *pCols, tVariantList *pVals, int32_t type);
+SAlterTableSQL *tAlterTableSQLElems(SStrToken *pMeterName, tFieldList *pCols, tVariantList *pVals, int32_t type);
 
 tSQLExprListList *tSQLListListAppend(tSQLExprListList *pList, tSQLExprList *pExprList);
 
 void destroyAllSelectClause(SSubclauseInfo *pSql);
 void doDestroyQuerySql(SQuerySQL *pSql);
 
-SSqlInfo *      setSQLInfo(SSqlInfo *pInfo, void *pSqlExprInfo, SSQLToken *pMeterName, int32_t type);
+SSqlInfo *      setSQLInfo(SSqlInfo *pInfo, void *pSqlExprInfo, SStrToken *pMeterName, int32_t type);
 SSubclauseInfo *setSubclause(SSubclauseInfo *pClause, void *pSqlExprInfo);
 
 SSubclauseInfo *appendSelectClause(SSubclauseInfo *pInfo, void *pSubclause);
 
-void setCreatedTableName(SSqlInfo *pInfo, SSQLToken *pMeterName, SSQLToken *pIfNotExists);
+void setCreatedTableName(SSqlInfo *pInfo, SStrToken *pMeterName, SStrToken *pIfNotExists);
 
 void SQLInfoDestroy(SSqlInfo *pInfo);
 
 void setDCLSQLElems(SSqlInfo *pInfo, int32_t type, int32_t nParams, ...);
-void setDropDBTableInfo(SSqlInfo *pInfo, int32_t type, SSQLToken* pToken, SSQLToken* existsCheck);
-void setShowOptions(SSqlInfo *pInfo, int32_t type, SSQLToken* prefix, SSQLToken* pPatterns);
+void setDropDBTableInfo(SSqlInfo *pInfo, int32_t type, SStrToken* pToken, SStrToken* existsCheck);
+void setShowOptions(SSqlInfo *pInfo, int32_t type, SStrToken* prefix, SStrToken* pPatterns);
 
-tDCLSQL *tTokenListAppend(tDCLSQL *pTokenList, SSQLToken *pToken);
+tDCLSQL *tTokenListAppend(tDCLSQL *pTokenList, SStrToken *pToken);
 
-void setCreateDBSQL(SSqlInfo *pInfo, int32_t type, SSQLToken *pToken, SCreateDBInfo *pDB, SSQLToken *pIgExists);
+void setCreateDBSQL(SSqlInfo *pInfo, int32_t type, SStrToken *pToken, SCreateDBInfo *pDB, SStrToken *pIgExists);
 
-void setCreateAcctSQL(SSqlInfo *pInfo, int32_t type, SSQLToken *pName, SSQLToken *pPwd, SCreateAcctSQL *pAcctInfo);
-void setCreateUserSQL(SSqlInfo *pInfo, SSQLToken *pName, SSQLToken *pPasswd);
-void setKillSQL(SSqlInfo *pInfo, int32_t type, SSQLToken *ip);
-void setAlterUserSQL(SSqlInfo *pInfo, int16_t type, SSQLToken *pName, SSQLToken* pPwd, SSQLToken *pPrivilege);
+void setCreateAcctSQL(SSqlInfo *pInfo, int32_t type, SStrToken *pName, SStrToken *pPwd, SCreateAcctSQL *pAcctInfo);
+void setCreateUserSQL(SSqlInfo *pInfo, SStrToken *pName, SStrToken *pPasswd);
+void setKillSQL(SSqlInfo *pInfo, int32_t type, SStrToken *ip);
+void setAlterUserSQL(SSqlInfo *pInfo, int16_t type, SStrToken *pName, SStrToken* pPwd, SStrToken *pPrivilege);
 
 void setDefaultCreateDbOption(SCreateDBInfo *pDBInfo);
 
 // prefix show db.tables;
-void setDBName(SSQLToken *pCpxName, SSQLToken *pDB);
+void setDBName(SStrToken *pCpxName, SStrToken *pDB);
 
-tSQLExpr *tSQLExprIdValueCreate(SSQLToken *pToken, int32_t optType);
+tSQLExpr *tSQLExprIdValueCreate(SStrToken *pToken, int32_t optType);
 
-tSQLExpr *tSQLExprCreateFunction(tSQLExprList *pList, SSQLToken *pFuncToken, SSQLToken *endToken, int32_t optType);
+tSQLExpr *tSQLExprCreateFunction(tSQLExprList *pList, SStrToken *pFuncToken, SStrToken *endToken, int32_t optType);
 
-void tSQLSetColumnInfo(TAOS_FIELD *pField, SSQLToken *pName, TAOS_FIELD *pType);
+void tSQLSetColumnInfo(TAOS_FIELD *pField, SStrToken *pName, TAOS_FIELD *pType);
 
-void tSQLSetColumnType(TAOS_FIELD *pField, SSQLToken *pToken);
+void tSQLSetColumnType(TAOS_FIELD *pField, SStrToken *pToken);
 
 void *ParseAlloc(void *(*mallocProc)(size_t));
 
diff --git a/src/query/inc/qTsbuf.h b/src/query/inc/qTsbuf.h
index 59b224e096..46e6f79014 100644
--- a/src/query/inc/qTsbuf.h
+++ b/src/query/inc/qTsbuf.h
@@ -22,6 +22,7 @@ extern "C" {
 
 #include "os.h"
 #include "taosdef.h"
+#include "tvariant.h"
 
 #define MEM_BUF_SIZE (1 << 20)
 #define TS_COMP_FILE_MAGIC 0x87F5EC4C
@@ -42,9 +43,9 @@ typedef struct STSRawBlock {
 } STSRawBlock;
 
 typedef struct STSElem {
-  TSKEY   ts;
-  int64_t tag;
-  int32_t vnode;
+  TSKEY     ts;
+  tVariant  tag;
+  int32_t   vnode;
 } STSElem;
 
 typedef struct STSCursor {
@@ -55,11 +56,11 @@ typedef struct STSCursor {
 } STSCursor;
 
 typedef struct STSBlock {
-  int64_t tag;        // tag value
-  int32_t numOfElem;  // number of elements
-  int32_t compLen;    // size after compressed
-  int32_t padding;    // 0xFFFFFFFF by default, after the payload
-  char*   payload;    // actual data that is compressed
+  tVariant tag;        // tag value
+  int32_t  numOfElem;  // number of elements
+  int32_t  compLen;    // size after compressed
+  int32_t  padding;    // 0xFFFFFFFF by default, after the payload
+  char*    payload;    // actual data that is compressed
 } STSBlock;
 
 /*
@@ -84,8 +85,8 @@ typedef struct STSBuf {
   uint32_t fileSize;
 
   STSVnodeBlockInfoEx* pData;
-  int32_t              numOfAlloc;
-  int32_t              numOfVnodes;
+  uint32_t             numOfAlloc;
+  uint32_t             numOfVnodes;
 
   char*     assistBuf;
   int32_t   bufSize;
@@ -109,7 +110,7 @@ STSBuf* tsBufCreateFromCompBlocks(const char* pData, int32_t numOfBlocks, int32_
 
 void* tsBufDestroy(STSBuf* pTSBuf);
 
-void    tsBufAppend(STSBuf* pTSBuf, int32_t vnodeId, int64_t tag, const char* pData, int32_t len);
+void    tsBufAppend(STSBuf* pTSBuf, int32_t vnodeId, tVariant* tag, const char* pData, int32_t len);
 int32_t tsBufMerge(STSBuf* pDestBuf, const STSBuf* pSrcBuf, int32_t vnodeIdx);
 
 STSBuf* tsBufClone(STSBuf* pTSBuf);
@@ -122,7 +123,7 @@ void    tsBufResetPos(STSBuf* pTSBuf);
 STSElem tsBufGetElem(STSBuf* pTSBuf);
 bool    tsBufNextPos(STSBuf* pTSBuf);
 
-STSElem tsBufGetElemStartPos(STSBuf* pTSBuf, int32_t vnodeId, int64_t tag);
+STSElem tsBufGetElemStartPos(STSBuf* pTSBuf, int32_t vnodeId, tVariant* tag);
 
 STSCursor tsBufGetCursor(STSBuf* pTSBuf);
 void      tsBufSetTraverseOrder(STSBuf* pTSBuf, int32_t order);
diff --git a/src/query/inc/qUtil.h b/src/query/inc/qUtil.h
index b7f57bf1b5..6de3c7c0e5 100644
--- a/src/query/inc/qUtil.h
+++ b/src/query/inc/qUtil.h
@@ -38,7 +38,8 @@ static FORCE_INLINE SWindowResult *getWindowResult(SWindowResInfo *pWindowResInf
   return &pWindowResInfo->pResult[slot];
 }
 
-#define curTimeWindow(_winres)  ((_winres)->curIndex)
+#define curTimeWindowIndex(_winres)        ((_winres)->curIndex)
+#define GET_TIMEWINDOW(_winresInfo, _win)  (STimeWindow) {(_win)->skey, ((_win)->skey + (_winresInfo)->interval - 1)}
 #define GET_ROW_PARAM_FOR_MULTIOUTPUT(_q, tbq, sq) (((tbq) && (!sq))? (_q)->pSelectExpr[1].base.arg->argValue.i64:1)
 
 bool isWindowResClosed(SWindowResInfo *pWindowResInfo, int32_t slot);
diff --git a/src/query/inc/sql.y b/src/query/inc/sql.y
index 2b2a967edf..7500dcba56 100644
--- a/src/query/inc/sql.y
+++ b/src/query/inc/sql.y
@@ -2,8 +2,8 @@
 //usage: lemon sql.y
 %token_prefix TK_
 
-%token_type {SSQLToken}
-%default_type {SSQLToken}
+%token_type {SStrToken}
+%default_type {SStrToken}
 %extra_argument {SSqlInfo* pInfo}
 
 %fallback ID BOOL TINYINT SMALLINT INTEGER BIGINT FLOAT DOUBLE STRING TIMESTAMP BINARY NCHAR.
@@ -73,18 +73,18 @@ cmd ::= SHOW MODULES.    { setShowOptions(pInfo, TSDB_MGMT_TABLE_MODULE, 0, 0);
 cmd ::= SHOW QUERIES.    { setShowOptions(pInfo, TSDB_MGMT_TABLE_QUERIES, 0, 0);  }
 cmd ::= SHOW CONNECTIONS.{ setShowOptions(pInfo, TSDB_MGMT_TABLE_CONNS, 0, 0);}
 cmd ::= SHOW STREAMS.    { setShowOptions(pInfo, TSDB_MGMT_TABLE_STREAMS, 0, 0);  }
-cmd ::= SHOW CONFIGS.    { setShowOptions(pInfo, TSDB_MGMT_TABLE_CONFIGS, 0, 0);  }
+cmd ::= SHOW VARIABLES.  { setShowOptions(pInfo, TSDB_MGMT_TABLE_VARIABLES, 0, 0);  }
 cmd ::= SHOW SCORES.     { setShowOptions(pInfo, TSDB_MGMT_TABLE_SCORES, 0, 0);   }
 cmd ::= SHOW GRANTS.     { setShowOptions(pInfo, TSDB_MGMT_TABLE_GRANTS, 0, 0);   }
 
 cmd ::= SHOW VNODES.                { setShowOptions(pInfo, TSDB_MGMT_TABLE_VNODES, 0, 0); }
 cmd ::= SHOW VNODES IPTOKEN(X).     { setShowOptions(pInfo, TSDB_MGMT_TABLE_VNODES, &X, 0); }
 
-%type dbPrefix {SSQLToken}
+%type dbPrefix {SStrToken}
 dbPrefix(A) ::=.                   {A.n = 0; A.type = 0;}
 dbPrefix(A) ::= ids(X) DOT.        {A = X;  }
 
-%type cpxName {SSQLToken}
+%type cpxName {SStrToken}
 cpxName(A) ::= .             {A.n = 0;  }
 cpxName(A) ::= DOT ids(Y).   {A = Y; A.n += 1;    }
 
@@ -101,19 +101,19 @@ cmd ::= SHOW dbPrefix(X) STABLES.      {
 }
 
 cmd ::= SHOW dbPrefix(X) STABLES LIKE ids(Y).      {
-    SSQLToken token;
+    SStrToken token;
     setDBName(&token, &X);
     setShowOptions(pInfo, TSDB_MGMT_TABLE_METRIC, &token, &Y);
 }
 
 cmd ::= SHOW dbPrefix(X) VGROUPS.    {
-    SSQLToken token;
+    SStrToken token;
     setDBName(&token, &X);
     setShowOptions(pInfo, TSDB_MGMT_TABLE_VGROUP, &token, 0);
 }
 
 cmd ::= SHOW dbPrefix(X) VGROUPS ids(Y).    {
-    SSQLToken token;
+    SStrToken token;
     setDBName(&token, &X);    
     setShowOptions(pInfo, TSDB_MGMT_TABLE_VGROUP, &token, &Y);
 }
@@ -145,7 +145,7 @@ cmd ::= ALTER DNODE ids(X) ids(Y).              { setDCLSQLElems(pInfo, TSDB_SQL
 cmd ::= ALTER DNODE ids(X) ids(Y) ids(Z).       { setDCLSQLElems(pInfo, TSDB_SQL_CFG_DNODE, 3, &X, &Y, &Z);      }
 cmd ::= ALTER LOCAL ids(X).                     { setDCLSQLElems(pInfo, TSDB_SQL_CFG_LOCAL, 1, &X);              }
 cmd ::= ALTER LOCAL ids(X) ids(Y).              { setDCLSQLElems(pInfo, TSDB_SQL_CFG_LOCAL, 2, &X, &Y);          }
-cmd ::= ALTER DATABASE ids(X) alter_db_optr(Y). { SSQLToken t = {0};  setCreateDBSQL(pInfo, TSDB_SQL_ALTER_DB, &X, &Y, &t);}
+cmd ::= ALTER DATABASE ids(X) alter_db_optr(Y). { SStrToken t = {0};  setCreateDBSQL(pInfo, TSDB_SQL_ALTER_DB, &X, &Y, &t);}
 
 cmd ::= ALTER ACCOUNT ids(X) acct_optr(Z).      { setCreateAcctSQL(pInfo, TSDB_SQL_ALTER_ACCT, &X, NULL, &Z);}
 cmd ::= ALTER ACCOUNT ids(X) PASS ids(Y) acct_optr(Z).      { setCreateAcctSQL(pInfo, TSDB_SQL_ALTER_ACCT, &X, &Y, &Z);}
@@ -153,15 +153,15 @@ cmd ::= ALTER ACCOUNT ids(X) PASS ids(Y) acct_optr(Z).      { setCreateAcctSQL(p
 // An IDENTIFIER can be a generic identifier, or one of several keywords.
 // Any non-standard keyword can also be an identifier.
 // And "ids" is an identifer-or-string.
-%type ids {SSQLToken}
+%type ids {SStrToken}
 ids(A) ::= ID(X).        {A = X; }
 ids(A) ::= STRING(X).    {A = X; }
 
-%type ifexists {SSQLToken}
+%type ifexists {SStrToken}
 ifexists(X) ::= IF EXISTS.          {X.n = 1;}
 ifexists(X) ::= .                   {X.n = 0;}
 
-%type ifnotexists {SSQLToken}
+%type ifnotexists {SStrToken}
 ifnotexists(X) ::= IF NOT EXISTS.   {X.n = 1;}
 ifnotexists(X) ::= .                {X.n = 0;}
 
@@ -416,7 +416,7 @@ selcollist(A) ::= sclp(P) STAR. {
 // An option "AS <id>" phrase that can follow one of the expressions that
 // define the result set, or one of the tables in the FROM clause.
 //
-%type as {SSQLToken}
+%type as {SStrToken}
 as(X) ::= AS ids(Y).    { X = Y;    }
 as(X) ::= ids(Y).       { X = Y;    }
 as(X) ::= .             { X.n = 0;  }
@@ -458,10 +458,10 @@ tablelist(A) ::= tablelist(Y) COMMA ids(X) cpxName(Z) ids(F). {
 }
 
 // The value of interval should be the form of "number+[a,s,m,h,d,n,y]" or "now"
-%type tmvar {SSQLToken}
+%type tmvar {SStrToken}
 tmvar(A) ::= VARIABLE(X).   {A = X;}
 
-%type interval_opt {SSQLToken}
+%type interval_opt {SStrToken}
 interval_opt(N) ::= INTERVAL LP tmvar(E) RP.    {N = E;     }
 interval_opt(N) ::= .                           {N.n = 0; N.z = NULL; N.type = 0;   }
 
@@ -482,7 +482,7 @@ fill_opt(N) ::= FILL LP ID(Y) RP.               {
     N = tVariantListAppendToken(NULL, &Y, -1);
 }
 
-%type sliding_opt {SSQLToken}
+%type sliding_opt {SStrToken}
 sliding_opt(K) ::= SLIDING LP tmvar(E) RP.      {K = E;     }
 sliding_opt(K) ::= .                            {K.n = 0; K.z = NULL; K.type = 0;   }
 
diff --git a/src/query/inc/tsqlfunction.h b/src/query/inc/tsqlfunction.h
index 58d2ff260e..65ab82883b 100644
--- a/src/query/inc/tsqlfunction.h
+++ b/src/query/inc/tsqlfunction.h
@@ -91,16 +91,16 @@ extern "C" {
 #define QUERY_COND_REL_PREFIX_IN "IN|"
 #define QUERY_COND_REL_PREFIX_LIKE "LIKE|"
 
-#define QUERY_COND_REL_PREFIX_IN_LEN 3
+#define QUERY_COND_REL_PREFIX_IN_LEN   3
 #define QUERY_COND_REL_PREFIX_LIKE_LEN 5
 
-#define QUERY_ASC_FORWARD_STEP 1
+#define QUERY_ASC_FORWARD_STEP   1
 #define QUERY_DESC_FORWARD_STEP -1
 
 #define GET_FORWARD_DIRECTION_FACTOR(ord) (((ord) == TSDB_ORDER_ASC) ? QUERY_ASC_FORWARD_STEP : QUERY_DESC_FORWARD_STEP)
 
-#define MAX_RETRIEVE_ROWS_IN_INTERVAL_QUERY 10000000
-#define TOP_BOTTOM_QUERY_LIMIT 100
+#define MAX_INTERVAL_TIME_WINDOW 10000000
+#define TOP_BOTTOM_QUERY_LIMIT   100
 
 enum {
   MASTER_SCAN           = 0x0u,
@@ -137,13 +137,13 @@ typedef struct SInterpInfoDetail {
 } SInterpInfoDetail;
 
 typedef struct SResultInfo {
-  int8_t  hasResult;       // result generated, not NULL value
-  bool    initialized;     // output buffer has been initialized
-  bool    complete;        // query has completed
-  bool    superTableQ;     // is super table query
-  int32_t numOfRes;        // num of output result in current buffer
-  int32_t bufLen;          // buffer size
-  void*   interResultBuf;  // output result buffer
+  int8_t   hasResult;       // result generated, not NULL value
+  bool     initialized;   // output buffer has been initialized
+  bool     complete;      // query has completed
+  bool     superTableQ;   // is super table query
+  uint32_t bufLen;       // buffer size
+  uint64_t numOfRes;        // num of output result in current buffer
+  void*    interResultBuf;  // output result buffer
 } SResultInfo;
 
 struct SQLFunctionCtx;
diff --git a/src/query/src/qAst.c b/src/query/src/qAst.c
index afa3618a96..634f014d97 100644
--- a/src/query/src/qAst.c
+++ b/src/query/src/qAst.c
@@ -44,7 +44,7 @@
  * ver 0.3, pipeline filter in the form of: (a+2)/9 > 14
  *
  */
-static tExprNode *tExprNodeCreate(SSchema *pSchema, int32_t numOfCols, SSQLToken *pToken);
+static tExprNode *tExprNodeCreate(SSchema *pSchema, int32_t numOfCols, SStrToken *pToken);
 
 static tExprNode *createSyntaxTree(SSchema *pSchema, int32_t numOfCols, char *str, int32_t *i);
 static void       destroySyntaxTree(tExprNode *);
@@ -103,7 +103,7 @@ static void reviseBinaryExprIfNecessary(tExprNode **pLeft, tExprNode **pRight, u
   }
 }
 
-static tExprNode *tExprNodeCreate(SSchema *pSchema, int32_t numOfCols, SSQLToken *pToken) {
+static tExprNode *tExprNodeCreate(SSchema *pSchema, int32_t numOfCols, SStrToken *pToken) {
   /* if the token is not a value, return false */
   if (pToken->type == TK_RP || (pToken->type != TK_INTEGER && pToken->type != TK_FLOAT && pToken->type != TK_ID &&
                                 pToken->type != TK_TBNAME && pToken->type != TK_STRING && pToken->type != TK_BOOL)) {
@@ -117,7 +117,7 @@ static tExprNode *tExprNodeCreate(SSchema *pSchema, int32_t numOfCols, SSQLToken
     int32_t i = 0;
     if (pToken->type == TK_ID) {
       do {
-        SSQLToken tableToken = {0};
+        SStrToken tableToken = {0};
         extractTableNameFromToken(pToken, &tableToken);
 
         size_t len = strlen(pSchema[i].name);
@@ -157,7 +157,7 @@ static tExprNode *tExprNodeCreate(SSchema *pSchema, int32_t numOfCols, SSQLToken
   return pNode;
 }
 
-uint8_t getBinaryExprOptr(SSQLToken *pToken) {
+uint8_t getBinaryExprOptr(SStrToken *pToken) {
   switch (pToken->type) {
     case TK_LT:
       return TSDB_RELATION_LESS;
@@ -234,7 +234,7 @@ uint8_t isQueryOnPrimaryKey(const char *primaryColumnName, const tExprNode *pLef
 }
 
 static tExprNode *createSyntaxTree(SSchema *pSchema, int32_t numOfCols, char *str, int32_t *i) {
-  SSQLToken t0 = tStrGetToken(str, i, false, 0, NULL);
+  SStrToken t0 = tStrGetToken(str, i, false, 0, NULL);
   if (t0.n == 0) {
     return NULL;
   }
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index 03b699c1b8..4e2e31d269 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -27,7 +27,8 @@
 #include "query.h"
 #include "queryLog.h"
 #include "tlosertree.h"
-#include "tscompression.h"
+
+#define MAX_ROWS_PER_RESBUF_PAGE  ((1u<<12) - 1)
 
 /**
  * check if the primary column is load by default, otherwise, the program will
@@ -35,6 +36,9 @@
  */
 #define Q_STATUS_EQUAL(p, s)  (((p) & (s)) != 0)
 #define TSDB_COL_IS_TAG(f)    (((f)&TSDB_COL_TAG) != 0)
+#define TSDB_COL_IS_NORMAL_COL(f)    ((f) == TSDB_COL_NORMAL)
+#define TSDB_COL_IS_UD_COL(f)   ((f) == TSDB_COL_UDC)
+
 #define QUERY_IS_ASC_QUERY(q) (GET_FORWARD_DIRECTION_FACTOR((q)->order.order) == QUERY_ASC_FORWARD_STEP)
 
 #define IS_MASTER_SCAN(runtime)        ((runtime)->scanFlag == MASTER_SCAN)
@@ -93,7 +97,8 @@ typedef struct {
 #if 0
 static UNUSED_FUNC void *u_malloc (size_t __size) {
   uint32_t v = rand();
-  if (v % 5 <= 1) {
+
+  if (v % 1000 <= 0) {
     return NULL;
   } else {
     return malloc(__size);
@@ -102,15 +107,25 @@ static UNUSED_FUNC void *u_malloc (size_t __size) {
 
 static UNUSED_FUNC void* u_calloc(size_t num, size_t __size) {
   uint32_t v = rand();
-  if (v % 5 <= 1) {
+  if (v % 1000 <= 0) {
     return NULL;
   } else {
     return calloc(num, __size);
   }
 }
 
+static UNUSED_FUNC void* u_realloc(void* p, size_t __size) {
+  uint32_t v = rand();
+  if (v % 5 <= 1) {
+    return NULL;
+  } else {
+    return realloc(p, __size);
+  }
+}
+
 #define calloc  u_calloc
 #define malloc  u_malloc
+#define realloc u_realloc
 #endif
 
 #define CLEAR_QUERY_STATUS(q, st)   ((q)->status &= (~(st)))
@@ -151,7 +166,7 @@ static bool hasMainOutput(SQuery *pQuery);
 static void buildTagQueryResult(SQInfo *pQInfo);
 
 static int32_t setAdditionalInfo(SQInfo *pQInfo, void *pTable, STableQueryInfo *pTableQueryInfo);
-static int32_t flushFromResultBuf(SQInfo *pQInfo);
+static int32_t flushFromResultBuf(SQueryRuntimeEnv* pRuntimeEnv, SGroupResInfo* pGroupResInfo);
 
 bool doFilterData(SQuery *pQuery, int32_t elemPos) {
   for (int32_t k = 0; k < pQuery->numOfFilterCols; ++k) {
@@ -212,22 +227,22 @@ int64_t getNumOfResult(SQueryRuntimeEnv *pRuntimeEnv) {
  */
 void updateNumOfResult(SQueryRuntimeEnv *pRuntimeEnv, int32_t numOfRes) {
   SQuery *pQuery = pRuntimeEnv->pQuery;
-  
+
   for (int32_t j = 0; j < pQuery->numOfOutput; ++j) {
     SResultInfo *pResInfo = GET_RES_INFO(&pRuntimeEnv->pCtx[j]);
-    
+
     int16_t functionId = pRuntimeEnv->pCtx[j].functionId;
     if (functionId == TSDB_FUNC_TS || functionId == TSDB_FUNC_TAG || functionId == TSDB_FUNC_TAGPRJ ||
         functionId == TSDB_FUNC_TS_DUMMY) {
       continue;
     }
-    
+
     assert(pResInfo->numOfRes > numOfRes);
     pResInfo->numOfRes = numOfRes;
   }
 }
 
-static int32_t getGroupResultId(int32_t groupIndex) {
+static UNUSED_FUNC int32_t getGroupResultId(int32_t groupIndex) {
   int32_t base = 20000000;
   return base + (groupIndex * 10000);
 }
@@ -315,10 +330,10 @@ bool isTSCompQuery(SQuery *pQuery) { return pQuery->pSelectExpr[0].base.function
 static bool limitResults(SQueryRuntimeEnv* pRuntimeEnv) {
   SQInfo* pQInfo = GET_QINFO_ADDR(pRuntimeEnv);
   SQuery* pQuery = pRuntimeEnv->pQuery;
-  
+
   if ((pQuery->limit.limit > 0) && (pQuery->rec.total + pQuery->rec.rows > pQuery->limit.limit)) {
     pQuery->rec.rows = pQuery->limit.limit - pQuery->rec.total;
-    
+
     qDebug("QInfo:%p discard remain data due to result limitation, limit:%"PRId64", current return:%" PRId64 ", total:%"PRId64,
         pQInfo, pQuery->limit.limit, pQuery->rec.rows, pQuery->rec.total + pQuery->rec.rows);
     assert(pQuery->rec.rows >= 0);
@@ -371,14 +386,14 @@ static bool hasTagValOutput(SQuery* pQuery) {
  * @return
  */
 static bool hasNullValue(SColIndex* pColIndex, SDataStatis *pStatis, SDataStatis **pColStatis) {
-  if (pStatis != NULL && !TSDB_COL_IS_TAG(pColIndex->flag)) {
+  if (pStatis != NULL && TSDB_COL_IS_NORMAL_COL(pColIndex->flag)) {
     *pColStatis = &pStatis[pColIndex->colIndex];
     assert((*pColStatis)->colId == pColIndex->colId);
   } else {
     *pColStatis = NULL;
   }
 
-  if (TSDB_COL_IS_TAG(pColIndex->flag) || pColIndex->colId == PRIMARYKEY_TIMESTAMP_COL_INDEX) {
+  if (TSDB_COL_IS_TAG(pColIndex->flag) || TSDB_COL_IS_UD_COL(pColIndex->flag) || pColIndex->colId == PRIMARYKEY_TIMESTAMP_COL_INDEX) {
     return false;
   }
 
@@ -412,6 +427,7 @@ static SWindowResult *doSetTimeWindowFromKey(SQueryRuntimeEnv *pRuntimeEnv, SWin
 
       char *t = realloc(pWindowResInfo->pResult, (size_t)(newCap * sizeof(SWindowResult)));
       pRuntimeEnv->summary.internalSupSize += (newCap - pWindowResInfo->capacity) * sizeof(SWindowResult);
+      pRuntimeEnv->summary.numOfTimeWindows += (newCap - pWindowResInfo->capacity);
 
       if (t == NULL) {
         longjmp(pRuntimeEnv->env, TSDB_CODE_QRY_OUT_OF_MEMORY);
@@ -425,7 +441,10 @@ static SWindowResult *doSetTimeWindowFromKey(SQueryRuntimeEnv *pRuntimeEnv, SWin
       pRuntimeEnv->summary.internalSupSize += (pQuery->numOfOutput * sizeof(SResultInfo) + pRuntimeEnv->interBufSize) * inc;
 
       for (int32_t i = pWindowResInfo->capacity; i < newCap; ++i) {
-        createQueryResultInfo(pQuery, &pWindowResInfo->pResult[i], pRuntimeEnv->stableQuery, pRuntimeEnv->interBufSize);
+        int32_t ret = createQueryResultInfo(pQuery, &pWindowResInfo->pResult[i], pRuntimeEnv->stableQuery, pRuntimeEnv->interBufSize);
+        if (ret != TSDB_CODE_SUCCESS) {
+          longjmp(pRuntimeEnv->env, TSDB_CODE_QRY_OUT_OF_MEMORY);
+        }
       }
 
       pWindowResInfo->capacity = (int32_t)newCap;
@@ -436,6 +455,11 @@ static SWindowResult *doSetTimeWindowFromKey(SQueryRuntimeEnv *pRuntimeEnv, SWin
     taosHashPut(pWindowResInfo->hashList, pData, bytes, (char *)&pWindowResInfo->curIndex, sizeof(int32_t));
   }
 
+  // too many time window in query
+  if (pWindowResInfo->size > MAX_INTERVAL_TIME_WINDOW) {
+    longjmp(pRuntimeEnv->env, TSDB_CODE_QRY_TOO_MANY_TIMEWINDOW);
+  }
+
   return getWindowResult(pWindowResInfo, pWindowResInfo->curIndex);
 }
 
@@ -447,8 +471,9 @@ static STimeWindow getActiveTimeWindow(SWindowResInfo *pWindowResInfo, int64_t t
     w.skey = pWindowResInfo->prevSKey;
     w.ekey = w.skey + pQuery->intervalTime - 1;
   } else {
-    int32_t slot = curTimeWindow(pWindowResInfo);
-    w = getWindowResult(pWindowResInfo, slot)->window;
+    int32_t slot = curTimeWindowIndex(pWindowResInfo);
+    SWindowResult* pWindowRes = getWindowResult(pWindowResInfo, slot);
+    w = GET_TIMEWINDOW(pWindowResInfo, pWindowRes);
   }
 
   if (w.skey > ts || w.ekey < ts) {
@@ -549,15 +574,15 @@ static int32_t setWindowOutputBufByKey(SQueryRuntimeEnv *pRuntimeEnv, SWindowRes
   }
 
   // set time window for current result
-  pWindowRes->window = *win;
+  pWindowRes->skey = win->skey;
 
   setWindowResOutputBufInitCtx(pRuntimeEnv, pWindowRes);
   return TSDB_CODE_SUCCESS;
 }
 
-static SWindowStatus *getTimeWindowResStatus(SWindowResInfo *pWindowResInfo, int32_t slot) {
+static bool getTimeWindowResStatus(SWindowResInfo *pWindowResInfo, int32_t slot) {
   assert(slot >= 0 && slot < pWindowResInfo->size);
-  return &pWindowResInfo->pResult[slot].status;
+  return pWindowResInfo->pResult[slot].closed;
 }
 
 static FORCE_INLINE int32_t getForwardStepsInBlock(int32_t numOfRows, __block_search_fn_t searchFn, TSKEY ekey, int16_t pos,
@@ -599,7 +624,7 @@ static int32_t doCheckQueryCompleted(SQueryRuntimeEnv *pRuntimeEnv, TSKEY lastKe
 
   // no qualified results exist, abort check
   int32_t numOfClosed = 0;
-  
+
   if (pWindowResInfo->size == 0) {
     return pWindowResInfo->size;
   }
@@ -617,16 +642,17 @@ static int32_t doCheckQueryCompleted(SQueryRuntimeEnv *pRuntimeEnv, TSKEY lastKe
 
     for (i = 0; i < pWindowResInfo->size; ++i) {
       SWindowResult *pResult = &pWindowResInfo->pResult[i];
-      if (pResult->status.closed) {
+      if (pResult->closed) {
         numOfClosed += 1;
         continue;
       }
 
-      if ((pResult->window.ekey <= lastKey && QUERY_IS_ASC_QUERY(pQuery)) ||
-          (pResult->window.skey >= lastKey && !QUERY_IS_ASC_QUERY(pQuery))) {
+      TSKEY ekey = pResult->skey + pWindowResInfo->interval;
+      if ((ekey <= lastKey && QUERY_IS_ASC_QUERY(pQuery)) ||
+          (pResult->skey >= lastKey && !QUERY_IS_ASC_QUERY(pQuery))) {
         closeTimeWindow(pWindowResInfo, i);
       } else {
-        skey = pResult->window.skey;
+        skey = pResult->skey;
         break;
       }
     }
@@ -639,26 +665,26 @@ static int32_t doCheckQueryCompleted(SQueryRuntimeEnv *pRuntimeEnv, TSKEY lastKe
       pWindowResInfo->curIndex = i;
     }
 
-    pWindowResInfo->prevSKey = pWindowResInfo->pResult[pWindowResInfo->curIndex].window.skey;
+    pWindowResInfo->prevSKey = pWindowResInfo->pResult[pWindowResInfo->curIndex].skey;
 
     // the number of completed slots are larger than the threshold, return current generated results to client.
     if (numOfClosed > pWindowResInfo->threshold) {
       qDebug("QInfo:%p total result window:%d closed:%d, reached the output threshold %d, return",
           GET_QINFO_ADDR(pRuntimeEnv), pWindowResInfo->size, numOfClosed, pQuery->rec.threshold);
-      
+
       setQueryStatus(pQuery, QUERY_RESBUF_FULL);
     } else {
       qDebug("QInfo:%p total result window:%d already closed:%d", GET_QINFO_ADDR(pRuntimeEnv), pWindowResInfo->size,
              numOfClosed);
     }
   }
-  
+
   // output has reached the limitation, set query completed
   if (pQuery->limit.limit > 0 && (pQuery->limit.limit + pQuery->limit.offset) <= numOfClosed &&
       pRuntimeEnv->scanFlag == MASTER_SCAN) {
     setQueryStatus(pQuery, QUERY_COMPLETED);
   }
-  
+
   assert(pWindowResInfo->prevSKey != TSKEY_INITIAL_VAL);
   return numOfClosed;
 }
@@ -672,7 +698,7 @@ static int32_t getNumOfRowsInTimeWindow(SQuery *pQuery, SDataBlockInfo *pDataBlo
   int32_t step = GET_FORWARD_DIRECTION_FACTOR(order);
 
   STableQueryInfo* item = pQuery->current;
-  
+
   if (QUERY_IS_ASC_QUERY(pQuery)) {
     if (ekey < pDataBlockInfo->window.ekey) {
       num = getForwardStepsInBlock(pDataBlockInfo->rows, searchFn, ekey, startPos, order, pPrimaryColumn);
@@ -703,12 +729,12 @@ static int32_t getNumOfRowsInTimeWindow(SQuery *pQuery, SDataBlockInfo *pDataBlo
   return num;
 }
 
-static void doBlockwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SWindowStatus *pStatus, STimeWindow *pWin,
+static void doBlockwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, bool closed, STimeWindow *pWin,
                                       int32_t offset, int32_t forwardStep, TSKEY *tsBuf, int32_t numOfTotal) {
   SQuery *        pQuery = pRuntimeEnv->pQuery;
   SQLFunctionCtx *pCtx = pRuntimeEnv->pCtx;
 
-  if (IS_MASTER_SCAN(pRuntimeEnv) || pStatus->closed) {
+  if (IS_MASTER_SCAN(pRuntimeEnv) || closed) {
     for (int32_t k = 0; k < pQuery->numOfOutput; ++k) {
       int32_t functionId = pQuery->pSelectExpr[k].base.functionId;
 
@@ -732,12 +758,11 @@ static void doBlockwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SWindowStat
   }
 }
 
-static void doRowwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SWindowStatus *pStatus, STimeWindow *pWin,
-                                    int32_t offset) {
+static void doRowwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, bool closed, STimeWindow *pWin, int32_t offset) {
   SQuery *        pQuery = pRuntimeEnv->pQuery;
   SQLFunctionCtx *pCtx = pRuntimeEnv->pCtx;
 
-  if (IS_MASTER_SCAN(pRuntimeEnv) || pStatus->closed) {
+  if (IS_MASTER_SCAN(pRuntimeEnv) || closed) {
     for (int32_t k = 0; k < pQuery->numOfOutput; ++k) {
       pCtx[k].nStartQueryTimestamp = pWin->skey;
 
@@ -822,14 +847,14 @@ static FORCE_INLINE TSKEY reviseWindowEkey(SQuery *pQuery, STimeWindow *pWindow)
 //todo binary search
 static void* getDataBlockImpl(SArray* pDataBlock, int32_t colId) {
   int32_t numOfCols = (int32_t)taosArrayGetSize(pDataBlock);
-  
+
   for (int32_t i = 0; i < numOfCols; ++i) {
     SColumnInfoData *p = taosArrayGet(pDataBlock, i);
     if (colId == p->info.colId) {
       return p->pData;
     }
   }
-  
+
   return NULL;
 }
 
@@ -879,19 +904,19 @@ static char *getDataBlock(SQueryRuntimeEnv *pRuntimeEnv, SArithmeticSupport *sas
       }
 
       assert(dataBlock != NULL);
-      sas->data[i] = dataBlock/* + pQuery->colList[i].bytes*/;  // start from the offset
+      sas->data[i] = dataBlock;  // start from the offset
     }
 
   } else {  // other type of query function
     SColIndex *pCol = &pQuery->pSelectExpr[col].base.colInfo;
-    if (TSDB_COL_IS_TAG(pCol->flag)) {
-      dataBlock = NULL;
-    } else {
+    if (TSDB_COL_IS_NORMAL_COL(pCol->flag)) {
       SColIndex* pColIndex = &pQuery->pSelectExpr[col].base.colInfo;
       SColumnInfoData *p = taosArrayGet(pDataBlock, pColIndex->colIndex);
       assert(p->info.colId == pColIndex->colId);
 
       dataBlock = p->pData;
+    } else {
+      dataBlock = NULL;
     }
   }
 
@@ -958,7 +983,7 @@ static void blockwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *
       TSKEY ekey = reviseWindowEkey(pQuery, &win);
       forwardStep = getNumOfRowsInTimeWindow(pQuery, pDataBlockInfo, tsCols, pQuery->pos, ekey, searchFn, true);
 
-      SWindowStatus *pStatus = getTimeWindowResStatus(pWindowResInfo, curTimeWindow(pWindowResInfo));
+      bool pStatus = getTimeWindowResStatus(pWindowResInfo, curTimeWindowIndex(pWindowResInfo));
       doBlockwiseApplyFunctions(pRuntimeEnv, pStatus, &win, startPos, forwardStep, tsCols, pDataBlockInfo->rows);
     }
 
@@ -986,8 +1011,8 @@ static void blockwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *
       TSKEY ekey = reviseWindowEkey(pQuery, &nextWin);
       forwardStep = getNumOfRowsInTimeWindow(pQuery, pDataBlockInfo, tsCols, startPos, ekey, searchFn, true);
 
-      SWindowStatus *pStatus = getTimeWindowResStatus(pWindowResInfo, curTimeWindow(pWindowResInfo));
-      doBlockwiseApplyFunctions(pRuntimeEnv, pStatus, &nextWin, startPos, forwardStep, tsCols, pDataBlockInfo->rows);
+      bool closed = getTimeWindowResStatus(pWindowResInfo, curTimeWindowIndex(pWindowResInfo));
+      doBlockwiseApplyFunctions(pRuntimeEnv, closed, &nextWin, startPos, forwardStep, tsCols, pDataBlockInfo->rows);
     }
 
     pWindowResInfo->curIndex = index;
@@ -1040,8 +1065,8 @@ static int32_t setGroupResultOutputBuf(SQueryRuntimeEnv *pRuntimeEnv, char *pDat
     return -1;
   }
 
-  pWindowRes->window.skey = v;
-  pWindowRes->window.ekey = v;
+  pWindowRes->skey = v;
+  assert(pRuntimeEnv->windowResInfo.interval == 0);
 
   if (pWindowRes->pos.pageId == -1) {
     int32_t ret = addNewWindowResultBuf(pWindowRes, pResultBuf, GROUPRESULTID, pRuntimeEnv->numOfRowsPerPage);
@@ -1103,7 +1128,7 @@ static int32_t doTSJoinFilter(SQueryRuntimeEnv *pRuntimeEnv, int32_t offset) {
   SQLFunctionCtx *pCtx = pRuntimeEnv->pCtx;
 
   // compare tag first
-  if (pCtx[0].tag.i64Key != elem.tag) {
+  if (tVariantCompare(&pCtx[0].tag, &elem.tag) != 0) {
     return TS_JOIN_TAG_NOT_EQUALS;
   }
 
@@ -1140,7 +1165,7 @@ static bool functionNeedToExecute(SQueryRuntimeEnv *pRuntimeEnv, SQLFunctionCtx
   if (functionId == TSDB_FUNC_TS) {
     return true;
   }
-  
+
   if (pResInfo->complete || functionId == TSDB_FUNC_TAG_DUMMY || functionId == TSDB_FUNC_TS_DUMMY) {
     return false;
   }
@@ -1247,8 +1272,8 @@ static void rowwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *pS
         continue;
       }
 
-      SWindowStatus *pStatus = getTimeWindowResStatus(pWindowResInfo, curTimeWindow(pWindowResInfo));
-      doRowwiseApplyFunctions(pRuntimeEnv, pStatus, &win, offset);
+      bool closed = getTimeWindowResStatus(pWindowResInfo, curTimeWindowIndex(pWindowResInfo));
+      doRowwiseApplyFunctions(pRuntimeEnv, closed, &win, offset);
 
       STimeWindow nextWin = win;
       int32_t     index = pWindowResInfo->curIndex;
@@ -1271,8 +1296,8 @@ static void rowwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *pS
         }
 
         if (hasTimeWindow) {
-          pStatus = getTimeWindowResStatus(pWindowResInfo, curTimeWindow(pWindowResInfo));
-          doRowwiseApplyFunctions(pRuntimeEnv, pStatus, &nextWin, offset);
+          closed = getTimeWindowResStatus(pWindowResInfo, curTimeWindowIndex(pWindowResInfo));
+          doRowwiseApplyFunctions(pRuntimeEnv, closed, &nextWin, offset);
         }
       }
 
@@ -1327,10 +1352,10 @@ static void rowwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *pS
 static int32_t tableApplyFunctionsOnBlock(SQueryRuntimeEnv *pRuntimeEnv, SDataBlockInfo *pDataBlockInfo,
                                           SDataStatis *pStatis, __block_search_fn_t searchFn, SArray *pDataBlock) {
   SQuery *pQuery = pRuntimeEnv->pQuery;
-  
+
   STableQueryInfo* pTableQInfo = pQuery->current;
   SWindowResInfo*  pWindowResInfo = &pRuntimeEnv->windowResInfo;
-  
+
   if (pQuery->numOfFilterCols > 0 || pRuntimeEnv->pTSBuf != NULL || pRuntimeEnv->groupbyNormalCol) {
     rowwiseApplyFunctions(pRuntimeEnv, pStatis, pDataBlockInfo, pWindowResInfo, pDataBlock);
   } else {
@@ -1373,10 +1398,10 @@ static int32_t tableApplyFunctionsOnBlock(SQueryRuntimeEnv *pRuntimeEnv, SDataBl
 
 void setExecParams(SQuery *pQuery, SQLFunctionCtx *pCtx, void* inputData, TSKEY *tsCol, SDataBlockInfo* pBlockInfo,
                    SDataStatis *pStatis, void *param, int32_t colIndex) {
-  
+
   int32_t functionId = pQuery->pSelectExpr[colIndex].base.functionId;
   int32_t colId = pQuery->pSelectExpr[colIndex].base.colInfo.colId;
-  
+
   SDataStatis *tpField = NULL;
   pCtx->hasNull = hasNullValue(&pQuery->pSelectExpr[colIndex].base.colInfo, pStatis, &tpField);
   pCtx->aInputElemBuf = inputData;
@@ -1432,7 +1457,7 @@ void setExecParams(SQuery *pQuery, SQLFunctionCtx *pCtx, void* inputData, TSKEY
     pInterpInfo->type = (int8_t)pQuery->fillType;
     pInterpInfo->ts = pQuery->window.skey;
     pInterpInfo->primaryCol = (colId == PRIMARYKEY_TIMESTAMP_COL_INDEX);
-  
+
     if (pQuery->fillVal != NULL) {
       if (isNull((const char*) &pQuery->fillVal[colIndex], pCtx->inputType)) {
         pCtx->param[1].nType = TSDB_DATA_TYPE_NULL;
@@ -1459,19 +1484,22 @@ void setExecParams(SQuery *pQuery, SQLFunctionCtx *pCtx, void* inputData, TSKEY
 }
 
 // set the output buffer for the selectivity + tag query
-static void setCtxTagColumnInfo(SQueryRuntimeEnv *pRuntimeEnv, SQLFunctionCtx *pCtx) {
+static int32_t setCtxTagColumnInfo(SQueryRuntimeEnv *pRuntimeEnv, SQLFunctionCtx *pCtx) {
   SQuery* pQuery = pRuntimeEnv->pQuery;
 
   if (isSelectivityWithTagsQuery(pQuery)) {
     int32_t num = 0;
     int16_t tagLen = 0;
-    
+
     SQLFunctionCtx *p = NULL;
     SQLFunctionCtx **pTagCtx = calloc(pQuery->numOfOutput, POINTER_BYTES);
+    if (pTagCtx == NULL) {
+      return TSDB_CODE_QRY_OUT_OF_MEMORY;
+    }
 
     for (int32_t i = 0; i < pQuery->numOfOutput; ++i) {
       SSqlFuncMsg *pSqlFuncMsg = &pQuery->pSelectExpr[i].base;
-      
+
       if (pSqlFuncMsg->functionId == TSDB_FUNC_TAG_DUMMY || pSqlFuncMsg->functionId == TSDB_FUNC_TS_DUMMY) {
         tagLen += pCtx[i].outputBytes;
         pTagCtx[num++] = &pCtx[i];
@@ -1490,9 +1518,11 @@ static void setCtxTagColumnInfo(SQueryRuntimeEnv *pRuntimeEnv, SQLFunctionCtx *p
       p->tagInfo.numOfTagCols = num;
       p->tagInfo.tagsLen = tagLen;
     } else {
-      taosTFree(pTagCtx); 
+      taosTFree(pTagCtx);
     }
   }
+
+  return TSDB_CODE_SUCCESS;
 }
 
 static FORCE_INLINE void setWindowResultInfo(SResultInfo *pResultInfo, SQuery *pQuery, bool isStableQuery, char* buf) {
@@ -1536,12 +1566,14 @@ static int32_t setupQueryRuntimeEnv(SQueryRuntimeEnv *pRuntimeEnv, int16_t order
         pCtx->inputBytes = pQuery->tagColList[index].bytes;
         pCtx->inputType = pQuery->tagColList[index].type;
       }
-      
+    } else if (TSDB_COL_IS_UD_COL(pIndex->flag)) {
+      pCtx->inputBytes = pSqlFuncMsg->arg[0].argBytes;
+      pCtx->inputType = pSqlFuncMsg->arg[0].argType;
     } else {
       pCtx->inputBytes = pQuery->colList[index].bytes;
       pCtx->inputType = pQuery->colList[index].type;
     }
-  
+
     assert(isValidDataType(pCtx->inputType));
     pCtx->ptsOutputBuf = NULL;
 
@@ -1556,7 +1588,7 @@ static int32_t setupQueryRuntimeEnv(SQueryRuntimeEnv *pRuntimeEnv, int16_t order
       int16_t type = pSqlFuncMsg->arg[j].argType;
       int16_t bytes = pSqlFuncMsg->arg[j].argBytes;
       if (type == TSDB_DATA_TYPE_BINARY || type == TSDB_DATA_TYPE_NCHAR) {
-        tVariantCreateFromBinary(&pCtx->param[j], pSqlFuncMsg->arg->argValue.pz, bytes, type);
+        tVariantCreateFromBinary(&pCtx->param[j], pSqlFuncMsg->arg[j].argValue.pz, bytes, type);
       } else {
         tVariantCreateFromBinary(&pCtx->param[j], (char *)&pSqlFuncMsg->arg[j].argValue.i64, bytes, type);
       }
@@ -1592,7 +1624,9 @@ static int32_t setupQueryRuntimeEnv(SQueryRuntimeEnv *pRuntimeEnv, int16_t order
     resetCtxOutputBuf(pRuntimeEnv);
   }
 
-  setCtxTagColumnInfo(pRuntimeEnv, pRuntimeEnv->pCtx);
+  if (setCtxTagColumnInfo(pRuntimeEnv, pRuntimeEnv->pCtx) != TSDB_CODE_SUCCESS) {
+    goto _clean;
+  }
 
   qDebug("QInfo:%p init runtime completed", GET_QINFO_ADDR(pRuntimeEnv));
   return TSDB_CODE_SUCCESS;
@@ -1736,13 +1770,20 @@ static bool needReverseScan(SQuery *pQuery) {
   return false;
 }
 
+/**
+ * The following 4 kinds of query are treated as the tags query
+ * tagprj, tid_tag query, count(tbname), 'abc' (user defined constant value column) query
+ */
 static bool onlyQueryTags(SQuery* pQuery) {
   for(int32_t i = 0; i < pQuery->numOfOutput; ++i) {
     SExprInfo* pExprInfo = &pQuery->pSelectExpr[i];
 
     int32_t functionId = pExprInfo->base.functionId;
-    if (functionId != TSDB_FUNC_TAGPRJ && functionId != TSDB_FUNC_TID_TAG &&
-        (!(functionId == TSDB_FUNC_COUNT && pExprInfo->base.colInfo.colId == TSDB_TBNAME_COLUMN_INDEX))) {
+
+    if (functionId != TSDB_FUNC_TAGPRJ &&
+        functionId != TSDB_FUNC_TID_TAG &&
+        (!(functionId == TSDB_FUNC_COUNT && pExprInfo->base.colInfo.colId == TSDB_TBNAME_COLUMN_INDEX)) &&
+        (!(functionId == TSDB_FUNC_PRJ && pExprInfo->base.colInfo.flag == TSDB_COL_UDC))) {
       return false;
     }
   }
@@ -1803,7 +1844,7 @@ bool colIdCheck(SQuery *pQuery) {
       return false;
     }
   }
-  
+
   return true;
 }
 
@@ -1859,16 +1900,12 @@ static void changeExecuteScanOrder(SQInfo *pQInfo, bool stableQuery) {
   // descending order query for last_row query
   if (isFirstLastRowQuery(pQuery)) {
     qDebug("QInfo:%p scan order changed for last_row query, old:%d, new:%d", GET_QINFO_ADDR(pQuery),
-           pQuery->order.order, TSDB_ORDER_DESC);
-
-    pQuery->order.order = TSDB_ORDER_DESC;
-
-    int64_t skey = MIN(pQuery->window.skey, pQuery->window.ekey);
-    int64_t ekey = MAX(pQuery->window.skey, pQuery->window.ekey);
-
-    pQuery->window.skey = ekey;
-    pQuery->window.ekey = skey;
+           pQuery->order.order, TSDB_ORDER_ASC);
 
+    pQuery->order.order = TSDB_ORDER_ASC;
+    if (pQuery->window.skey > pQuery->window.ekey) {
+      SWAP(pQuery->window.skey, pQuery->window.ekey, TSKEY);
+    }
     return;
   }
 
@@ -1963,7 +2000,7 @@ static void getIntermediateBufInfo(SQueryRuntimeEnv* pRuntimeEnv, int32_t* ps, i
   }
 
   pRuntimeEnv->numOfRowsPerPage = ((*ps) - sizeof(tFilePage)) / (*rowsize);
-
+  assert(pRuntimeEnv->numOfRowsPerPage <= MAX_ROWS_PER_RESBUF_PAGE);
 }
 
 #define IS_PREFILTER_TYPE(_t) ((_t) != TSDB_DATA_TYPE_BINARY && (_t) != TSDB_DATA_TYPE_NCHAR)
@@ -2117,21 +2154,21 @@ int32_t loadDataBlockOnDemand(SQueryRuntimeEnv *pRuntimeEnv, void* pQueryHandle,
     if (tsdbRetrieveDataBlockStatisInfo(pQueryHandle, pStatis) != TSDB_CODE_SUCCESS) {
       //        return DISK_DATA_LOAD_FAILED;
     }
-  
+
     pRuntimeEnv->summary.loadBlockStatis += 1;
-  
+
     if (*pStatis == NULL) { // data block statistics does not exist, load data block
       *pDataBlock = tsdbRetrieveDataBlock(pQueryHandle, NULL);
       pRuntimeEnv->summary.totalCheckedRows += pBlockInfo->rows;
     }
   } else {
     assert(status == BLK_DATA_ALL_NEEDED);
-  
+
     // load the data block statistics to perform further filter
     pRuntimeEnv->summary.loadBlockStatis += 1;
     if (tsdbRetrieveDataBlockStatisInfo(pQueryHandle, pStatis) != TSDB_CODE_SUCCESS) {
     }
-    
+
     if (!needToLoadDataBlock(pRuntimeEnv, *pStatis, pRuntimeEnv->pCtx, pBlockInfo->rows)) {
       // current block has been discard due to filter applied
       pRuntimeEnv->summary.discardBlocks += 1;
@@ -2139,7 +2176,7 @@ int32_t loadDataBlockOnDemand(SQueryRuntimeEnv *pRuntimeEnv, void* pQueryHandle,
           pBlockInfo->window.skey, pBlockInfo->window.ekey, pBlockInfo->rows);
       return BLK_DATA_DISCARD;
     }
-  
+
     pRuntimeEnv->summary.totalCheckedRows += pBlockInfo->rows;
     pRuntimeEnv->summary.loadBlocks += 1;
     *pDataBlock = tsdbRetrieveDataBlock(pQueryHandle, NULL);
@@ -2224,7 +2261,7 @@ static void ensureOutputBufferSimple(SQueryRuntimeEnv* pRuntimeEnv, int32_t capa
 
     char *tmp = realloc(pQuery->sdata[i], bytes * capacity + sizeof(tFilePage));
     if (tmp == NULL) {  // todo handle the oom
-      assert(0);
+      longjmp(pRuntimeEnv->env, TSDB_CODE_QRY_OUT_OF_MEMORY);
     } else {
       pQuery->sdata[i] = (tFilePage *)tmp;
     }
@@ -2244,18 +2281,18 @@ static void ensureOutputBuffer(SQueryRuntimeEnv* pRuntimeEnv, SDataBlockInfo* pB
   SQuery* pQuery = pRuntimeEnv->pQuery;
   if (!QUERY_IS_INTERVAL_QUERY(pQuery) && !pRuntimeEnv->groupbyNormalCol && !isFixedOutputQuery(pRuntimeEnv) && !isTSCompQuery(pQuery)) {
     SResultRec *pRec = &pQuery->rec;
-    
+
     if (pQuery->rec.capacity - pQuery->rec.rows < pBlockInfo->rows) {
       int32_t remain = (int32_t)(pRec->capacity - pRec->rows);
       int32_t newSize = (int32_t)(pRec->capacity + (pBlockInfo->rows - remain));
-      
+
       for (int32_t i = 0; i < pQuery->numOfOutput; ++i) {
         int32_t bytes = pQuery->pSelectExpr[i].bytes;
         assert(bytes > 0 && newSize > 0);
 
         char *tmp = realloc(pQuery->sdata[i], bytes * newSize + sizeof(tFilePage));
         if (tmp == NULL) {  // todo handle the oom
-          assert(0);
+          longjmp(pRuntimeEnv->env, TSDB_CODE_QRY_OUT_OF_MEMORY);
         } else {
           memset(tmp + sizeof(tFilePage) + bytes * pRec->rows, 0, (size_t)((newSize - pRec->rows) * bytes));
           pQuery->sdata[i] = (tFilePage *)tmp;
@@ -2272,7 +2309,7 @@ static void ensureOutputBuffer(SQueryRuntimeEnv* pRuntimeEnv, SDataBlockInfo* pB
       
       qDebug("QInfo:%p realloc output buffer, new size: %d rows, old:%" PRId64 ", remain:%" PRId64, GET_QINFO_ADDR(pRuntimeEnv),
              newSize, pRec->capacity, newSize - pRec->rows);
-      
+
       pRec->capacity = newSize;
     }
   }
@@ -2382,7 +2419,7 @@ static void doSetTagValueInParam(void *tsdb, void* pTable, int32_t tagColId, tVa
   if (tagColId == TSDB_TBNAME_COLUMN_INDEX) {
     char* val = tsdbGetTableName(pTable);
     assert(val != NULL);
-    
+
     tVariantCreateFromBinary(tag, varDataVal(val), varDataLen(val), TSDB_DATA_TYPE_BINARY);
   } else {
     char* val = tsdbGetTableTagVal(pTable, tagColId, type, bytes);
@@ -2390,7 +2427,7 @@ static void doSetTagValueInParam(void *tsdb, void* pTable, int32_t tagColId, tVa
       tag->nType = TSDB_DATA_TYPE_NULL;
       return;
     }
-    
+
     if (type == TSDB_DATA_TYPE_BINARY || type == TSDB_DATA_TYPE_NCHAR) {
       if (isNull(val, type)) {
         tag->nType = TSDB_DATA_TYPE_NULL;
@@ -2437,7 +2474,7 @@ void setTagVal(SQueryRuntimeEnv *pRuntimeEnv, void *pTable, void *tsdb) {
     // set tag value, by which the results are aggregated.
     for (int32_t idx = 0; idx < pQuery->numOfOutput; ++idx) {
       SExprInfo* pLocalExprInfo = &pQuery->pSelectExpr[idx];
-  
+
       // ts_comp column required the tag value for join filter
       if (!TSDB_COL_IS_TAG(pLocalExprInfo->base.colInfo.flag)) {
         continue;
@@ -2487,14 +2524,14 @@ static void doMerge(SQueryRuntimeEnv *pRuntimeEnv, int64_t timestamp, SWindowRes
     // in case of tag column, the tag information should be extracted from input buffer
     if (functionId == TSDB_FUNC_TAG_DUMMY || functionId == TSDB_FUNC_TAG) {
       tVariantDestroy(&pCtx[i].tag);
-  
+
       int32_t type = pCtx[i].outputType;
       if (type == TSDB_DATA_TYPE_BINARY || type == TSDB_DATA_TYPE_NCHAR) {
         tVariantCreateFromBinary(&pCtx[i].tag, varDataVal(pCtx[i].aInputElemBuf), varDataLen(pCtx[i].aInputElemBuf), type);
       } else {
         tVariantCreateFromBinary(&pCtx[i].tag, pCtx[i].aInputElemBuf, pCtx[i].inputBytes, pCtx[i].inputType);
       }
-      
+
     }
   }
 
@@ -2584,7 +2621,7 @@ void UNUSED_FUNC displayInterResult(tFilePage **pdata, SQueryRuntimeEnv* pRuntim
 
   for (int32_t j = 0; j < numOfRows; ++j) {
     for (int32_t i = 0; i < numOfCols; ++i) {
-      
+
       switch (pQuery->pSelectExpr[i].type) {
         case TSDB_DATA_TYPE_BINARY: {
           int32_t type = pQuery->pSelectExpr[i].type;
@@ -2659,7 +2696,7 @@ int32_t tableResultComparFn(const void *pLeft, const void *pRight, void *param)
 }
 
 int32_t mergeIntoGroupResult(SQInfo *pQInfo) {
-  int64_t st = taosGetTimestampMs();
+  int64_t st = taosGetTimestampUs();
   int32_t ret = TSDB_CODE_SUCCESS;
 
   int32_t numOfGroups = (int32_t)(GET_NUM_OF_TABLEGROUP(pQInfo));
@@ -2678,23 +2715,30 @@ int32_t mergeIntoGroupResult(SQInfo *pQInfo) {
       break;
     }
 
-    assert(pQInfo->numOfGroupResultPages == 0);
+    assert(pQInfo->groupResInfo.numOfDataPages == 0);
     qDebug("QInfo:%p no result in group %d, continue", pQInfo, pQInfo->groupIndex - 1);
   }
 
-  if (pQInfo->groupIndex == numOfGroups && pQInfo->offset == pQInfo->numOfGroupResultPages) {
+  SGroupResInfo* info = &pQInfo->groupResInfo;
+  if (pQInfo->groupIndex == numOfGroups && info->pos.pageId == info->numOfDataPages) {
     SET_STABLE_QUERY_OVER(pQInfo);
   }
 
-  qDebug("QInfo:%p merge res data into group, index:%d, total group:%d, elapsed time:%" PRId64 "ms", pQInfo,
-         pQInfo->groupIndex - 1, numOfGroups, taosGetTimestampMs() - st);
+  int64_t elapsedTime = taosGetTimestampUs() - st;
+  qDebug("QInfo:%p merge res data into group, index:%d, total group:%d, elapsed time:%" PRId64 "us", pQInfo,
+         pQInfo->groupIndex - 1, numOfGroups, elapsedTime);
 
+  pQInfo->runtimeEnv.summary.firstStageMergeTime += elapsedTime;
   return TSDB_CODE_SUCCESS;
 }
 
 void copyResToQueryResultBuf(SQInfo *pQInfo, SQuery *pQuery) {
-  if (pQInfo->offset == pQInfo->numOfGroupResultPages) {
-    pQInfo->numOfGroupResultPages = 0;
+  SGroupResInfo* pGroupResInfo = &pQInfo->groupResInfo;
+
+  // all results have been return to client, try next group
+  if (pGroupResInfo->pos.pageId == pGroupResInfo->numOfDataPages) {
+    pGroupResInfo->numOfDataPages = 0;
+    pGroupResInfo->pos.rowId = 0;
 
     // current results of group has been sent to client, try next group
     if (mergeIntoGroupResult(pQInfo) != TSDB_CODE_SUCCESS) {
@@ -2703,7 +2747,7 @@ void copyResToQueryResultBuf(SQInfo *pQInfo, SQuery *pQuery) {
 
     // check if all results has been sent to client
     int32_t numOfGroup = (int32_t)(GET_NUM_OF_TABLEGROUP(pQInfo));
-    if (pQInfo->numOfGroupResultPages == 0 && pQInfo->groupIndex == numOfGroup) {
+    if (pGroupResInfo->numOfDataPages == 0 && pQInfo->groupIndex == numOfGroup) {
       SET_STABLE_QUERY_OVER(pQInfo);
       return;
     }
@@ -2712,29 +2756,50 @@ void copyResToQueryResultBuf(SQInfo *pQInfo, SQuery *pQuery) {
   SQueryRuntimeEnv *   pRuntimeEnv = &pQInfo->runtimeEnv;
   SDiskbasedResultBuf *pResultBuf = pRuntimeEnv->pResultBuf;
 
-  int32_t id = getGroupResultId(pQInfo->groupIndex - 1);
-  SIDList list = getDataBufPagesIdList(pResultBuf, pQInfo->offset + id);
-
-  int32_t size = (int32_t)(taosArrayGetSize(list));
+  int32_t id = pQInfo->groupResInfo.groupId;
+  SIDList list = getDataBufPagesIdList(pResultBuf, id);
 
   int32_t offset = 0;
-  for (int32_t j = 0; j < size; ++j) {
+  int32_t numOfCopiedRows = 0;
+
+  size_t size = taosArrayGetSize(list);
+  assert(size == pGroupResInfo->numOfDataPages);
+
+  bool done = false;
+  for (int32_t j = pGroupResInfo->pos.pageId; j < size; ++j) {
     SPageInfo* pi = *(SPageInfo**) taosArrayGet(list, j);
-    tFilePage *pData = getResBufPage(pResultBuf, pi->pageId);
+    tFilePage* pData = getResBufPage(pResultBuf, pi->pageId);
+
+    assert(pData->num > 0 && pData->num <= pRuntimeEnv->numOfRowsPerPage && pGroupResInfo->pos.rowId < pData->num);
+    int32_t numOfRes = (int32_t)(pData->num - pGroupResInfo->pos.rowId);
+
+    if (numOfRes > pQuery->rec.capacity - offset) {
+      numOfCopiedRows = (int32_t)(pQuery->rec.capacity - offset);
+      pGroupResInfo->pos.rowId += numOfCopiedRows;
+      done = true;
+    } else {
+      numOfCopiedRows = (int32_t)pData->num;
+
+      pGroupResInfo->pos.pageId += 1;
+      pGroupResInfo->pos.rowId = 0;
+    }
 
     for (int32_t i = 0; i < pQuery->numOfOutput; ++i) {
       int32_t bytes = pRuntimeEnv->pCtx[i].outputBytes;
       char *  pDest = pQuery->sdata[i]->data;
-      memcpy(pDest + offset * bytes, pData->data + pRuntimeEnv->offset[i] * pData->num, (size_t)(bytes * pData->num));
+
+      memcpy(pDest + offset * bytes, pData->data + pRuntimeEnv->offset[i] * pRuntimeEnv->numOfRowsPerPage,
+          (size_t)bytes * numOfCopiedRows);
     }
 
-    offset += (int32_t)pData->num;
+    offset += numOfCopiedRows;
+    if (done) {
+      break;
+    }
   }
 
   assert(pQuery->rec.rows == 0);
-
   pQuery->rec.rows += offset;
-  pQInfo->offset += 1;
 }
 
 int64_t getNumOfResultWindowRes(SQuery *pQuery, SWindowResult *pWindowRes) {
@@ -2767,7 +2832,7 @@ int32_t mergeIntoGroupResultImpl(SQInfo *pQInfo, SArray *pGroup) {
   size_t size = taosArrayGetSize(pGroup);
   tFilePage **buffer = pQuery->sdata;
 
-  int32_t*   posList = calloc(size, sizeof(int32_t));
+  int32_t *posList = calloc(size, sizeof(int32_t));
   STableQueryInfo **pTableList = malloc(POINTER_BYTES * size);
 
   if (pTableList == NULL || posList == NULL) {
@@ -2780,23 +2845,38 @@ int32_t mergeIntoGroupResultImpl(SQInfo *pQInfo, SArray *pGroup) {
 
   // todo opt for the case of one table per group
   int32_t numOfTables = 0;
+  SIDList pageList = NULL;
+  int32_t tid = -1;
+
   for (int32_t i = 0; i < size; ++i) {
     STableQueryInfo *item = taosArrayGetP(pGroup, i);
 
     SIDList list = getDataBufPagesIdList(pRuntimeEnv->pResultBuf, TSDB_TABLEID(item->pTable)->tid);
+    pageList = list;
+    tid = TSDB_TABLEID(item->pTable)->tid;
+
     if (taosArrayGetSize(list) > 0 && item->windowResInfo.size > 0) {
-      pTableList[numOfTables] = item;
-      numOfTables += 1;
+      pTableList[numOfTables++] = item;
     }
   }
 
+  // there is no data in current group
   if (numOfTables == 0) {
     taosTFree(posList);
     taosTFree(pTableList);
-
-    assert(pQInfo->numOfGroupResultPages == 0);
     return 0;
   } else if (numOfTables == 1) { // no need to merge results since only one table in each group
+    taosTFree(posList);
+    taosTFree(pTableList);
+
+    SGroupResInfo* pGroupResInfo = &pQInfo->groupResInfo;
+
+    pGroupResInfo->numOfDataPages = (int32_t)taosArrayGetSize(pageList);
+    pGroupResInfo->groupId = tid;
+    pGroupResInfo->pos.pageId = 0;
+    pGroupResInfo->pos.rowId = 0;
+
+    return pGroupResInfo->numOfDataPages;
   }
 
   SCompSupporter cs = {pTableList, posList, pQInfo};
@@ -2810,9 +2890,15 @@ int32_t mergeIntoGroupResultImpl(SQInfo *pQInfo, SArray *pGroup) {
   }
 
   char* buf = calloc(1, pRuntimeEnv->interBufSize);
+  if (buf == NULL) {
+    longjmp(pRuntimeEnv->env, TSDB_CODE_QRY_OUT_OF_MEMORY);
+  }
+
   setWindowResultInfo(pResultInfo, pQuery, pRuntimeEnv->stableQuery, buf);
   resetMergeResultBuf(pQuery, pRuntimeEnv->pCtx, pResultInfo);
 
+  pQInfo->groupResInfo.groupId = getGroupResultId(pQInfo->groupIndex);
+
   // todo add windowRes iterator
   int64_t lastTimestamp = -1;
   int64_t startt = taosGetTimestampMs();
@@ -2820,6 +2906,13 @@ int32_t mergeIntoGroupResultImpl(SQInfo *pQInfo, SArray *pGroup) {
   while (1) {
     if (IS_QUERY_KILLED(pQInfo)) {
       qDebug("QInfo:%p it is already killed, abort", pQInfo);
+
+      taosTFree(pTableList);
+      taosTFree(posList);
+      taosTFree(pTree);
+      taosTFree(pResultInfo);
+      taosTFree(buf);
+
       longjmp(pRuntimeEnv->env, TSDB_CODE_TSC_QUERY_CANCELLED);
     }
 
@@ -2832,7 +2925,7 @@ int32_t mergeIntoGroupResultImpl(SQInfo *pQInfo, SArray *pGroup) {
     char *b = getPosInResultPage(pRuntimeEnv, PRIMARYKEY_TIMESTAMP_COL_INDEX, pWindowRes, page);
     TSKEY ts = GET_INT64_VAL(b);
 
-    assert(ts == pWindowRes->window.skey);
+    assert(ts == pWindowRes->skey);
     int64_t num = getNumOfResultWindowRes(pQuery, pWindowRes);
     if (num <= 0) {
       cs.position[pos] += 1;
@@ -2850,7 +2943,7 @@ int32_t mergeIntoGroupResultImpl(SQInfo *pQInfo, SArray *pGroup) {
         doMerge(pRuntimeEnv, ts, pWindowRes, true);
       } else {  // copy data to disk buffer
         if (buffer[0]->num == pQuery->rec.capacity) {
-          if (flushFromResultBuf(pQInfo) != TSDB_CODE_SUCCESS) {
+          if (flushFromResultBuf(pRuntimeEnv, &pQInfo->groupResInfo) != TSDB_CODE_SUCCESS) {
             return -1;
           }
 
@@ -2887,7 +2980,7 @@ int32_t mergeIntoGroupResultImpl(SQInfo *pQInfo, SArray *pGroup) {
   }
 
   if (buffer[0]->num != 0) {  // there are data in buffer
-    if (flushFromResultBuf(pQInfo) != TSDB_CODE_SUCCESS) {
+    if (flushFromResultBuf(pRuntimeEnv, &pQInfo->groupResInfo) != TSDB_CODE_SUCCESS) {
       qError("QInfo:%p failed to flush data into temp file, abort query", pQInfo);
 
       taosTFree(pTree);
@@ -2911,16 +3004,14 @@ int32_t mergeIntoGroupResultImpl(SQInfo *pQInfo, SArray *pGroup) {
   taosTFree(posList);
   taosTFree(pTree);
 
-  pQInfo->offset = 0;
-
   taosTFree(pResultInfo);
   taosTFree(buf);
-  return pQInfo->numOfGroupResultPages;
+
+  return pQInfo->groupResInfo.numOfDataPages;
 }
 
-int32_t flushFromResultBuf(SQInfo *pQInfo) {
-  SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
-  SQuery *          pQuery = pRuntimeEnv->pQuery;
+int32_t flushFromResultBuf(SQueryRuntimeEnv* pRuntimeEnv, SGroupResInfo* pGroupResInfo) {
+  SQuery *pQuery = pRuntimeEnv->pQuery;
 
   SDiskbasedResultBuf *pResultBuf = pRuntimeEnv->pResultBuf;
 
@@ -2928,32 +3019,32 @@ int32_t flushFromResultBuf(SQInfo *pQInfo) {
   int32_t pageId = -1;
   int32_t capacity = pResultBuf->numOfRowsPerPage;
 
-  int32_t remain = (int32_t)pQuery->sdata[0]->num;
+  int32_t remain = (int32_t) pQuery->sdata[0]->num;
   int32_t offset = 0;
 
   while (remain > 0) {
-    int32_t r = remain;
-    if (r > capacity) {
-      r = capacity;
-    }
+    int32_t rows = (remain > capacity)? capacity:remain;
+    assert(rows > 0);
 
-    int32_t    id = getGroupResultId(pQInfo->groupIndex) + pQInfo->numOfGroupResultPages;
-    tFilePage *buf = getNewDataBuf(pResultBuf, id, &pageId);
+    // get the output buffer page
+    tFilePage *buf = getNewDataBuf(pResultBuf, pGroupResInfo->groupId, &pageId);
+    buf->num = rows;
 
-    // pagewise copy to dest buffer
+    // pagewisely copy to dest buffer
     for (int32_t i = 0; i < pQuery->numOfOutput; ++i) {
       int32_t bytes = pRuntimeEnv->pCtx[i].outputBytes;
-      buf->num = r;
 
-      memcpy(buf->data + pRuntimeEnv->offset[i] * buf->num, ((char *)pQuery->sdata[i]->data) + offset * bytes,
-            (size_t)(buf->num * bytes));
+      char* output = buf->data + pRuntimeEnv->offset[i] * pRuntimeEnv->numOfRowsPerPage;
+      char* src = ((char *) pQuery->sdata[i]->data) + offset * bytes;
+      memcpy(output, src, (size_t)(buf->num * bytes));
     }
 
-    offset += r;
-    remain -= r;
+    offset += rows;
+    remain -= rows;
+
+    pGroupResInfo->numOfDataPages += 1;
   }
 
-  pQInfo->numOfGroupResultPages += 1;
   return TSDB_CODE_SUCCESS;
 }
 
@@ -2972,10 +3063,10 @@ static void updateTableQueryInfoForReverseScan(SQuery *pQuery, STableQueryInfo *
   if (pTableQueryInfo == NULL) {
     return;
   }
-  
+
   // order has changed already
   int32_t step = GET_FORWARD_DIRECTION_FACTOR(pQuery->order.order);
-  
+
   // TODO validate the assertion
 //  if (!QUERY_IS_ASC_QUERY(pQuery)) {
 //    assert(pTableQueryInfo->win.ekey >= pTableQueryInfo->lastKey + step);
@@ -2991,7 +3082,7 @@ static void updateTableQueryInfoForReverseScan(SQuery *pQuery, STableQueryInfo *
 
   SWAP(pTableQueryInfo->win.skey, pTableQueryInfo->win.ekey, TSKEY);
   pTableQueryInfo->lastKey = pTableQueryInfo->win.skey;
-  
+
   SWITCH_ORDER(pTableQueryInfo->cur.order);
   pTableQueryInfo->cur.vgroupIndex = -1;
 
@@ -3001,10 +3092,10 @@ static void updateTableQueryInfoForReverseScan(SQuery *pQuery, STableQueryInfo *
 
 static void disableFuncInReverseScanImpl(SQInfo* pQInfo, SWindowResInfo *pWindowResInfo, int32_t order) {
   SQuery* pQuery = pQInfo->runtimeEnv.pQuery;
-  
+
   for (int32_t i = 0; i < pWindowResInfo->size; ++i) {
-    SWindowStatus *pStatus = getTimeWindowResStatus(pWindowResInfo, i);
-    if (!pStatus->closed) {
+    bool closed = getTimeWindowResStatus(pWindowResInfo, i);
+    if (!closed) {
       continue;
     }
 
@@ -3065,7 +3156,8 @@ static void setupQueryRangeForReverseScan(SQInfo* pQInfo) {
       STableQueryInfo *pCheckInfo = taosArrayGetP(group, j);
       updateTableQueryInfoForReverseScan(pQuery, pCheckInfo);
 
-      // update the last key in tableKeyInfo list
+      // update the last key in tableKeyInfo list, the tableKeyInfo is used to build the tsdbQueryHandle and decide
+      // the start check timestamp of tsdbQueryHandle
       STableKeyInfo *pTableKeyInfo = taosArrayGet(tableKeyGroup, j);
       pTableKeyInfo->lastKey = pCheckInfo->lastKey;
 
@@ -3178,7 +3270,7 @@ void skipResults(SQueryRuntimeEnv *pRuntimeEnv) {
   if (pQuery->rec.rows <= pQuery->limit.offset) {
     qDebug("QInfo:%p skip rows:%" PRId64 ", new offset:%" PRIu64, GET_QINFO_ADDR(pRuntimeEnv), pQuery->rec.rows,
         pQuery->limit.offset - pQuery->rec.rows);
-    
+
     pQuery->limit.offset -= pQuery->rec.rows;
     pQuery->rec.rows = 0;
 
@@ -3190,10 +3282,10 @@ void skipResults(SQueryRuntimeEnv *pRuntimeEnv) {
     int64_t numOfSkip = pQuery->limit.offset;
     pQuery->rec.rows -= numOfSkip;
     pQuery->limit.offset = 0;
-  
+
     qDebug("QInfo:%p skip row:%"PRId64", new offset:%d, numOfRows remain:%" PRIu64, GET_QINFO_ADDR(pRuntimeEnv), numOfSkip,
            0, pQuery->rec.rows);
-    
+
     for (int32_t i = 0; i < pQuery->numOfOutput; ++i) {
       int32_t functionId = pQuery->pSelectExpr[i].base.functionId;
       int32_t bytes = pRuntimeEnv->pCtx[i].outputBytes;
@@ -3230,7 +3322,7 @@ bool needScanDataBlocksAgain(SQueryRuntimeEnv *pRuntimeEnv) {
 
     for (int32_t i = 0; i < pWindowResInfo->size; ++i) {
       SWindowResult *pResult = getWindowResult(pWindowResInfo, i);
-      if (!pResult->status.closed) {
+      if (!pResult->closed) {
         continue;
       }
 
@@ -3268,10 +3360,10 @@ bool needScanDataBlocksAgain(SQueryRuntimeEnv *pRuntimeEnv) {
 static SQueryStatusInfo getQueryStatusInfo(SQueryRuntimeEnv *pRuntimeEnv, TSKEY start) {
   SQuery *pQuery = pRuntimeEnv->pQuery;
   STableQueryInfo* pTableQueryInfo = pQuery->current;
-  
+
   assert((start <= pTableQueryInfo->lastKey && QUERY_IS_ASC_QUERY(pQuery)) ||
       (start >= pTableQueryInfo->lastKey && !QUERY_IS_ASC_QUERY(pQuery)));
-  
+
   SQueryStatusInfo info = {
       .status      = pQuery->status,
       .windowIndex = pRuntimeEnv->windowResInfo.curIndex,
@@ -3293,7 +3385,8 @@ static void setEnvBeforeReverseScan(SQueryRuntimeEnv *pRuntimeEnv, SQueryStatusI
   pStatus->cur = tsBufGetCursor(pRuntimeEnv->pTSBuf);  // save the cursor
   if (pRuntimeEnv->pTSBuf) {
     SWITCH_ORDER(pRuntimeEnv->pTSBuf->cur.order);
-    tsBufNextPos(pRuntimeEnv->pTSBuf);
+    bool ret = tsBufNextPos(pRuntimeEnv->pTSBuf);
+    assert(ret);
   }
 
   // reverse order time range
@@ -3351,7 +3444,7 @@ static void clearEnvAfterReverseScan(SQueryRuntimeEnv *pRuntimeEnv, SQueryStatus
   // update the pQuery->window.skey and pQuery->window.ekey to limit the scan scope of sliding query during reverse scan
   pTableQueryInfo->lastKey = pStatus->lastKey;
   pQuery->status = pStatus->status;
-  
+
   pTableQueryInfo->win = pStatus->w;
   pQuery->window = pTableQueryInfo->win;
 }
@@ -3367,7 +3460,7 @@ void scanOneTableDataBlocks(SQueryRuntimeEnv *pRuntimeEnv, TSKEY start) {
   SQInfo *pQInfo = (SQInfo *) GET_QINFO_ADDR(pRuntimeEnv);
   SQuery *pQuery = pRuntimeEnv->pQuery;
   STableQueryInfo *pTableQueryInfo = pQuery->current;
-  
+
   setQueryStatus(pQuery, QUERY_NOT_COMPLETED);
 
   // store the start query position
@@ -3420,7 +3513,7 @@ void scanOneTableDataBlocks(SQueryRuntimeEnv *pRuntimeEnv, TSKEY start) {
     pRuntimeEnv->windowResInfo.curIndex = qstatus.windowIndex;
     setQueryStatus(pQuery, QUERY_NOT_COMPLETED);
     pRuntimeEnv->scanFlag = REPEAT_SCAN;
-    
+
     qDebug("QInfo:%p start to repeat scan data blocks due to query func required, qrange:%"PRId64"-%"PRId64, pQInfo,
         cond.twindow.skey, cond.twindow.ekey);
 
@@ -3525,12 +3618,6 @@ void destroyTableQueryInfo(STableQueryInfo *pTableQueryInfo) {
   cleanupTimeWindowInfo(&pTableQueryInfo->windowResInfo);
 }
 
-#define CHECK_QUERY_TIME_RANGE(_q, _tableInfo)                                              \
-  do {                                                                                      \
-    assert((((_tableInfo)->lastKey >= (_tableInfo)->win.skey) && QUERY_IS_ASC_QUERY(_q)) || \
-           (((_tableInfo)->lastKey <= (_tableInfo)->win.skey) && !QUERY_IS_ASC_QUERY(_q))); \
-  } while (0)
-
 /**
  * set output buffer for different group
  * @param pRuntimeEnv
@@ -3644,9 +3731,8 @@ int32_t setAdditionalInfo(SQInfo *pQInfo, void* pTable, STableQueryInfo *pTableQ
   // both the master and supplement scan needs to set the correct ts comp start position
   if (pRuntimeEnv->pTSBuf != NULL) {
     if (pTableQueryInfo->cur.vgroupIndex == -1) {
-      pTableQueryInfo->tag = pRuntimeEnv->pCtx[0].tag.i64Key;
-
-      tsBufGetElemStartPos(pRuntimeEnv->pTSBuf, 0, pTableQueryInfo->tag);
+      tVariantAssign(&pTableQueryInfo->tag, &pRuntimeEnv->pCtx[0].tag);
+      tsBufGetElemStartPos(pRuntimeEnv->pTSBuf, 0, &pTableQueryInfo->tag);
 
       // keep the cursor info of current meter
       pTableQueryInfo->cur = pRuntimeEnv->pTSBuf->cur;
@@ -3671,7 +3757,7 @@ void setIntervalQueryRange(SQInfo *pQInfo, TSKEY key) {
   SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
   SQuery *          pQuery = pRuntimeEnv->pQuery;
   STableQueryInfo *pTableQueryInfo = pQuery->current;
-  
+
   if (pTableQueryInfo->queryRangeSet) {
     pTableQueryInfo->lastKey = key;
   } else {
@@ -3702,7 +3788,7 @@ void setIntervalQueryRange(SQInfo *pQInfo, TSKEY key) {
       if (!QUERY_IS_ASC_QUERY(pQuery)) {
         assert(win.ekey == pQuery->window.ekey);
       }
-      
+
       pWindowResInfo->prevSKey = w.skey;
     }
 
@@ -3728,7 +3814,7 @@ bool needPrimaryTimestampCol(SQuery *pQuery, SDataBlockInfo *pDataBlockInfo) {
    */
   STimeWindow *w = &pDataBlockInfo->window;
   STableQueryInfo* pTableQueryInfo = pQuery->current;
-  
+
   bool loadPrimaryTS = (pTableQueryInfo->lastKey >= w->skey && pTableQueryInfo->lastKey <= w->ekey) ||
                        (pQuery->window.ekey >= w->skey && pQuery->window.ekey <= w->ekey) || requireTimestamp(pQuery);
 
@@ -3755,27 +3841,27 @@ static int32_t doCopyToSData(SQInfo *pQInfo, SWindowResInfo *pResultInfo, int32_
     step = -1;
   }
 
+  SGroupResInfo* pGroupResInfo = &pQInfo->groupResInfo;
+
   for (int32_t i = startIdx; (i < totalSet) && (i >= 0); i += step) {
     if (result[i].numOfRows == 0) {
-      pQInfo->offset = 0;
       pQInfo->groupIndex += 1;
+      pGroupResInfo->pos.rowId = 0;
       continue;
     }
 
-    assert(pQInfo->offset <= 1);
-
-    int32_t numOfRowsToCopy = result[i].numOfRows - pQInfo->offset;
-    int32_t oldOffset = pQInfo->offset;
+    int32_t numOfRowsToCopy = result[i].numOfRows - pGroupResInfo->pos.rowId;
+    int32_t oldOffset = pGroupResInfo->pos.rowId;
 
     /*
-     * current output space is not enough to keep all the result data of this group, only copy partial results
-     * to SQuery object's result buffer
+     * current output space is not enough to accommodate all data of this page, only partial results
+     * will be copied to SQuery object's result buffer
      */
     if (numOfRowsToCopy > pQuery->rec.capacity - numOfResult) {
-      numOfRowsToCopy = (int32_t)pQuery->rec.capacity - numOfResult;
-      pQInfo->offset += numOfRowsToCopy;
+      numOfRowsToCopy = (int32_t) pQuery->rec.capacity - numOfResult;
+      pGroupResInfo->pos.rowId += numOfRowsToCopy;
     } else {
-      pQInfo->offset = 0;
+      pGroupResInfo->pos.rowId = 0;
       pQInfo->groupIndex += 1;
     }
 
@@ -3840,7 +3926,7 @@ static void updateWindowResNumOfRes(SQueryRuntimeEnv *pRuntimeEnv) {
         continue;
       }
 
-      pResult->numOfRows = MAX(pResult->numOfRows, pResult->resultInfo[j].numOfRes);
+      pResult->numOfRows = (uint16_t)(MAX(pResult->numOfRows, pResult->resultInfo[j].numOfRes));
     }
   }
 }
@@ -3849,7 +3935,7 @@ static void stableApplyFunctionsOnBlock(SQueryRuntimeEnv *pRuntimeEnv, SDataBloc
     SArray *pDataBlock, __block_search_fn_t searchFn) {
   SQuery *         pQuery = pRuntimeEnv->pQuery;
   STableQueryInfo* pTableQueryInfo = pQuery->current;
-  
+
   SWindowResInfo * pWindowResInfo = &pTableQueryInfo->windowResInfo;
   pQuery->pos = QUERY_IS_ASC_QUERY(pQuery)? 0 : pDataBlockInfo->rows - 1;
 
@@ -3941,10 +4027,10 @@ int32_t doFillGapsInResults(SQueryRuntimeEnv* pRuntimeEnv, tFilePage **pDst, int
   SQInfo* pQInfo = GET_QINFO_ADDR(pRuntimeEnv);
   SQuery *pQuery = pRuntimeEnv->pQuery;
   SFillInfo* pFillInfo = pRuntimeEnv->pFillInfo;
-  
+
   while (1) {
     int32_t ret = (int32_t)taosGenerateDataBlock(pFillInfo, (tFilePage**)pQuery->sdata, (int32_t)pQuery->rec.capacity);
-    
+
     // todo apply limit output function
     /* reached the start position of according to offset value, return immediately */
     if (pQuery->limit.offset == 0) {
@@ -3955,7 +4041,7 @@ int32_t doFillGapsInResults(SQueryRuntimeEnv* pRuntimeEnv, tFilePage **pDst, int
     if (pQuery->limit.offset < ret) {
       qDebug("QInfo:%p initial numOfRows:%d, generate filled result:%d rows, offset:%" PRId64 ". Discard due to offset, remain:%" PRId64 ", new offset:%d",
              pQInfo, pFillInfo->numOfRows, ret, pQuery->limit.offset, ret - pQuery->limit.offset, 0);
-      
+
       ret -= (int32_t)pQuery->limit.offset;
       // todo !!!!there exactly number of interpo is not valid.
       // todo refactor move to the beginning of buffer
@@ -3963,14 +4049,14 @@ int32_t doFillGapsInResults(SQueryRuntimeEnv* pRuntimeEnv, tFilePage **pDst, int
         memmove(pDst[i]->data, pDst[i]->data + pQuery->pSelectExpr[i].bytes * pQuery->limit.offset,
                 ret * pQuery->pSelectExpr[i].bytes);
       }
-      
+
       pQuery->limit.offset = 0;
       return ret;
     } else {
       qDebug("QInfo:%p initial numOfRows:%d, generate filled result:%d rows, offset:%" PRId64 ". Discard due to offset, "
              "remain:%d, new offset:%" PRId64, pQInfo, pFillInfo->numOfRows, ret, pQuery->limit.offset, 0,
           pQuery->limit.offset - ret);
-      
+
       pQuery->limit.offset -= ret;
       pQuery->rec.rows = 0;
       ret = 0;
@@ -3986,18 +4072,22 @@ static void queryCostStatis(SQInfo *pQInfo) {
   SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
   SQueryCostInfo *pSummary = &pRuntimeEnv->summary;
 
-  qDebug("QInfo:%p :cost summary: elapsed time:%"PRId64" us, total blocks:%d, load block statis:%d,"
-         " load data block:%d, total rows:%"PRId64 ", check rows:%"PRId64,
-         pQInfo, pSummary->elapsedTime, pSummary->totalBlocks, pSummary->loadBlockStatis,
+  // add the merge time
+  pSummary->elapsedTime += pSummary->firstStageMergeTime;
+
+  qDebug("QInfo:%p :cost summary: elapsed time:%"PRId64" us, first merge:%"PRId64" us, total blocks:%d, "
+         "load block statis:%d, load data block:%d, total rows:%"PRId64 ", check rows:%"PRId64,
+         pQInfo, pSummary->elapsedTime, pSummary->firstStageMergeTime, pSummary->totalBlocks, pSummary->loadBlockStatis,
          pSummary->loadBlocks, pSummary->totalRows, pSummary->totalCheckedRows);
 
-  qDebug("QInfo:%p :cost summary: internal size:%"PRId64, pQInfo, pSummary->internalSupSize);
+  qDebug("QInfo:%p :cost summary: internal size:%"PRId64"B, numOfWin:%"PRId64, pQInfo, pSummary->internalSupSize,
+      pSummary->numOfTimeWindows);
 }
 
 static void updateOffsetVal(SQueryRuntimeEnv *pRuntimeEnv, SDataBlockInfo *pBlockInfo) {
   SQuery *pQuery = pRuntimeEnv->pQuery;
   STableQueryInfo* pTableQueryInfo = pQuery->current;
-  
+
   int32_t step = GET_FORWARD_DIRECTION_FACTOR(pQuery->order.order);
 
   if (pQuery->limit.offset == pBlockInfo->rows) {  // current block will ignore completed
@@ -4087,7 +4177,7 @@ static bool skipTimeInterval(SQueryRuntimeEnv *pRuntimeEnv, TSKEY* start) {
   assert(pRuntimeEnv->windowResInfo.prevSKey == TSKEY_INITIAL_VAL);
 
   STimeWindow w = TSWINDOW_INITIALIZER;
-  
+
   SWindowResInfo *pWindowResInfo = &pRuntimeEnv->windowResInfo;
   STableQueryInfo *pTableQueryInfo = pQuery->current;
 
@@ -4136,21 +4226,21 @@ static bool skipTimeInterval(SQueryRuntimeEnv *pRuntimeEnv, TSKEY* start) {
 
           // set the abort info
           pQuery->pos = startPos;
-          
+
           // reset the query start timestamp
           pTableQueryInfo->win.skey = ((TSKEY *)pColInfoData->pData)[startPos];
           pQuery->window.skey = pTableQueryInfo->win.skey;
           *start = pTableQueryInfo->win.skey;
-          
+
           pWindowResInfo->prevSKey = tw.skey;
           int32_t index = pRuntimeEnv->windowResInfo.curIndex;
-          
+
           int32_t numOfRes = tableApplyFunctionsOnBlock(pRuntimeEnv, &blockInfo, NULL, binarySearchForKey, pDataBlock);
           pRuntimeEnv->windowResInfo.curIndex = index;  // restore the window index
-          
+
           qDebug("QInfo:%p check data block, brange:%" PRId64 "-%" PRId64 ", numOfRows:%d, numOfRes:%d, lastKey:%"PRId64,
                  GET_QINFO_ADDR(pRuntimeEnv), blockInfo.window.skey, blockInfo.window.ekey, blockInfo.rows, numOfRes, pQuery->current->lastKey);
-          
+
           return true;
         } else { // do nothing
           *start = tw.skey;
@@ -4218,7 +4308,7 @@ static int32_t setupQueryHandle(void* tsdb, SQInfo* pQInfo, bool isSTableQuery)
 
   if (!isSTableQuery
     && (pQInfo->tableqinfoGroupInfo.numOfTables == 1)
-    && (cond.order == TSDB_ORDER_ASC) 
+    && (cond.order == TSDB_ORDER_ASC)
     && (!QUERY_IS_INTERVAL_QUERY(pQuery))
     && (!isGroupbyNormalCol(pQuery->pGroupbyExpr))
     && (!isFixedOutputQuery(pRuntimeEnv))
@@ -4231,6 +4321,22 @@ static int32_t setupQueryHandle(void* tsdb, SQInfo* pQInfo, bool isSTableQuery)
   terrno = TSDB_CODE_SUCCESS;
   if (isFirstLastRowQuery(pQuery)) {
     pRuntimeEnv->pQueryHandle = tsdbQueryLastRow(tsdb, &cond, &pQInfo->tableGroupInfo, pQInfo);
+
+    // update the query time window
+    pQuery->window = cond.twindow;
+
+    size_t numOfGroups = GET_NUM_OF_TABLEGROUP(pQInfo);
+    for(int32_t i = 0; i < numOfGroups; ++i) {
+      SArray *group = GET_TABLEGROUP(pQInfo, i);
+
+      size_t t = taosArrayGetSize(group);
+      for (int32_t j = 0; j < t; ++j) {
+        STableQueryInfo *pCheckInfo = taosArrayGetP(group, j);
+
+        pCheckInfo->win = pQuery->window;
+        pCheckInfo->lastKey = pCheckInfo->win.skey;
+      }
+    }
   } else if (isPointInterpoQuery(pQuery)) {
     pRuntimeEnv->pQueryHandle = tsdbQueryRowsInExternalWindow(tsdb, &cond, &pQInfo->tableGroupInfo, pQInfo);
   } else {
@@ -4243,21 +4349,25 @@ static int32_t setupQueryHandle(void* tsdb, SQInfo* pQInfo, bool isSTableQuery)
 static SFillColInfo* taosCreateFillColInfo(SQuery* pQuery) {
   int32_t numOfCols = pQuery->numOfOutput;
   int32_t offset = 0;
-  
+
   SFillColInfo* pFillCol = calloc(numOfCols, sizeof(SFillColInfo));
+  if (pFillCol == NULL) {
+    return NULL;
+  }
+
   for(int32_t i = 0; i < numOfCols; ++i) {
     SExprInfo* pExprInfo = &pQuery->pSelectExpr[i];
-    
+
     pFillCol[i].col.bytes  = pExprInfo->bytes;
     pFillCol[i].col.type   = (int8_t)pExprInfo->type;
     pFillCol[i].col.offset = offset;
     pFillCol[i].flag       = TSDB_COL_NORMAL;    // always be ta normal column for table query
     pFillCol[i].functionId = pExprInfo->base.functionId;
     pFillCol[i].fillVal.i = pQuery->fillVal[i];
-    
+
     offset += pExprInfo->bytes;
   }
-  
+
   return pFillCol;
 }
 
@@ -4272,13 +4382,16 @@ int32_t doInitQInfo(SQInfo *pQInfo, STSBuf *pTsBuf, void *tsdb, int32_t vgId, bo
   pRuntimeEnv->hasTagResults = hasTagValOutput(pQuery);
 
   setScanLimitationByResultBuffer(pQuery);
+
+  // NOTE: pTableCheckInfo need to update the query time range and the lastKey info
+  // TODO fixme
   changeExecuteScanOrder(pQInfo, false);
 
   code = setupQueryHandle(tsdb, pQInfo, isSTableQuery);
   if (code != TSDB_CODE_SUCCESS) {
     return code;
   }
-  
+
   pQInfo->tsdb = tsdb;
   pQInfo->vgId = vgId;
 
@@ -4423,7 +4536,17 @@ static int64_t scanMultiTableDataBlocks(SQInfo *pQInfo) {
     }
 
     pQuery->current = *pTableQueryInfo;
-    CHECK_QUERY_TIME_RANGE(pQuery, *pTableQueryInfo);
+    if (QUERY_IS_ASC_QUERY(pQuery)) {
+      assert(
+          ((*pTableQueryInfo)->win.skey <= (*pTableQueryInfo)->win.ekey) &&
+          ((*pTableQueryInfo)->lastKey >= (*pTableQueryInfo)->win.skey) &&
+          ((*pTableQueryInfo)->win.skey >= pQuery->window.skey && (*pTableQueryInfo)->win.ekey <= pQuery->window.ekey));
+    } else {
+      assert(
+          ((*pTableQueryInfo)->win.skey >= (*pTableQueryInfo)->win.ekey) &&
+          ((*pTableQueryInfo)->lastKey <= (*pTableQueryInfo)->win.skey) &&
+          ((*pTableQueryInfo)->win.skey <= pQuery->window.skey && (*pTableQueryInfo)->win.ekey >= pQuery->window.ekey));
+    }
 
     if (!pRuntimeEnv->groupbyNormalCol) {
       setEnvForEachBlock(pQInfo, *pTableQueryInfo, &blockInfo);
@@ -4439,8 +4562,10 @@ static int64_t scanMultiTableDataBlocks(SQInfo *pQInfo) {
     summary->totalRows += blockInfo.rows;
     stableApplyFunctionsOnBlock(pRuntimeEnv, &blockInfo, pStatis, pDataBlock, binarySearchForKey);
   
-    qDebug("QInfo:%p check data block, uid:%"PRId64", tid:%d, brange:%" PRId64 "-%" PRId64 ", numOfRows:%d, lastKey:%" PRId64,
-           pQInfo, blockInfo.uid, blockInfo.tid, blockInfo.window.skey, blockInfo.window.ekey, blockInfo.rows, pQuery->current->lastKey);
+    qDebug("QInfo:%p check data block completed, uid:%"PRId64", tid:%d, brange:%" PRId64 "-%" PRId64 ", numOfRows:%d, "
+           "lastKey:%" PRId64,
+           pQInfo, blockInfo.uid, blockInfo.tid, blockInfo.window.skey, blockInfo.window.ekey, blockInfo.rows,
+           pQuery->current->lastKey);
   }
 
   if (terrno != TSDB_CODE_SUCCESS) {
@@ -4501,8 +4626,7 @@ static bool multiTableMultioutputHelper(SQInfo *pQInfo, int32_t index) {
 
   if (pRuntimeEnv->pTSBuf != NULL) {
     if (pRuntimeEnv->cur.vgroupIndex == -1) {
-      int64_t tag = pRuntimeEnv->pCtx[0].tag.i64Key;
-      STSElem elem = tsBufGetElemStartPos(pRuntimeEnv->pTSBuf, 0, tag);
+      STSElem elem = tsBufGetElemStartPos(pRuntimeEnv->pTSBuf, 0, &pRuntimeEnv->pCtx[0].tag);
 
       // failed to find data with the specified tag value
       if (elem.vnode < 0) {
@@ -4552,7 +4676,7 @@ static void sequentialTableProcess(SQInfo *pQInfo) {
       SArray *g1 = taosArrayInit(1, POINTER_BYTES);
       SArray *tx = taosArrayClone(group);
       taosArrayPush(g1, &tx);
-      
+
       STableGroupInfo gp = {.numOfTables = taosArrayGetSize(tx), .pGroupList = g1};
 
       // include only current table
@@ -4560,9 +4684,9 @@ static void sequentialTableProcess(SQInfo *pQInfo) {
         tsdbCleanupQueryHandle(pRuntimeEnv->pQueryHandle);
         pRuntimeEnv->pQueryHandle = NULL;
       }
-      
+
       if (isFirstLastRowQuery(pQuery)) {
-        pRuntimeEnv->pQueryHandle = tsdbQueryLastRow(pQInfo->tsdb, &cond, &gp, pQInfo);
+        assert(0);  // last_row query switch to other routine to handle
       } else {
         pRuntimeEnv->pQueryHandle = tsdbQueryRowsInExternalWindow(pQInfo->tsdb, &cond, &gp, pQInfo);
       }
@@ -4574,10 +4698,10 @@ static void sequentialTableProcess(SQInfo *pQInfo) {
       }
 
       initCtxOutputBuf(pRuntimeEnv);
-      
+
       SArray* s = tsdbGetQueriedTableList(pRuntimeEnv->pQueryHandle);
       assert(taosArrayGetSize(s) >= 1);
-      
+
       setTagVal(pRuntimeEnv, taosArrayGetP(s, 0), pQInfo->tsdb);
       if (isFirstLastRowQuery(pQuery)) {
         assert(taosArrayGetSize(s) == 1);
@@ -4590,13 +4714,13 @@ static void sequentialTableProcess(SQInfo *pQInfo) {
       pQuery->current = taosArrayGetP(first, 0);
 
       scanOneTableDataBlocks(pRuntimeEnv, pQuery->current->lastKey);
-      
+
       int64_t numOfRes = getNumOfResult(pRuntimeEnv);
       if (numOfRes > 0) {
         pQuery->rec.rows += numOfRes;
         forwardCtxOutputBuf(pRuntimeEnv, numOfRes);
       }
-      
+
       skipResults(pRuntimeEnv);
       pQInfo->groupIndex += 1;
 
@@ -4655,18 +4779,17 @@ static void sequentialTableProcess(SQInfo *pQInfo) {
       SWindowResInfo *pWindowResInfo = &pRuntimeEnv->windowResInfo;
 
         // no results generated for current group, continue to try the next group
-      taosArrayDestroy(s); 
+      taosArrayDestroy(s);
       if (pWindowResInfo->size <= 0) {
         continue;
       }
 
       for (int32_t i = 0; i < pWindowResInfo->size; ++i) {
-        SWindowStatus *pStatus = &pWindowResInfo->pResult[i].status;
-        pStatus->closed = true;  // enable return all results for group by normal columns
+        pWindowResInfo->pResult[i].closed = true; // enable return all results for group by normal columns
 
         SWindowResult *pResult = &pWindowResInfo->pResult[i];
         for (int32_t j = 0; j < pQuery->numOfOutput; ++j) {
-          pResult->numOfRows = MAX(pResult->numOfRows, pResult->resultInfo[j].numOfRes);
+          pResult->numOfRows = (uint16_t)(MAX(pResult->numOfRows, pResult->resultInfo[j].numOfRes));
         }
       }
 
@@ -4816,11 +4939,11 @@ static void doSaveContext(SQInfo *pQInfo) {
   SET_REVERSE_SCAN_FLAG(pRuntimeEnv);
   SWAP(pQuery->window.skey, pQuery->window.ekey, TSKEY);
   SWITCH_ORDER(pQuery->order.order);
-  
+
   if (pRuntimeEnv->pTSBuf != NULL) {
     pRuntimeEnv->pTSBuf->cur.order = pQuery->order.order;
   }
-  
+
   STsdbQueryCond cond = {
       .order   = pQuery->order.order,
       .colList = pQuery->colList,
@@ -4924,7 +5047,6 @@ static void multiTableQueryProcess(SQInfo *pQInfo) {
     el = scanMultiTableDataBlocks(pQInfo);
     qDebug("QInfo:%p reversed scan completed, elapsed time: %" PRId64 "ms", pQInfo, el);
 
-//    doCloseAllTimeWindowAfterScan(pQInfo);
     doRestoreContext(pQInfo);
   } else {
     qDebug("QInfo:%p no need to do reversed scan, query completed", pQInfo);
@@ -4962,14 +5084,14 @@ static void multiTableQueryProcess(SQInfo *pQInfo) {
  */
 static void tableFixedOutputProcess(SQInfo *pQInfo, STableQueryInfo* pTableInfo) {
   SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
-  
+
   SQuery *pQuery = pRuntimeEnv->pQuery;
   if (!pRuntimeEnv->topBotQuery && pQuery->limit.offset > 0) {  // no need to execute, since the output will be ignore.
     return;
   }
-  
+
   pQuery->current = pTableInfo;  // set current query table info
-  
+
   scanOneTableDataBlocks(pRuntimeEnv, pTableInfo->lastKey);
   finalizeQueryResult(pRuntimeEnv);
 
@@ -4987,10 +5109,10 @@ static void tableFixedOutputProcess(SQInfo *pQInfo, STableQueryInfo* pTableInfo)
 
 static void tableMultiOutputProcess(SQInfo *pQInfo, STableQueryInfo* pTableInfo) {
   SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
-  
+
   SQuery *pQuery = pRuntimeEnv->pQuery;
   pQuery->current = pTableInfo;
-  
+
   // for ts_comp query, re-initialized is not allowed
   if (!isTSCompQuery(pQuery)) {
     resetCtxOutputBuf(pRuntimeEnv);
@@ -5081,7 +5203,7 @@ static void tableIntervalProcess(SQInfo *pQInfo, STableQueryInfo* pTableInfo) {
 
   int32_t numOfFilled = 0;
   TSKEY newStartKey = TSKEY_INITIAL_VAL;
-  
+
   // skip blocks without load the actual data block from file if no filter condition present
   skipTimeInterval(pRuntimeEnv, &newStartKey);
   if (pQuery->limit.offset > 0 && pQuery->numOfFilterCols == 0 && pRuntimeEnv->pFillInfo == NULL) {
@@ -5108,7 +5230,7 @@ static void tableIntervalProcess(SQInfo *pQInfo, STableQueryInfo* pTableInfo) {
       taosFillSetStartInfo(pRuntimeEnv->pFillInfo, (int32_t)pQuery->rec.rows, pQuery->window.ekey);
       taosFillCopyInputDataFromFilePage(pRuntimeEnv->pFillInfo, (tFilePage**) pQuery->sdata);
       numOfFilled = 0;
-      
+
       pQuery->rec.rows = doFillGapsInResults(pRuntimeEnv, (tFilePage **)pQuery->sdata, &numOfFilled);
       if (pQuery->rec.rows > 0 || Q_STATUS_EQUAL(pQuery->status, QUERY_COMPLETED)) {
         limitResults(pRuntimeEnv);
@@ -5174,11 +5296,11 @@ static void tableQueryImpl(SQInfo *pQInfo) {
   // number of points returned during this query
   pQuery->rec.rows = 0;
   int64_t st = taosGetTimestampUs();
-  
+
   assert(pQInfo->tableqinfoGroupInfo.numOfTables == 1);
   SArray* g = GET_TABLEGROUP(pQInfo, 0);
   STableQueryInfo* item = taosArrayGetP(g, 0);
-  
+
   // group by normal column, sliding window query, interval query are handled by interval query processor
   if (QUERY_IS_INTERVAL_QUERY(pQuery) || pRuntimeEnv->groupbyNormalCol) {  // interval (down sampling operation)
     tableIntervalProcess(pQInfo, item);
@@ -5202,15 +5324,13 @@ static void stableQueryImpl(SQInfo *pQInfo) {
   int64_t st = taosGetTimestampUs();
 
   if (QUERY_IS_INTERVAL_QUERY(pQuery) ||
-      (isFixedOutputQuery(pRuntimeEnv) && (!isPointInterpoQuery(pQuery)) && !pRuntimeEnv->groupbyNormalCol &&
-      !isFirstLastRowQuery(pQuery))) {
+      (isFixedOutputQuery(pRuntimeEnv) && (!isPointInterpoQuery(pQuery)) && (!pRuntimeEnv->groupbyNormalCol))) {
     multiTableQueryProcess(pQInfo);
   } else {
     assert((pQuery->checkBuffer == 1 && pQuery->intervalTime == 0) || isPointInterpoQuery(pQuery) ||
             isFirstLastRowQuery(pQuery) || pRuntimeEnv->groupbyNormalCol);
 
     sequentialTableProcess(pQInfo);
-
   }
 
   // record the total elapsed time
@@ -5222,7 +5342,7 @@ static int32_t getColumnIndexInSource(SQueryTableMsg *pQueryMsg, SSqlFuncMsg *pE
 
   if (TSDB_COL_IS_TAG(pExprMsg->colInfo.flag)) {
     if (pExprMsg->colInfo.colId == TSDB_TBNAME_COLUMN_INDEX) {
-      return -1;
+      return TSDB_TBNAME_COLUMN_INDEX;
     }
 
     while(j < pQueryMsg->numOfTags) {
@@ -5233,6 +5353,8 @@ static int32_t getColumnIndexInSource(SQueryTableMsg *pQueryMsg, SSqlFuncMsg *pE
       j += 1;
     }
 
+  } else if (pExprMsg->colInfo.flag == TSDB_COL_UDC) {  // user specified column data
+    return TSDB_UD_COLUMN_INDEX;
   } else {
     while (j < pQueryMsg->numOfCols) {
       if (pExprMsg->colInfo.colId == pQueryMsg->colList[j].colId) {
@@ -5371,11 +5493,15 @@ static int32_t convertQueryMsg(SQueryTableMsg *pQueryMsg, SArray **pTableIdList,
     int32_t numOfFilters = pColInfo->numOfFilters;
     if (numOfFilters > 0) {
       pColInfo->filters = calloc(numOfFilters, sizeof(SColumnFilterInfo));
+      if (pColInfo->filters == NULL) {
+        code = TSDB_CODE_QRY_OUT_OF_MEMORY;
+        goto _cleanup;
+      }
     }
 
     for (int32_t f = 0; f < numOfFilters; ++f) {
       SColumnFilterInfo *pFilterMsg = (SColumnFilterInfo *)pMsg;
-      
+
       SColumnFilterInfo *pColFilter = &pColInfo->filters[f];
       pColFilter->filterstr = htons(pFilterMsg->filterstr);
 
@@ -5385,6 +5511,11 @@ static int32_t convertQueryMsg(SQueryTableMsg *pQueryMsg, SArray **pTableIdList,
         pColFilter->len = htobe64(pFilterMsg->len);
 
         pColFilter->pz = (int64_t)calloc(1, (size_t)(pColFilter->len + 1 * TSDB_NCHAR_SIZE)); // note: null-terminator
+        if (pColFilter->pz == 0) {
+          code = TSDB_CODE_QRY_OUT_OF_MEMORY;
+          goto _cleanup;
+        }
+
         memcpy((void *)pColFilter->pz, pMsg, (size_t)pColFilter->len);
         pMsg += (pColFilter->len + 1);
       } else {
@@ -5398,6 +5529,11 @@ static int32_t convertQueryMsg(SQueryTableMsg *pQueryMsg, SArray **pTableIdList,
   }
 
   *pExpr = calloc(pQueryMsg->numOfOutput, POINTER_BYTES);
+  if (*pExpr == NULL) {
+    code = TSDB_CODE_QRY_OUT_OF_MEMORY;
+    goto _cleanup;
+  }
+
   SSqlFuncMsg *pExprMsg = (SSqlFuncMsg *)pMsg;
 
   for (int32_t i = 0; i < pQueryMsg->numOfOutput; ++i) {
@@ -5484,6 +5620,11 @@ static int32_t convertQueryMsg(SQueryTableMsg *pQueryMsg, SArray **pTableIdList,
 
   if (pQueryMsg->numOfTags > 0) {
     (*tagCols) = calloc(1, sizeof(SColumnInfo) * pQueryMsg->numOfTags);
+    if (*tagCols == NULL) {
+      code = TSDB_CODE_QRY_OUT_OF_MEMORY;
+      goto _cleanup;
+    }
+
     for (int32_t i = 0; i < pQueryMsg->numOfTags; ++i) {
       SColumnInfo* pTagCol = (SColumnInfo*) pMsg;
 
@@ -5500,6 +5641,12 @@ static int32_t convertQueryMsg(SQueryTableMsg *pQueryMsg, SArray **pTableIdList,
   // the tag query condition expression string is located at the end of query msg
   if (pQueryMsg->tagCondLen > 0) {
     *tagCond = calloc(1, pQueryMsg->tagCondLen);
+
+    if (*tagCond == NULL) {
+      code = TSDB_CODE_QRY_OUT_OF_MEMORY;
+      goto _cleanup;
+
+    }
     memcpy(*tagCond, pMsg, pQueryMsg->tagCondLen);
     pMsg += pQueryMsg->tagCondLen;
   }
@@ -5591,9 +5738,19 @@ static int32_t createQFunctionExprFromMsg(SQueryTableMsg *pQueryMsg, SExprInfo *
       bytes = tDataTypeDesc[type].nSize;
     } else if (pExprs[i].base.colInfo.colId == TSDB_TBNAME_COLUMN_INDEX && pExprs[i].base.functionId == TSDB_FUNC_TAGPRJ) {  // parse the normal column
       SSchema s = tGetTableNameColumnSchema();
-      type  = s.type;
+      type = s.type;
       bytes = s.bytes;
-    } else{
+    } else if (pExprs[i].base.colInfo.colId <= TSDB_UD_COLUMN_INDEX) {
+      // it is a user-defined constant value column
+      assert(pExprs[i].base.functionId == TSDB_FUNC_PRJ);
+
+      type = pExprs[i].base.arg[1].argType;
+      bytes = pExprs[i].base.arg[1].argBytes;
+
+      if (type == TSDB_DATA_TYPE_BINARY || type == TSDB_DATA_TYPE_NCHAR) {
+        bytes += VARSTR_HEADER_SIZE;
+      }
+    } else {
       int32_t j = getColumnIndexInSource(pQueryMsg, &pExprs[i].base, pTagCols);
       assert(j < pQueryMsg->numOfCols || j < pQueryMsg->numOfTags);
 
@@ -5629,18 +5786,19 @@ static int32_t createQFunctionExprFromMsg(SQueryTableMsg *pQueryMsg, SExprInfo *
 
     if (functId == TSDB_FUNC_TOP || functId == TSDB_FUNC_BOTTOM) {
       int32_t j = getColumnIndexInSource(pQueryMsg, &pExprs[i].base, pTagCols);
-      assert(j < pQueryMsg->numOfCols);
-
-      SColumnInfo *pCol = &pQueryMsg->colList[j];
-
-      int32_t ret =
-        getResultDataInfo(pCol->type, pCol->bytes, functId, (int32_t)pExprs[i].base.arg[0].argValue.i64,
-                            &pExprs[i].type, &pExprs[i].bytes, &pExprs[i].interBytes, tagLen, isSuperTable);
-      assert(ret == TSDB_CODE_SUCCESS);
+      if (j < 0 || j >= pQueryMsg->numOfCols) {
+        assert(0);
+      } else {
+        SColumnInfo *pCol = &pQueryMsg->colList[j];
+        int32_t ret =
+            getResultDataInfo(pCol->type, pCol->bytes, functId, (int32_t)pExprs[i].base.arg[0].argValue.i64,
+                              &pExprs[i].type, &pExprs[i].bytes, &pExprs[i].interBytes, tagLen, isSuperTable);
+        assert(ret == TSDB_CODE_SUCCESS);
+      }
     }
   }
-  *pExprInfo = pExprs;
 
+  *pExprInfo = pExprs;
   return TSDB_CODE_SUCCESS;
 }
 
@@ -5680,6 +5838,9 @@ static int32_t createFilterInfo(void *pQInfo, SQuery *pQuery) {
   }
 
   pQuery->pFilterInfo = calloc(1, sizeof(SSingleColumnFilterInfo) * pQuery->numOfFilterCols);
+  if (pQuery->pFilterInfo == NULL) {
+    return TSDB_CODE_QRY_OUT_OF_MEMORY;
+  }
 
   for (int32_t i = 0, j = 0; i < pQuery->numOfCols; ++i) {
     if (pQuery->colList[i].numOfFilters > 0) {
@@ -5690,6 +5851,9 @@ static int32_t createFilterInfo(void *pQInfo, SQuery *pQuery) {
 
       pFilterInfo->numOfFilters = pQuery->colList[i].numOfFilters;
       pFilterInfo->pFilters = calloc(pFilterInfo->numOfFilters, sizeof(SColumnFilterElem));
+      if (pFilterInfo->pFilters == NULL) {
+        return TSDB_CODE_QRY_OUT_OF_MEMORY;
+      }
 
       for (int32_t f = 0; f < pFilterInfo->numOfFilters; ++f) {
         SColumnFilterElem *pSingleColFilter = &pFilterInfo->pFilters[f];
@@ -5766,7 +5930,7 @@ static void doUpdateExprColumnIndex(SQuery *pQuery) {
 
     // todo opt performance
     SColIndex *pColIndex = &pSqlExprMsg->colInfo;
-    if (!TSDB_COL_IS_TAG(pColIndex->flag)) {
+    if (TSDB_COL_IS_NORMAL_COL(pColIndex->flag)) {
       int32_t f = 0;
       for (f = 0; f < pQuery->numOfCols; ++f) {
         if (pColIndex->colId == pQuery->colList[f].colId) {
@@ -5774,8 +5938,10 @@ static void doUpdateExprColumnIndex(SQuery *pQuery) {
           break;
         }
       }
-      
-      assert (f < pQuery->numOfCols);
+
+      assert(f < pQuery->numOfCols);
+    } else if (pColIndex->colId <= TSDB_UD_COLUMN_INDEX) {
+      // do nothing for user-defined constant value result columns
     } else {
       int32_t f = 0;
       for (f = 0; f < pQuery->numOfTags; ++f) {
@@ -5784,7 +5950,7 @@ static void doUpdateExprColumnIndex(SQuery *pQuery) {
           break;
         }
       }
-      
+
       assert(f < pQuery->numOfTags || pColIndex->colId == TSDB_TBNAME_COLUMN_INDEX);
     }
   }
@@ -5837,6 +6003,7 @@ static SQInfo *createQInfoImpl(SQueryTableMsg *pQueryMsg, SArray* pTableIdList,
   if (pQuery == NULL) {
     goto _cleanup_query;
   }
+
   pQInfo->runtimeEnv.pQuery = pQuery;
 
   pQuery->numOfCols       = numOfCols;
@@ -5922,6 +6089,10 @@ static SQInfo *createQInfoImpl(SQueryTableMsg *pQueryMsg, SArray* pTableIdList,
 
   pQInfo->runtimeEnv.interBufSize = getOutputInterResultBufSize(pQuery);
   pQInfo->pBuf = calloc(pTableGroupInfo->numOfTables, sizeof(STableQueryInfo));
+  if (pQInfo->pBuf == NULL) {
+    goto _cleanup;
+  }
+
   int32_t index = 0;
 
   for(int32_t i = 0; i < numOfGroups; ++i) {
@@ -5932,20 +6103,18 @@ static SQInfo *createQInfoImpl(SQueryTableMsg *pQueryMsg, SArray* pTableIdList,
     if (p1 == NULL) {
       goto _cleanup;
     }
+
     taosArrayPush(pQInfo->tableqinfoGroupInfo.pGroupList, &p1);
 
     for(int32_t j = 0; j < s; ++j) {
       STableKeyInfo* info = taosArrayGet(pa, j);
+
       STableId* id = TSDB_TABLEID(info->pTable);
-
       STableIdInfo* pTableId = taosArraySearch(pTableIdList, id, compareTableIdInfo);
-      if (pTableId != NULL ) {
-        window.skey = pTableId->key;
-      } else {
-        window.skey = pQueryMsg->window.skey;
-      }
 
+      window.skey = (pTableId != NULL)? pTableId->key:pQueryMsg->window.skey;
       void* buf = (char*)pQInfo->pBuf + index * sizeof(STableQueryInfo);
+
       STableQueryInfo* item = createTableQueryInfo(&pQInfo->runtimeEnv, info->pTable, window, buf);
       if (item == NULL) {
         goto _cleanup;
@@ -6040,7 +6209,7 @@ static int32_t initQInfo(SQueryTableMsg *pQueryMsg, void *tsdb, int32_t vgId, SQ
   if ((code = doInitQInfo(pQInfo, pTSBuf, tsdb, vgId, isSTable)) != TSDB_CODE_SUCCESS) {
     goto _error;
   }
-  
+
   return code;
 
 _error:
@@ -6066,35 +6235,59 @@ static void freeQInfo(SQInfo *pQInfo) {
     return;
   }
 
-  SQuery *pQuery = pQInfo->runtimeEnv.pQuery;
   qDebug("QInfo:%p start to free QInfo", pQInfo);
-  for (int32_t col = 0; col < pQuery->numOfOutput; ++col) {
-    taosTFree(pQuery->sdata[col]);
-  }
 
   teardownQueryRuntimeEnv(&pQInfo->runtimeEnv);
 
-  for (int32_t i = 0; i < pQuery->numOfFilterCols; ++i) {
-    SSingleColumnFilterInfo *pColFilter = &pQuery->pFilterInfo[i];
-    if (pColFilter->numOfFilters > 0) {
-      taosTFree(pColFilter->pFilters);
+  SQuery *pQuery = pQInfo->runtimeEnv.pQuery;
+  if (pQuery != NULL) {
+    if (pQuery->sdata != NULL) {
+      for (int32_t col = 0; col < pQuery->numOfOutput; ++col) {
+        taosTFree(pQuery->sdata[col]);
+      }
+      taosTFree(pQuery->sdata);
     }
-  }
 
-  if (pQuery->pSelectExpr != NULL) {
-    for (int32_t i = 0; i < pQuery->numOfOutput; ++i) {
-      SExprInfo* pExprInfo = &pQuery->pSelectExpr[i];
+    if (pQuery->fillVal != NULL) {
+      taosTFree(pQuery->fillVal);
+    }
 
-      if (pExprInfo->pExpr != NULL) {
-        tExprTreeDestroy(&pExprInfo->pExpr, NULL);
+    for (int32_t i = 0; i < pQuery->numOfFilterCols; ++i) {
+      SSingleColumnFilterInfo *pColFilter = &pQuery->pFilterInfo[i];
+      if (pColFilter->numOfFilters > 0) {
+        taosTFree(pColFilter->pFilters);
       }
     }
 
-    taosTFree(pQuery->pSelectExpr);
-  }
+    if (pQuery->pSelectExpr != NULL) {
+      for (int32_t i = 0; i < pQuery->numOfOutput; ++i) {
+        SExprInfo *pExprInfo = &pQuery->pSelectExpr[i];
 
-  if (pQuery->fillVal != NULL) {
-    taosTFree(pQuery->fillVal);
+        if (pExprInfo->pExpr != NULL) {
+          tExprTreeDestroy(&pExprInfo->pExpr, NULL);
+        }
+      }
+
+      taosTFree(pQuery->pSelectExpr);
+    }
+
+    if (pQuery->pGroupbyExpr != NULL) {
+      taosArrayDestroy(pQuery->pGroupbyExpr->columnInfo);
+      taosTFree(pQuery->pGroupbyExpr);
+    }
+
+    taosTFree(pQuery->tagColList);
+    taosTFree(pQuery->pFilterInfo);
+
+    if (pQuery->colList != NULL) {
+      for (int32_t i = 0; i < pQuery->numOfCols; i++) {
+        SColumnInfo *column = pQuery->colList + i;
+        freeColumnFilterInfo(column->filters, column->numOfFilters);
+      }
+      taosTFree(pQuery->colList);
+    }
+
+    taosTFree(pQuery);
   }
 
   // todo refactor, extract method to destroytableDataInfo
@@ -6118,25 +6311,8 @@ static void freeQInfo(SQInfo *pQInfo) {
   taosHashCleanup(pQInfo->tableqinfoGroupInfo.map);
   tsdbDestroyTableGroup(&pQInfo->tableGroupInfo);
   taosArrayDestroy(pQInfo->arrTableIdInfo);
-  
-  if (pQuery->pGroupbyExpr != NULL) {
-    taosArrayDestroy(pQuery->pGroupbyExpr->columnInfo);
-    taosTFree(pQuery->pGroupbyExpr);
-  }
 
-  taosTFree(pQuery->tagColList);
-  taosTFree(pQuery->pFilterInfo);
 
-  if (pQuery->colList != NULL) {
-    for (int32_t i = 0; i < pQuery->numOfCols; i++) {
-      SColumnInfo* column = pQuery->colList + i;
-      freeColumnFilterInfo(column->filters, column->numOfFilters);
-    }
-    taosTFree(pQuery->colList);
-  }
-
-  taosTFree(pQuery->sdata);
-  taosTFree(pQuery);
   pQInfo->signature = 0;
 
   qDebug("QInfo:%p QInfo is freed", pQInfo);
@@ -6176,14 +6352,16 @@ static int32_t doDumpQueryResult(SQInfo *pQInfo, char *data) {
 
     // make sure file exist
     if (FD_VALID(fd)) {
-      int32_t s = lseek(fd, 0, SEEK_END);
-      UNUSED(s);
-      qDebug("QInfo:%p ts comp data return, file:%s, size:%d", pQInfo, pQuery->sdata[0]->data, s);
+      uint64_t s = lseek(fd, 0, SEEK_END);
+
+      qDebug("QInfo:%p ts comp data return, file:%s, size:%"PRId64, pQInfo, pQuery->sdata[0]->data, s);
       if (lseek(fd, 0, SEEK_SET) >= 0) {
-        size_t sz = read(fd, data, s);
-        UNUSED(sz);
+        size_t sz = read(fd, data, (uint32_t)s);
+        if(sz < s) {  // todo handle error
+          assert(0);
+        }
       } else {
-        // todo handle error
+        UNUSED(s);
       }
 
       close(fd);
@@ -6193,7 +6371,7 @@ static int32_t doDumpQueryResult(SQInfo *pQInfo, char *data) {
       qError("QInfo:%p failed to open tmp file to send ts-comp data to client, path:%s, reason:%s", pQInfo,
              pQuery->sdata[0]->data, strerror(errno));
       if (fd != -1) {
-        close(fd); 
+        close(fd);
       }
     }
 
@@ -6212,7 +6390,7 @@ static int32_t doDumpQueryResult(SQInfo *pQInfo, char *data) {
     qDebug("QInfo:%p results limitation reached, limitation:%"PRId64, pQInfo, pQuery->limit.limit);
     setQueryStatus(pQuery, QUERY_OVER);
   }
-  
+
   return TSDB_CODE_SUCCESS;
 }
 
@@ -6314,7 +6492,7 @@ int32_t qCreateQueryInfo(void* tsdb, int32_t vgId, SQueryTableMsg* pQueryMsg, qi
   pExprs = NULL;
   pGroupbyExpr = NULL;
   pTagColumnInfo = NULL;
-  
+
   if ((*pQInfo) == NULL) {
     code = TSDB_CODE_QRY_OUT_OF_MEMORY;
     goto _over;
@@ -6329,7 +6507,7 @@ _over:
   if (pGroupbyExpr != NULL) {
     taosArrayDestroy(pGroupbyExpr->columnInfo);
     free(pGroupbyExpr);
-  } 
+  }
   free(pTagColumnInfo);
   free(pExprs);
   free(pExprMsg);
@@ -6496,7 +6674,7 @@ int32_t qDumpRetrieveResult(qinfo_t qinfo, SRetrieveTableRsp **pRsp, int32_t *co
     (*pRsp)->offset   = 0;
     (*pRsp)->useconds = htobe64(pRuntimeEnv->summary.elapsedTime);
   }
-  
+
   (*pRsp)->precision = htons(pQuery->precision);
   if (pQuery->rec.rows > 0 && pQInfo->code == TSDB_CODE_SUCCESS) {
     doDumpQueryResult(pQInfo, (*pRsp)->data);
@@ -6573,7 +6751,7 @@ static void buildTagQueryResult(SQInfo* pQInfo) {
   if (numOfGroup == 0) {
     return;
   }
-  
+
   SArray* pa = GET_TABLEGROUP(pQInfo, 0);
 
   size_t num = taosArrayGetSize(pa);
@@ -6664,6 +6842,10 @@ static void buildTagQueryResult(SQInfo* pQInfo) {
       char *data = NULL, *dst = NULL;
       int16_t type = 0, bytes = 0;
       for(int32_t j = 0; j < pQuery->numOfOutput; ++j) {
+        // not assign value in case of user defined constant output column
+        if (pExprInfo[j].base.colInfo.flag == TSDB_COL_UDC) {
+          continue;
+        }
 
         if (pExprInfo[j].base.colInfo.colId == TSDB_TBNAME_COLUMN_INDEX) {
           bytes = tbnameSchema.bytes;
@@ -6674,7 +6856,7 @@ static void buildTagQueryResult(SQInfo* pQInfo) {
         } else {
           type = pExprInfo[j].type;
           bytes = pExprInfo[j].bytes;
-          
+
           data = tsdbGetTableTagVal(item->pTable, pExprInfo[j].base.colInfo.colId, type, bytes);
           dst = pQuery->sdata[j]->data + count * pExprInfo[j].bytes;
 
@@ -6710,12 +6892,16 @@ void freeqinfoFn(void *qhandle) {
 }
 
 void* qOpenQueryMgmt(int32_t vgId) {
-  const int32_t REFRESH_HANDLE_INTERVAL = 60; // every 30 seconds, refresh handle pool
+  const int32_t REFRESH_HANDLE_INTERVAL = 30; // every 30 seconds, refresh handle pool
 
   char cacheName[128] = {0};
   sprintf(cacheName, "qhandle_%d", vgId);
 
   SQueryMgmt* pQueryMgmt = calloc(1, sizeof(SQueryMgmt));
+  if (pQueryMgmt == NULL) {
+    terrno = TSDB_CODE_QRY_OUT_OF_MEMORY;
+    return NULL;
+  }
 
   pQueryMgmt->qinfoPool = taosCacheInit(TSDB_DATA_TYPE_BIGINT, REFRESH_HANDLE_INTERVAL, true, freeqinfoFn, cacheName);
   pQueryMgmt->closed    = false;
diff --git a/src/query/src/qParserImpl.c b/src/query/src/qParserImpl.c
index d8f12da642..9629f24cc2 100644
--- a/src/query/src/qParserImpl.c
+++ b/src/query/src/qParserImpl.c
@@ -33,7 +33,7 @@ SSqlInfo qSQLParse(const char *pStr) {
 
   int32_t i = 0;
   while (1) {
-    SSQLToken t0 = {0};
+    SStrToken t0 = {0};
 
     if (pStr[i] == 0) {
       Parse(pParser, 0, t0, &sqlInfo);
@@ -73,12 +73,12 @@ abort_parse:
   return sqlInfo;
 }
 
-tSQLExprList *tSQLExprListAppend(tSQLExprList *pList, tSQLExpr *pNode, SSQLToken *pToken) {
+tSQLExprList *tSQLExprListAppend(tSQLExprList *pList, tSQLExpr *pNode, SStrToken *pToken) {
   if (pList == NULL) {
     pList = calloc(1, sizeof(tSQLExprList));
   }
 
-  if (pList->nAlloc <= pList->nExpr) {  //
+  if (pList->nAlloc <= pList->nExpr) {
     pList->nAlloc = (pList->nAlloc << 1) + 4;
     pList->a = realloc(pList->a, pList->nAlloc * sizeof(pList->a[0]));
     if (pList->a == 0) {
@@ -117,41 +117,45 @@ void tSQLExprListDestroy(tSQLExprList *pList) {
   free(pList);
 }
 
-tSQLExpr *tSQLExprIdValueCreate(SSQLToken *pAliasToken, int32_t optrType) {
-  tSQLExpr *nodePtr = calloc(1, sizeof(tSQLExpr));
+tSQLExpr *tSQLExprIdValueCreate(SStrToken *pToken, int32_t optrType) {
+  tSQLExpr *pSQLExpr = calloc(1, sizeof(tSQLExpr));
+
+  if (pToken != NULL) {
+    pSQLExpr->token = *pToken;
+  }
 
   if (optrType == TK_INTEGER || optrType == TK_STRING || optrType == TK_FLOAT || optrType == TK_BOOL) {
-    toTSDBType(pAliasToken->type);
+    toTSDBType(pToken->type);
 
-    tVariantCreate(&nodePtr->val, pAliasToken);
-    nodePtr->nSQLOptr = optrType;
+    tVariantCreate(&pSQLExpr->val, pToken);
+    pSQLExpr->nSQLOptr = optrType;
   } else if (optrType == TK_NOW) {
     // default use microsecond
-    nodePtr->val.i64Key = taosGetTimestamp(TSDB_TIME_PRECISION_MICRO);
-    nodePtr->val.nType = TSDB_DATA_TYPE_BIGINT;
-    nodePtr->nSQLOptr = TK_TIMESTAMP;  // TK_TIMESTAMP used to denote the time value is in microsecond
+    pSQLExpr->val.i64Key = taosGetTimestamp(TSDB_TIME_PRECISION_MICRO);
+    pSQLExpr->val.nType = TSDB_DATA_TYPE_BIGINT;
+    pSQLExpr->nSQLOptr = TK_TIMESTAMP;  // TK_TIMESTAMP used to denote the time value is in microsecond
   } else if (optrType == TK_VARIABLE) {
-    int32_t ret = getTimestampInUsFromStr(pAliasToken->z, pAliasToken->n, &nodePtr->val.i64Key);
+    int32_t ret = getTimestampInUsFromStr(pToken->z, pToken->n, &pSQLExpr->val.i64Key);
     UNUSED(ret);
 
-    nodePtr->val.nType = TSDB_DATA_TYPE_BIGINT;
-    nodePtr->nSQLOptr = TK_TIMESTAMP;
+    pSQLExpr->val.nType = TSDB_DATA_TYPE_BIGINT;
+    pSQLExpr->nSQLOptr = TK_TIMESTAMP;
   } else {  // it must be the column name (tk_id) if it is not the number
     assert(optrType == TK_ID || optrType == TK_ALL);
-    if (pAliasToken != NULL) {
-      nodePtr->colInfo = *pAliasToken;
+    if (pToken != NULL) {
+      pSQLExpr->colInfo = *pToken;
     }
 
-    nodePtr->nSQLOptr = optrType;
+    pSQLExpr->nSQLOptr = optrType;
   }
-  return nodePtr;
+  return pSQLExpr;
 }
 
 /*
  * pList is the parameters for function with id(optType)
  * function name is denoted by pFunctionToken
  */
-tSQLExpr *tSQLExprCreateFunction(tSQLExprList *pList, SSQLToken *pFuncToken, SSQLToken *endToken, int32_t optType) {
+tSQLExpr *tSQLExprCreateFunction(tSQLExprList *pList, SStrToken *pFuncToken, SStrToken *endToken, int32_t optType) {
   if (pFuncToken == NULL) return NULL;
 
   tSQLExpr *pExpr = calloc(1, sizeof(tSQLExpr));
@@ -163,6 +167,8 @@ tSQLExpr *tSQLExprCreateFunction(tSQLExprList *pList, SSQLToken *pFuncToken, SSQ
 
   pExpr->operand.n = len;  // raw field name
   pExpr->operand.type = pFuncToken->type;
+
+  pExpr->token = pExpr->operand;
   return pExpr;
 }
 
@@ -173,8 +179,14 @@ tSQLExpr *tSQLExprCreateFunction(tSQLExprList *pList, SSQLToken *pFuncToken, SSQ
 tSQLExpr *tSQLExprCreate(tSQLExpr *pLeft, tSQLExpr *pRight, int32_t optrType) {
   tSQLExpr *pExpr = calloc(1, sizeof(tSQLExpr));
 
-  if (optrType == TK_PLUS || optrType == TK_MINUS || optrType == TK_STAR || optrType == TK_DIVIDE ||
-      optrType == TK_REM) {
+  if (pRight != NULL && pLeft != NULL) {
+    char* endPos = pRight->token.z + pRight->token.n;
+    pExpr->token.z = pLeft->token.z;
+    pExpr->token.n = (uint32_t)(endPos - pExpr->token.z);
+    pExpr->token.type = pLeft->token.type;
+  }
+
+  if (optrType == TK_PLUS || optrType == TK_MINUS || optrType == TK_STAR || optrType == TK_DIVIDE || optrType == TK_REM) {
     /*
      * if a token is noted as the TK_TIMESTAMP, the time precision is microsecond
      * Otherwise, the time precision is adaptive, determined by the time precision from databases.
@@ -373,7 +385,7 @@ void tVariantListDestroy(tVariantList *pList) {
   free(pList);
 }
 
-tVariantList *tVariantListAppendToken(tVariantList *pList, SSQLToken *pAliasToken, uint8_t sortOrder) {
+tVariantList *tVariantListAppendToken(tVariantList *pList, SStrToken *pToken, uint8_t sortOrder) {
   if (pList == NULL) {
     pList = calloc(1, sizeof(tVariantList));
   }
@@ -382,9 +394,9 @@ tVariantList *tVariantListAppendToken(tVariantList *pList, SSQLToken *pAliasToke
     return pList;
   }
 
-  if (pAliasToken) {
+  if (pToken) {
     tVariant t = {0};
-    tVariantCreate(&t, pAliasToken);
+    tVariantCreate(&t, pToken);
 
     tVariantListItem *pItem = &pList->a[pList->nExpr++];
     memcpy(pItem, &t, sizeof(tVariant));
@@ -420,7 +432,7 @@ void tFieldListDestroy(tFieldList *pList) {
   free(pList);
 }
 
-void setDBName(SSQLToken *pCpxName, SSQLToken *pDB) {
+void setDBName(SStrToken *pCpxName, SStrToken *pDB) {
   pCpxName->type = pDB->type;
   pCpxName->z = pDB->z;
   pCpxName->n = pDB->n;
@@ -464,7 +476,7 @@ int32_t getTimestampInUsFromStrImpl(int64_t val, char unit, int64_t *result) {
   return 0;
 }
 
-void tSQLSetColumnInfo(TAOS_FIELD *pField, SSQLToken *pName, TAOS_FIELD *pType) {
+void tSQLSetColumnInfo(TAOS_FIELD *pField, SStrToken *pName, TAOS_FIELD *pType) {
   int32_t maxLen = sizeof(pField->name) / sizeof(pField->name[0]);
   
   // truncate the column name
@@ -479,7 +491,7 @@ void tSQLSetColumnInfo(TAOS_FIELD *pField, SSQLToken *pName, TAOS_FIELD *pType)
   pField->bytes = pType->bytes;
 }
 
-void tSQLSetColumnType(TAOS_FIELD *pField, SSQLToken *type) {
+void tSQLSetColumnType(TAOS_FIELD *pField, SStrToken *type) {
   pField->type = -1;
 
   int32_t LENGTH_SIZE_OF_STR = 2;  // in case of nchar and binary, there two bytes to keep the length of binary|nchar.
@@ -517,9 +529,9 @@ void tSQLSetColumnType(TAOS_FIELD *pField, SSQLToken *type) {
 /*
  * extract the select info out of sql string
  */
-SQuerySQL *tSetQuerySQLElems(SSQLToken *pSelectToken, tSQLExprList *pSelection, tVariantList *pFrom, tSQLExpr *pWhere,
-                             tVariantList *pGroupby, tVariantList *pSortOrder, SSQLToken *pInterval,
-                             SSQLToken *pSliding, tVariantList *pFill, SLimitVal *pLimit, SLimitVal *pGLimit) {
+SQuerySQL *tSetQuerySQLElems(SStrToken *pSelectToken, tSQLExprList *pSelection, tVariantList *pFrom, tSQLExpr *pWhere,
+                             tVariantList *pGroupby, tVariantList *pSortOrder, SStrToken *pInterval,
+                             SStrToken *pSliding, tVariantList *pFill, SLimitVal *pLimit, SLimitVal *pGLimit) {
   assert(pSelection != NULL);
 
   SQuerySQL *pQuery = calloc(1, sizeof(SQuerySQL));
@@ -611,7 +623,7 @@ void destroyAllSelectClause(SSubclauseInfo *pClause) {
   taosTFree(pClause->pClause);
 }
 
-SCreateTableSQL *tSetCreateSQLElems(tFieldList *pCols, tFieldList *pTags, SSQLToken *pStableName,
+SCreateTableSQL *tSetCreateSQLElems(tFieldList *pCols, tFieldList *pTags, SStrToken *pStableName,
                                     tVariantList *pTagVals, SQuerySQL *pSelect, int32_t type) {
   SCreateTableSQL *pCreate = calloc(1, sizeof(SCreateTableSQL));
 
@@ -644,7 +656,7 @@ SCreateTableSQL *tSetCreateSQLElems(tFieldList *pCols, tFieldList *pTags, SSQLTo
   return pCreate;
 }
 
-SAlterTableSQL *tAlterTableSQLElems(SSQLToken *pMeterName, tFieldList *pCols, tVariantList *pVals, int32_t type) {
+SAlterTableSQL *tAlterTableSQLElems(SStrToken *pMeterName, tFieldList *pCols, tVariantList *pVals, int32_t type) {
   SAlterTableSQL *pAlterTable = calloc(1, sizeof(SAlterTableSQL));
   
   pAlterTable->name = *pMeterName;
@@ -716,7 +728,7 @@ SSubclauseInfo* setSubclause(SSubclauseInfo* pSubclause, void *pSqlExprInfo) {
   return pSubclause;
 }
 
-SSqlInfo* setSQLInfo(SSqlInfo *pInfo, void *pSqlExprInfo, SSQLToken *pMeterName, int32_t type) {
+SSqlInfo* setSQLInfo(SSqlInfo *pInfo, void *pSqlExprInfo, SStrToken *pMeterName, int32_t type) {
   pInfo->type = type;
   
   if (type == TSDB_SQL_SELECT) {
@@ -745,7 +757,7 @@ SSubclauseInfo* appendSelectClause(SSubclauseInfo *pQueryInfo, void *pSubclause)
   return pQueryInfo;
 }
 
-void setCreatedTableName(SSqlInfo *pInfo, SSQLToken *pMeterName, SSQLToken *pIfNotExists) {
+void setCreatedTableName(SSqlInfo *pInfo, SStrToken *pMeterName, SStrToken *pIfNotExists) {
   pInfo->pCreateTableInfo->name = *pMeterName;
   pInfo->pCreateTableInfo->existCheck = (pIfNotExists->n != 0);
 }
@@ -760,7 +772,7 @@ void tTokenListBuyMoreSpace(tDCLSQL *pTokenList) {
   }
 }
 
-tDCLSQL *tTokenListAppend(tDCLSQL *pTokenList, SSQLToken *pToken) {
+tDCLSQL *tTokenListAppend(tDCLSQL *pTokenList, SStrToken *pToken) {
   if (pToken == NULL) return NULL;
 
   if (pTokenList == NULL) pTokenList = calloc(1, sizeof(tDCLSQL));
@@ -781,19 +793,19 @@ void setDCLSQLElems(SSqlInfo *pInfo, int32_t type, int32_t nParam, ...) {
   va_start(va, nParam);
 
   while (nParam-- > 0) {
-    SSQLToken *pToken = va_arg(va, SSQLToken *);
+    SStrToken *pToken = va_arg(va, SStrToken *);
     pInfo->pDCLInfo = tTokenListAppend(pInfo->pDCLInfo, pToken);
   }
   va_end(va);
 }
 
-void setDropDBTableInfo(SSqlInfo *pInfo, int32_t type, SSQLToken* pToken, SSQLToken* existsCheck) {
+void setDropDBTableInfo(SSqlInfo *pInfo, int32_t type, SStrToken* pToken, SStrToken* existsCheck) {
   pInfo->type = type;
   pInfo->pDCLInfo = tTokenListAppend(pInfo->pDCLInfo, pToken);
   pInfo->pDCLInfo->existsCheck = (existsCheck->n == 1);
 }
 
-void setShowOptions(SSqlInfo *pInfo, int32_t type, SSQLToken* prefix, SSQLToken* pPatterns) {
+void setShowOptions(SSqlInfo *pInfo, int32_t type, SStrToken* prefix, SStrToken* pPatterns) {
   if (pInfo->pDCLInfo == NULL) {
     pInfo->pDCLInfo = calloc(1, sizeof(tDCLSQL));
   }
@@ -816,7 +828,7 @@ void setShowOptions(SSqlInfo *pInfo, int32_t type, SSQLToken* prefix, SSQLToken*
   }
 }
 
-void setCreateDBSQL(SSqlInfo *pInfo, int32_t type, SSQLToken *pToken, SCreateDBInfo *pDB, SSQLToken *pIgExists) {
+void setCreateDBSQL(SSqlInfo *pInfo, int32_t type, SStrToken *pToken, SCreateDBInfo *pDB, SStrToken *pIgExists) {
   pInfo->type = type;
   if (pInfo->pDCLInfo == NULL) {
     pInfo->pDCLInfo = calloc(1, sizeof(tDCLSQL));
@@ -827,7 +839,7 @@ void setCreateDBSQL(SSqlInfo *pInfo, int32_t type, SSQLToken *pToken, SCreateDBI
   pInfo->pDCLInfo->dbOpt.ignoreExists = pIgExists->n; // sql.y has: ifnotexists(X) ::= IF NOT EXISTS.   {X.n = 1;}
 }
 
-void setCreateAcctSQL(SSqlInfo *pInfo, int32_t type, SSQLToken *pName, SSQLToken *pPwd, SCreateAcctSQL *pAcctInfo) {
+void setCreateAcctSQL(SSqlInfo *pInfo, int32_t type, SStrToken *pName, SStrToken *pPwd, SCreateAcctSQL *pAcctInfo) {
   pInfo->type = type;
   if (pInfo->pDCLInfo == NULL) {
     pInfo->pDCLInfo = calloc(1, sizeof(tDCLSQL));
@@ -843,7 +855,7 @@ void setCreateAcctSQL(SSqlInfo *pInfo, int32_t type, SSQLToken *pName, SSQLToken
   }
 }
 
-void setCreateUserSQL(SSqlInfo *pInfo, SSQLToken *pName, SSQLToken *pPasswd) {
+void setCreateUserSQL(SSqlInfo *pInfo, SStrToken *pName, SStrToken *pPasswd) {
   pInfo->type = TSDB_SQL_CREATE_USER;
   if (pInfo->pDCLInfo == NULL) {
     pInfo->pDCLInfo = calloc(1, sizeof(tDCLSQL));
@@ -855,7 +867,7 @@ void setCreateUserSQL(SSqlInfo *pInfo, SSQLToken *pName, SSQLToken *pPasswd) {
   pInfo->pDCLInfo->user.passwd = *pPasswd;
 }
 
-void setAlterUserSQL(SSqlInfo *pInfo, int16_t type, SSQLToken *pName, SSQLToken* pPwd, SSQLToken *pPrivilege) {
+void setAlterUserSQL(SSqlInfo *pInfo, int16_t type, SStrToken *pName, SStrToken* pPwd, SStrToken *pPrivilege) {
   pInfo->type = TSDB_SQL_ALTER_USER;
   if (pInfo->pDCLInfo == NULL) {
     pInfo->pDCLInfo = calloc(1, sizeof(tDCLSQL));
@@ -880,7 +892,7 @@ void setAlterUserSQL(SSqlInfo *pInfo, int16_t type, SSQLToken *pName, SSQLToken*
   }
 }
 
-void setKillSQL(SSqlInfo *pInfo, int32_t type, SSQLToken *ip) {
+void setKillSQL(SSqlInfo *pInfo, int32_t type, SStrToken *ip) {
   pInfo->type = type;
   if (pInfo->pDCLInfo == NULL) {
     pInfo->pDCLInfo = calloc(1, sizeof(tDCLSQL));
@@ -909,5 +921,5 @@ void setDefaultCreateDbOption(SCreateDBInfo *pDBInfo) {
   pDBInfo->quorum = -1;
   pDBInfo->keep = NULL;
 
-  memset(&pDBInfo->precision, 0, sizeof(SSQLToken));
+  memset(&pDBInfo->precision, 0, sizeof(SStrToken));
 }
diff --git a/src/query/src/qResultbuf.c b/src/query/src/qResultbuf.c
index 18d2520542..b3e97459d3 100644
--- a/src/query/src/qResultbuf.c
+++ b/src/query/src/qResultbuf.c
@@ -137,8 +137,15 @@ static char* doFlushPageToDisk(SDiskbasedResultBuf* pResultBuf, SPageInfo* pg) {
     }
 
     //3. write to disk.
-    fseek(pResultBuf->file, pg->info.offset, SEEK_SET);
-    fwrite(t, size, 1, pResultBuf->file);
+    int32_t ret = fseek(pResultBuf->file, pg->info.offset, SEEK_SET);
+    if (ret != 0) {  // todo handle the error case
+
+    }
+
+    ret = (int32_t)fwrite(t, size, 1, pResultBuf->file);
+    if (ret != size) {  // todo handle the error case
+
+    }
 
     if (pResultBuf->fileSize < pg->info.offset + pg->info.length) {
       pResultBuf->fileSize = pg->info.offset + pg->info.length;
diff --git a/src/query/src/qTokenizer.c b/src/query/src/qTokenizer.c
index 227aded5f1..5fdabca166 100644
--- a/src/query/src/qTokenizer.c
+++ b/src/query/src/qTokenizer.c
@@ -85,7 +85,7 @@ static SKeyword keywordTable[] = {
     {"QUERIES",      TK_QUERIES},
     {"CONNECTIONS",  TK_CONNECTIONS},
     {"STREAMS",      TK_STREAMS},
-    {"CONFIGS",      TK_CONFIGS},
+    {"VARIABLES",    TK_VARIABLES},
     {"SCORES",       TK_SCORES},
     {"GRANTS",       TK_GRANTS},
     {"DOT",          TK_DOT},
@@ -580,8 +580,8 @@ uint32_t tSQLGetToken(char* z, uint32_t* tokenType) {
   return 0;
 }
 
-SSQLToken tStrGetToken(char* str, int32_t* i, bool isPrevOptr, uint32_t numOfIgnoreToken, uint32_t* ignoreTokenTypes) {
-  SSQLToken t0 = {0};
+SStrToken tStrGetToken(char* str, int32_t* i, bool isPrevOptr, uint32_t numOfIgnoreToken, uint32_t* ignoreTokenTypes) {
+  SStrToken t0 = {0};
 
   // here we reach the end of sql string, null-terminated string
   if (str[*i] == 0) {
diff --git a/src/query/src/qTsbuf.c b/src/query/src/qTsbuf.c
index 25eb33ff7d..b264f6cdc9 100644
--- a/src/query/src/qTsbuf.c
+++ b/src/query/src/qTsbuf.c
@@ -8,7 +8,6 @@ static void TSBufUpdateVnodeInfo(STSBuf* pTSBuf, int32_t index, STSVnodeBlockInf
 static STSBuf* allocResForTSBuf(STSBuf* pTSBuf);
 static int32_t STSBufUpdateHeader(STSBuf* pTSBuf, STSBufFileHeader* pHeader);
 
-
 /**
  * todo error handling
  * support auto closeable tmp file
@@ -76,7 +75,7 @@ STSBuf* tsBufCreateFromFile(const char* path, bool autoDelete) {
     return NULL;
   }
   
-  if ((int32_t)header.numOfVnode > pTSBuf->numOfAlloc) {
+  if (header.numOfVnode > pTSBuf->numOfAlloc) {
     pTSBuf->numOfAlloc = header.numOfVnode;
     STSVnodeBlockInfoEx* tmp = realloc(pTSBuf->pData, sizeof(STSVnodeBlockInfoEx) * pTSBuf->numOfAlloc);
     if (tmp == NULL) {
@@ -225,14 +224,15 @@ static void writeDataToDisk(STSBuf* pTSBuf) {
   }
   
   STSBlock* pBlock = &pTSBuf->block;
-  
-  pBlock->numOfElem = pTSBuf->tsData.len / TSDB_KEYSIZE;
+  STSList*  pTsData = &pTSBuf->tsData;
+
+  pBlock->numOfElem = pTsData->len / TSDB_KEYSIZE;
   pBlock->compLen =
-      tsCompressTimestamp(pTSBuf->tsData.rawBuf, pTSBuf->tsData.len, pTSBuf->tsData.len / TSDB_KEYSIZE, pBlock->payload,
-                          pTSBuf->tsData.allocSize, TWO_STAGE_COMP, pTSBuf->assistBuf, pTSBuf->bufSize);
+      tsCompressTimestamp(pTsData->rawBuf, pTsData->len, pTsData->len/TSDB_KEYSIZE, pBlock->payload, pTsData->allocSize,
+          TWO_STAGE_COMP, pTSBuf->assistBuf, pTSBuf->bufSize);
   
   int64_t r = fseek(pTSBuf->f, pTSBuf->fileSize, SEEK_SET);
-  UNUSED(r);
+  assert(r == 0);
   
   /*
    * format for output data:
@@ -241,16 +241,22 @@ static void writeDataToDisk(STSBuf* pTSBuf) {
    *
    * both side has the compressed length is used to support load data forwards/backwords.
    */
-  fwrite(&pBlock->tag, sizeof(pBlock->tag), 1, pTSBuf->f);
+  int32_t metaLen = 0;
+  metaLen += (int32_t)fwrite(&pBlock->tag.nType, 1, sizeof(pBlock->tag.nType), pTSBuf->f);
+  metaLen += (int32_t)fwrite(&pBlock->tag.nLen, 1, sizeof(pBlock->tag.nLen), pTSBuf->f);
+
+  if (pBlock->tag.nType == TSDB_DATA_TYPE_BINARY || pBlock->tag.nType == TSDB_DATA_TYPE_NCHAR) {
+    metaLen += (int32_t)fwrite(pBlock->tag.pz, 1, (size_t)pBlock->tag.nLen, pTSBuf->f);
+  } else if (pBlock->tag.nType != TSDB_DATA_TYPE_NULL) {
+    metaLen += (int32_t)fwrite(&pBlock->tag.i64Key, 1, sizeof(int64_t), pTSBuf->f);
+  }
+
   fwrite(&pBlock->numOfElem, sizeof(pBlock->numOfElem), 1, pTSBuf->f);
-  
   fwrite(&pBlock->compLen, sizeof(pBlock->compLen), 1, pTSBuf->f);
-  
   fwrite(pBlock->payload, (size_t)pBlock->compLen, 1, pTSBuf->f);
-  
   fwrite(&pBlock->compLen, sizeof(pBlock->compLen), 1, pTSBuf->f);
   
-  int32_t blockSize = sizeof(pBlock->tag) + sizeof(pBlock->numOfElem) + sizeof(pBlock->compLen) * 2 + pBlock->compLen;
+  int32_t blockSize = metaLen + sizeof(pBlock->numOfElem) + sizeof(pBlock->compLen) * 2 + pBlock->compLen;
   pTSBuf->fileSize += blockSize;
   
   pTSBuf->tsData.len = 0;
@@ -298,9 +304,24 @@ STSBlock* readDataFromDisk(STSBuf* pTSBuf, int32_t order, bool decomp) {
     ret = fseek(pTSBuf->f, -offset, SEEK_CUR);
     UNUSED(ret);
   }
-  
-  size_t sz = fread(&pBlock->tag, sizeof(pBlock->tag), 1, pTSBuf->f);
-  UNUSED(sz);
+
+  fread(&pBlock->tag.nType, sizeof(pBlock->tag.nType), 1, pTSBuf->f);
+  fread(&pBlock->tag.nLen, sizeof(pBlock->tag.nLen), 1, pTSBuf->f);
+
+  // NOTE: mix types tags are not supported
+  size_t sz = 0;
+  if (pBlock->tag.nType == TSDB_DATA_TYPE_BINARY || pBlock->tag.nType == TSDB_DATA_TYPE_NCHAR) {
+    char* tp = realloc(pBlock->tag.pz, pBlock->tag.nLen + 1);
+    assert(tp != NULL);
+
+    memset(tp, 0, pBlock->tag.nLen + 1);
+    pBlock->tag.pz = tp;
+
+    sz = fread(pBlock->tag.pz, (size_t)pBlock->tag.nLen, 1, pTSBuf->f);
+  } else if (pBlock->tag.nType != TSDB_DATA_TYPE_NULL) {
+    sz = fread(&pBlock->tag.i64Key, sizeof(int64_t), 1, pTSBuf->f);
+  }
+
   sz = fread(&pBlock->numOfElem, sizeof(pBlock->numOfElem), 1, pTSBuf->f);
   UNUSED(sz);
   sz = fread(&pBlock->compLen, sizeof(pBlock->compLen), 1, pTSBuf->f);
@@ -361,7 +382,7 @@ static int32_t setCheckTSOrder(STSBuf* pTSBuf, const char* pData, int32_t len) {
   return TSDB_CODE_SUCCESS;
 }
 
-void tsBufAppend(STSBuf* pTSBuf, int32_t vnodeId, int64_t tag, const char* pData, int32_t len) {
+void tsBufAppend(STSBuf* pTSBuf, int32_t vnodeId, tVariant* tag, const char* pData, int32_t len) {
   STSVnodeBlockInfoEx* pBlockInfo = NULL;
   STSList*             ptsData = &pTSBuf->tsData;
   
@@ -375,15 +396,15 @@ void tsBufAppend(STSBuf* pTSBuf, int32_t vnodeId, int64_t tag, const char* pData
   }
   
   assert(pBlockInfo->info.vnode == vnodeId);
-  
-  if (pTSBuf->block.tag != tag && ptsData->len > 0) {
+
+  if ((tVariantCompare(&pTSBuf->block.tag, tag) != 0) && ptsData->len > 0) {
     // new arrived data with different tags value, save current value into disk first
     writeDataToDisk(pTSBuf);
   } else {
     expandBuffer(ptsData, len);
   }
   
-  pTSBuf->block.tag = tag;
+  tVariantAssign(&pTSBuf->block.tag, tag);
   memcpy(ptsData->rawBuf + ptsData->len, pData, (size_t)len);
   
   // todo check return value
@@ -465,7 +486,7 @@ static int32_t tsBufFindBlock(STSBuf* pTSBuf, STSVnodeBlockInfo* pBlockInfo, int
   return 0;
 }
 
-static int32_t tsBufFindBlockByTag(STSBuf* pTSBuf, STSVnodeBlockInfo* pBlockInfo, int64_t tag) {
+static int32_t tsBufFindBlockByTag(STSBuf* pTSBuf, STSVnodeBlockInfo* pBlockInfo, tVariant* tag) {
   bool decomp = false;
   
   int64_t offset = 0;
@@ -484,7 +505,7 @@ static int32_t tsBufFindBlockByTag(STSBuf* pTSBuf, STSVnodeBlockInfo* pBlockInfo
       return -1;
     }
     
-    if (pTSBuf->block.tag == tag) {
+    if (tVariantCompare(&pTSBuf->block.tag, tag) == 0) {
       return i;
     }
   }
@@ -669,8 +690,8 @@ STSElem tsBufGetElem(STSBuf* pTSBuf) {
   
   elem1.vnode = pTSBuf->pData[pCur->vgroupIndex].info.vnode;
   elem1.ts = *(TSKEY*)(pTSBuf->tsData.rawBuf + pCur->tsIndex * TSDB_KEYSIZE);
-  elem1.tag = pBlock->tag;
-  
+  tVariantAssign(&elem1.tag, &pBlock->tag);
+
   return elem1;
 }
 
@@ -800,7 +821,7 @@ STSBuf* tsBufCreateFromCompBlocks(const char* pData, int32_t numOfBlocks, int32_
   return pTSBuf;
 }
 
-STSElem tsBufGetElemStartPos(STSBuf* pTSBuf, int32_t vnodeId, int64_t tag) {
+STSElem tsBufGetElemStartPos(STSBuf* pTSBuf, int32_t vnodeId, tVariant* tag) {
   STSElem elem = {.vnode = -1};
   
   if (pTSBuf == NULL) {
@@ -881,7 +902,9 @@ void tsBufDisplay(STSBuf* pTSBuf) {
   
   while (tsBufNextPos(pTSBuf)) {
     STSElem elem = tsBufGetElem(pTSBuf);
-    printf("%d-%" PRId64 "-%" PRId64 "\n", elem.vnode, elem.tag, elem.ts);
+    if (elem.tag.nType == TSDB_DATA_TYPE_BIGINT) {
+      printf("%d-%" PRId64 "-%" PRId64 "\n", elem.vnode, elem.tag.i64Key, elem.ts);
+    }
   }
   
   pTSBuf->cur.order = old;
diff --git a/src/query/src/qUtil.c b/src/query/src/qUtil.c
index a01eb33ec7..509362863c 100644
--- a/src/query/src/qUtil.c
+++ b/src/query/src/qUtil.c
@@ -45,8 +45,8 @@ int32_t initWindowResInfo(SWindowResInfo *pWindowResInfo, SQueryRuntimeEnv *pRun
   pWindowResInfo->curIndex = -1;
   pWindowResInfo->size     = 0;
   pWindowResInfo->prevSKey = TSKEY_INITIAL_VAL;
-  
-  pRuntimeEnv->summary.internalSupSize += sizeof(SWindowResult) * threshold;
+
+  SQueryCostInfo* pSummary = &pRuntimeEnv->summary;
 
   // use the pointer arraylist
   pWindowResInfo->pResult = calloc(threshold, sizeof(SWindowResult));
@@ -54,8 +54,11 @@ int32_t initWindowResInfo(SWindowResInfo *pWindowResInfo, SQueryRuntimeEnv *pRun
     return TSDB_CODE_QRY_OUT_OF_MEMORY;
   }
 
-  pRuntimeEnv->summary.internalSupSize += sizeof(SWindowResult) * threshold;
-  pRuntimeEnv->summary.internalSupSize += (pRuntimeEnv->pQuery->numOfOutput * sizeof(SResultInfo) + pRuntimeEnv->interBufSize) * pWindowResInfo->capacity;
+  pWindowResInfo->interval = pRuntimeEnv->pQuery->intervalTime;
+
+  pSummary->internalSupSize += sizeof(SWindowResult) * threshold;
+  pSummary->internalSupSize += (pRuntimeEnv->pQuery->numOfOutput * sizeof(SResultInfo) + pRuntimeEnv->interBufSize) * pWindowResInfo->capacity;
+  pSummary->numOfTimeWindows = threshold;
 
   for (int32_t i = 0; i < pWindowResInfo->capacity; ++i) {
     int32_t code = createQueryResultInfo(pRuntimeEnv->pQuery, &pWindowResInfo->pResult[i], pRuntimeEnv->stableQuery, pRuntimeEnv->interBufSize);
@@ -126,8 +129,8 @@ void clearFirstNTimeWindow(SQueryRuntimeEnv *pRuntimeEnv, int32_t num) {
   
   for (int32_t i = 0; i < num; ++i) {
     SWindowResult *pResult = &pWindowResInfo->pResult[i];
-    if (pResult->status.closed) {  // remove the window slot from hash table
-      taosHashRemove(pWindowResInfo->hashList, (const char *)&pResult->window.skey, pWindowResInfo->type);
+    if (pResult->closed) {  // remove the window slot from hash table
+      taosHashRemove(pWindowResInfo->hashList, (const char *)&pResult->skey, pWindowResInfo->type);
     } else {
       break;
     }
@@ -149,12 +152,12 @@ void clearFirstNTimeWindow(SQueryRuntimeEnv *pRuntimeEnv, int32_t num) {
   pWindowResInfo->size = remain;
   for (int32_t k = 0; k < pWindowResInfo->size; ++k) {
     SWindowResult *pResult = &pWindowResInfo->pResult[k];
-    int32_t *p = (int32_t *)taosHashGet(pWindowResInfo->hashList, (const char *)&pResult->window.skey,
+    int32_t *p = (int32_t *)taosHashGet(pWindowResInfo->hashList, (const char *)&pResult->skey,
         tDataTypeDesc[pWindowResInfo->type].nSize);
     assert(p != NULL); 
     int32_t  v = (*p - num);
     assert(v >= 0 && v <= pWindowResInfo->size);
-    taosHashPut(pWindowResInfo->hashList, (char *)&pResult->window.skey, tDataTypeDesc[pWindowResInfo->type].nSize,
+    taosHashPut(pWindowResInfo->hashList, (char *)&pResult->skey, tDataTypeDesc[pWindowResInfo->type].nSize,
         (char *)&v, sizeof(int32_t));
   }
   
@@ -173,7 +176,7 @@ void clearClosedTimeWindow(SQueryRuntimeEnv *pRuntimeEnv) {
 
 int32_t numOfClosedTimeWindow(SWindowResInfo *pWindowResInfo) {
   int32_t i = 0;
-  while (i < pWindowResInfo->size && pWindowResInfo->pResult[i].status.closed) {
+  while (i < pWindowResInfo->size && pWindowResInfo->pResult[i].closed) {
     ++i;
   }
   
@@ -184,11 +187,11 @@ void closeAllTimeWindow(SWindowResInfo *pWindowResInfo) {
   assert(pWindowResInfo->size >= 0 && pWindowResInfo->capacity >= pWindowResInfo->size);
   
   for (int32_t i = 0; i < pWindowResInfo->size; ++i) {
-    if (pWindowResInfo->pResult[i].status.closed) {
+    if (pWindowResInfo->pResult[i].closed) {
       continue;
     }
     
-    pWindowResInfo->pResult[i].status.closed = true;
+    pWindowResInfo->pResult[i].closed = true;
   }
 }
 
@@ -204,7 +207,7 @@ void removeRedundantWindow(SWindowResInfo *pWindowResInfo, TSKEY lastKey, int32_
   }
 
   // get the result order
-  int32_t resultOrder = (pWindowResInfo->pResult[0].window.skey < pWindowResInfo->pResult[1].window.skey)? 1:-1;
+  int32_t resultOrder = (pWindowResInfo->pResult[0].skey < pWindowResInfo->pResult[1].skey)? 1:-1;
 
   if (order != resultOrder) {
     return;
@@ -212,11 +215,12 @@ void removeRedundantWindow(SWindowResInfo *pWindowResInfo, TSKEY lastKey, int32_
 
   int32_t i = 0;
   if (order == QUERY_ASC_FORWARD_STEP) {
-    while (i < pWindowResInfo->size && (pWindowResInfo->pResult[i].window.ekey < lastKey)) {
+    TSKEY ekey = pWindowResInfo->pResult[i].skey + pWindowResInfo->interval;
+    while (i < pWindowResInfo->size && (ekey < lastKey)) {
       ++i;
     }
   } else if (order == QUERY_DESC_FORWARD_STEP) {
-    while (i < pWindowResInfo->size && (pWindowResInfo->pResult[i].window.skey > lastKey)) {
+    while (i < pWindowResInfo->size && (pWindowResInfo->pResult[i].skey > lastKey)) {
       ++i;
     }
   }
@@ -227,11 +231,11 @@ void removeRedundantWindow(SWindowResInfo *pWindowResInfo, TSKEY lastKey, int32_
 }
 
 bool isWindowResClosed(SWindowResInfo *pWindowResInfo, int32_t slot) {
-  return (getWindowResult(pWindowResInfo, slot)->status.closed == true);
+  return (getWindowResult(pWindowResInfo, slot)->closed == true);
 }
 
 void closeTimeWindow(SWindowResInfo *pWindowResInfo, int32_t slot) {
-  getWindowResult(pWindowResInfo, slot)->status.closed = true;
+  getWindowResult(pWindowResInfo, slot)->closed = true;
 }
 
 void clearTimeWindowResBuf(SQueryRuntimeEnv *pRuntimeEnv, SWindowResult *pWindowRes) {
@@ -253,8 +257,8 @@ void clearTimeWindowResBuf(SQueryRuntimeEnv *pRuntimeEnv, SWindowResult *pWindow
   
   pWindowRes->numOfRows = 0;
   pWindowRes->pos = (SPosInfo){-1, -1};
-  pWindowRes->status.closed = false;
-  pWindowRes->window = TSWINDOW_INITIALIZER;
+  pWindowRes->closed = false;
+  pWindowRes->skey = TSKEY_INITIAL_VAL;
 }
 
 /**
@@ -264,8 +268,8 @@ void clearTimeWindowResBuf(SQueryRuntimeEnv *pRuntimeEnv, SWindowResult *pWindow
  */
 void copyTimeWindowResBuf(SQueryRuntimeEnv *pRuntimeEnv, SWindowResult *dst, const SWindowResult *src) {
   dst->numOfRows = src->numOfRows;
-  dst->window = src->window;
-  dst->status = src->status;
+  dst->skey   = src->skey;
+  dst->closed = src->closed;
   
   int32_t nOutputCols = pRuntimeEnv->pQuery->numOfOutput;
   
diff --git a/src/query/src/sql.c b/src/query/src/sql.c
index 75ef2f3218..f3f55791b0 100644
--- a/src/query/src/sql.c
+++ b/src/query/src/sql.c
@@ -99,7 +99,7 @@
 #define YYCODETYPE unsigned short int
 #define YYNOCODE 274
 #define YYACTIONTYPE unsigned short int
-#define ParseTOKENTYPE SSQLToken
+#define ParseTOKENTYPE SStrToken
 typedef union {
   int yyinit;
   ParseTOKENTYPE yy0;
@@ -488,7 +488,7 @@ static const YYCODETYPE yyFallback[] = {
     0,  /*    QUERIES => nothing */
     0,  /* CONNECTIONS => nothing */
     0,  /*    STREAMS => nothing */
-    0,  /*    CONFIGS => nothing */
+    0,  /*  VARIABLES => nothing */
     0,  /*     SCORES => nothing */
     0,  /*     GRANTS => nothing */
     0,  /*     VNODES => nothing */
@@ -781,7 +781,7 @@ static const char *const yyTokenName[] = {
   /*   51 */ "QUERIES",
   /*   52 */ "CONNECTIONS",
   /*   53 */ "STREAMS",
-  /*   54 */ "CONFIGS",
+  /*   54 */ "VARIABLES",
   /*   55 */ "SCORES",
   /*   56 */ "GRANTS",
   /*   57 */ "VNODES",
@@ -1017,7 +1017,7 @@ static const char *const yyRuleName[] = {
  /*   7 */ "cmd ::= SHOW QUERIES",
  /*   8 */ "cmd ::= SHOW CONNECTIONS",
  /*   9 */ "cmd ::= SHOW STREAMS",
- /*  10 */ "cmd ::= SHOW CONFIGS",
+ /*  10 */ "cmd ::= SHOW VARIABLES",
  /*  11 */ "cmd ::= SHOW SCORES",
  /*  12 */ "cmd ::= SHOW GRANTS",
  /*  13 */ "cmd ::= SHOW VNODES",
@@ -1702,7 +1702,7 @@ static const struct {
   {  209,   -2 }, /* (7) cmd ::= SHOW QUERIES */
   {  209,   -2 }, /* (8) cmd ::= SHOW CONNECTIONS */
   {  209,   -2 }, /* (9) cmd ::= SHOW STREAMS */
-  {  209,   -2 }, /* (10) cmd ::= SHOW CONFIGS */
+  {  209,   -2 }, /* (10) cmd ::= SHOW VARIABLES */
   {  209,   -2 }, /* (11) cmd ::= SHOW SCORES */
   {  209,   -2 }, /* (12) cmd ::= SHOW GRANTS */
   {  209,   -2 }, /* (13) cmd ::= SHOW VNODES */
@@ -2029,8 +2029,8 @@ static void yy_reduce(
       case 9: /* cmd ::= SHOW STREAMS */
 { setShowOptions(pInfo, TSDB_MGMT_TABLE_STREAMS, 0, 0);  }
         break;
-      case 10: /* cmd ::= SHOW CONFIGS */
-{ setShowOptions(pInfo, TSDB_MGMT_TABLE_CONFIGS, 0, 0);  }
+      case 10: /* cmd ::= SHOW VARIABLES */
+{ setShowOptions(pInfo, TSDB_MGMT_TABLE_VARIABLES, 0, 0);  }
         break;
       case 11: /* cmd ::= SHOW SCORES */
 { setShowOptions(pInfo, TSDB_MGMT_TABLE_SCORES, 0, 0);   }
@@ -2074,21 +2074,21 @@ static void yy_reduce(
         break;
       case 22: /* cmd ::= SHOW dbPrefix STABLES LIKE ids */
 {
-    SSQLToken token;
+    SStrToken token;
     setDBName(&token, &yymsp[-3].minor.yy0);
     setShowOptions(pInfo, TSDB_MGMT_TABLE_METRIC, &token, &yymsp[0].minor.yy0);
 }
         break;
       case 23: /* cmd ::= SHOW dbPrefix VGROUPS */
 {
-    SSQLToken token;
+    SStrToken token;
     setDBName(&token, &yymsp[-1].minor.yy0);
     setShowOptions(pInfo, TSDB_MGMT_TABLE_VGROUP, &token, 0);
 }
         break;
       case 24: /* cmd ::= SHOW dbPrefix VGROUPS ids */
 {
-    SSQLToken token;
+    SStrToken token;
     setDBName(&token, &yymsp[-2].minor.yy0);    
     setShowOptions(pInfo, TSDB_MGMT_TABLE_VGROUP, &token, &yymsp[0].minor.yy0);
 }
@@ -2139,7 +2139,7 @@ static void yy_reduce(
 { setDCLSQLElems(pInfo, TSDB_SQL_CFG_LOCAL, 2, &yymsp[-1].minor.yy0, &yymsp[0].minor.yy0);          }
         break;
       case 38: /* cmd ::= ALTER DATABASE ids alter_db_optr */
-{ SSQLToken t = {0};  setCreateDBSQL(pInfo, TSDB_SQL_ALTER_DB, &yymsp[-1].minor.yy0, &yymsp[0].minor.yy268, &t);}
+{ SStrToken t = {0};  setCreateDBSQL(pInfo, TSDB_SQL_ALTER_DB, &yymsp[-1].minor.yy0, &yymsp[0].minor.yy268, &t);}
         break;
       case 39: /* cmd ::= ALTER ACCOUNT ids acct_optr */
 { setCreateAcctSQL(pInfo, TSDB_SQL_ALTER_ACCT, &yymsp[-1].minor.yy0, NULL, &yymsp[0].minor.yy149);}
@@ -2277,6 +2277,7 @@ static void yy_reduce(
   yymsp[-1].minor.yy268 = yylhsminor.yy268;
         break;
       case 95: /* db_optr ::= db_optr fsync */
+      case 107: /* alter_db_optr ::= alter_db_optr fsync */ yytestcase(yyruleno==107);
 { yylhsminor.yy268 = yymsp[-1].minor.yy268; yylhsminor.yy268.fsyncPeriod = strtol(yymsp[0].minor.yy0.z, NULL, 10); }
   yymsp[-1].minor.yy268 = yylhsminor.yy268;
         break;
@@ -2297,10 +2298,6 @@ static void yy_reduce(
       case 99: /* alter_db_optr ::= */
 { setDefaultCreateDbOption(&yymsp[1].minor.yy268);}
         break;
-      case 107: /* alter_db_optr ::= alter_db_optr fsync */
-{ yylhsminor.yy268 = yymsp[-1].minor.yy268; yylhsminor.yy268.fsyncPeriod = strtol(yymsp[0].minor.yy0.z, NULL, 10); }
-  yymsp[-1].minor.yy268 = yylhsminor.yy268;
-        break;
       case 108: /* typename ::= ids */
 { 
   yymsp[0].minor.yy0.type = 0;
diff --git a/src/query/tests/tsBufTest.cpp b/src/query/tests/tsBufTest.cpp
index f8738eec9c..b78c5314f2 100644
--- a/src/query/tests/tsBufTest.cpp
+++ b/src/query/tests/tsBufTest.cpp
@@ -32,14 +32,16 @@ void simpleTest() {
 
   // write 10 ts points
   int32_t num = 10;
-  int64_t tag = 1;
+  tVariant t = {0};
+  t.nType = TSDB_DATA_TYPE_BIGINT;
+  t.i64Key = 1;
 
   int64_t* list = createTsList(10, 10000000, 30);
-  tsBufAppend(pTSBuf, 0, tag, (const char*)list, num * sizeof(int64_t));
+  tsBufAppend(pTSBuf, 0, &t, (const char*)list, num * sizeof(int64_t));
   EXPECT_EQ(pTSBuf->tsOrder, TSDB_ORDER_ASC);
 
   EXPECT_EQ(pTSBuf->tsData.len, sizeof(int64_t) * num);
-  EXPECT_EQ(pTSBuf->block.tag, tag);
+  EXPECT_EQ(tVariantCompare(&pTSBuf->block.tag, &t), 0);
   EXPECT_EQ(pTSBuf->numOfVnodes, 1);
 
   tsBufFlush(pTSBuf);
@@ -57,14 +59,16 @@ void largeTSTest() {
 
   // write 10 ts points
   int32_t num = 1000000;
-  int64_t tag = 1;
+  tVariant t = {0};
+  t.nType = TSDB_DATA_TYPE_BIGINT;
+  t.i64Key = 1;
 
   int64_t* list = createTsList(num, 10000000, 30);
-  tsBufAppend(pTSBuf, 0, tag, (const char*)list, num * sizeof(int64_t));
+  tsBufAppend(pTSBuf, 0, &t, (const char*)list, num * sizeof(int64_t));
 
   // the data has been flush to disk, no data in cache
   EXPECT_EQ(pTSBuf->tsData.len, 0);
-  EXPECT_EQ(pTSBuf->block.tag, tag);
+  EXPECT_EQ(tVariantCompare(&pTSBuf->block.tag, &t), 0);
   EXPECT_EQ(pTSBuf->numOfVnodes, 1);
   EXPECT_EQ(pTSBuf->tsOrder, TSDB_ORDER_ASC);
 
@@ -80,14 +84,18 @@ void multiTagsTest() {
   STSBuf* pTSBuf = tsBufCreate(true, TSDB_ORDER_ASC);
 
   int32_t num = 10000;
-  int64_t tag = 1;
+  tVariant t = {0};
+  t.nType = TSDB_DATA_TYPE_BIGINT;
+
   int64_t start = 10000000;
   int32_t numOfTags = 50;
   int32_t step = 30;
 
   for (int32_t i = 0; i < numOfTags; ++i) {
     int64_t* list = createTsList(num, start, step);
-    tsBufAppend(pTSBuf, 0, i, (const char*)list, num * sizeof(int64_t));
+    t.i64Key = i;
+
+    tsBufAppend(pTSBuf, 0, &t, (const char*)list, num * sizeof(int64_t));
     free(list);
 
     start += step * num;
@@ -96,7 +104,7 @@ void multiTagsTest() {
   EXPECT_EQ(pTSBuf->tsOrder, TSDB_ORDER_ASC);
   EXPECT_EQ(pTSBuf->tsData.len, num * sizeof(int64_t));
 
-  EXPECT_EQ(pTSBuf->block.tag, numOfTags - 1);
+  EXPECT_EQ(pTSBuf->block.tag.i64Key, numOfTags - 1);
   EXPECT_EQ(pTSBuf->numOfVnodes, 1);
 
   tsBufFlush(pTSBuf);
@@ -118,9 +126,14 @@ void multiVnodeTagsTest() {
   for (int32_t j = 0; j < 20; ++j) {
     // vnodeId:0
     start = 10000000;
+    tVariant t = {0};
+    t.nType = TSDB_DATA_TYPE_BIGINT;
+
     for (int32_t i = 0; i < numOfTags; ++i) {
       int64_t* list = createTsList(num, start, step);
-      tsBufAppend(pTSBuf, j, i, (const char*)list, num * sizeof(int64_t));
+      t.i64Key = i;
+
+      tsBufAppend(pTSBuf, j, &t, (const char*)list, num * sizeof(int64_t));
       free(list);
 
       start += step * num;
@@ -131,11 +144,11 @@ void multiVnodeTagsTest() {
 
   EXPECT_EQ(pTSBuf->tsOrder, TSDB_ORDER_ASC);
   EXPECT_EQ(pTSBuf->tsData.len, num * sizeof(int64_t));
-  EXPECT_EQ(pTSBuf->block.tag, numOfTags - 1);
+  EXPECT_EQ(pTSBuf->block.tag.i64Key, numOfTags - 1);
 
   EXPECT_EQ(pTSBuf->tsData.len, num * sizeof(int64_t));
 
-  EXPECT_EQ(pTSBuf->block.tag, numOfTags - 1);
+  EXPECT_EQ(pTSBuf->block.tag.i64Key, numOfTags - 1);
 
   tsBufFlush(pTSBuf);
   EXPECT_EQ(pTSBuf->tsData.len, 0);
@@ -157,9 +170,14 @@ void loadDataTest() {
   for (int32_t j = 0; j < numOfVnode; ++j) {
     // vnodeId:0
     int64_t start = 10000000;
+    tVariant t = {0};
+    t.nType = TSDB_DATA_TYPE_BIGINT;
+
     for (int32_t i = 0; i < numOfTags; ++i) {
       int64_t* list = createTsList(num, start, step);
-      tsBufAppend(pTSBuf, j, i, (const char*)list, num * sizeof(int64_t));
+      t.i64Key = i;
+
+      tsBufAppend(pTSBuf, j, &t, (const char*)list, num * sizeof(int64_t));
       printf("%d - %" PRIu64 "\n", i, list[0]);
 
       free(list);
@@ -172,11 +190,11 @@ void loadDataTest() {
   EXPECT_EQ(pTSBuf->tsOrder, TSDB_ORDER_ASC);
 
   EXPECT_EQ(pTSBuf->tsData.len, num * sizeof(int64_t));
-  EXPECT_EQ(pTSBuf->block.tag, numOfTags - 1);
+  EXPECT_EQ(pTSBuf->block.tag.i64Key, numOfTags - 1);
 
   EXPECT_EQ(pTSBuf->tsData.len, num * sizeof(int64_t));
 
-  EXPECT_EQ(pTSBuf->block.tag, numOfTags - 1);
+  EXPECT_EQ(pTSBuf->block.tag.i64Key, numOfTags - 1);
 
   tsBufFlush(pTSBuf);
   EXPECT_EQ(pTSBuf->tsData.len, 0);
@@ -230,16 +248,21 @@ void TSTraverse() {
   for (int32_t j = 0; j < numOfVnode; ++j) {
     // vnodeId:0
     int64_t start = 10000000;
+    tVariant t = {0};
+    t.nType = TSDB_DATA_TYPE_BIGINT;
+
     for (int32_t i = 0; i < numOfTags; ++i) {
       int64_t* list = createTsList(num, start, step);
-      tsBufAppend(pTSBuf, j, i, (const char*)list, num * sizeof(int64_t));
+      t.i64Key = i;
+
+      tsBufAppend(pTSBuf, j, &t, (const char*)list, num * sizeof(int64_t));
       printf("%d - %d - %" PRIu64 ", %" PRIu64 "\n", j, i, list[0], list[num - 1]);
 
       free(list);
       start += step * num;
 
       list = createTsList(num, start, step);
-      tsBufAppend(pTSBuf, j, i, (const char*)list, num * sizeof(int64_t));
+      tsBufAppend(pTSBuf, j, &t, (const char*)list, num * sizeof(int64_t));
       printf("%d - %d - %" PRIu64 ", %" PRIu64 "\n", j, i, list[0], list[num - 1]);
       free(list);
 
@@ -272,12 +295,16 @@ void TSTraverse() {
   int32_t startVnode = 1;
   int32_t startTag = 2;
 
-  tsBufGetElemStartPos(pTSBuf, startVnode, startTag);
+  tVariant t = {0};
+  t.nType = TSDB_DATA_TYPE_BIGINT;
+  t.i64Key = startTag;
+
+  tsBufGetElemStartPos(pTSBuf, startVnode, &t);
 
   int32_t totalOutput = 10;
   while (1) {
     STSElem elem = tsBufGetElem(pTSBuf);
-    printf("%d-%" PRIu64 "-%" PRIu64 "\n", elem.vnode, elem.tag, elem.ts);
+    printf("%d-%" PRIu64 "-%" PRIu64 "\n", elem.vnode, elem.tag.i64Key, elem.ts);
 
     if (!tsBufNextPos(pTSBuf)) {
       break;
@@ -286,7 +313,9 @@ void TSTraverse() {
     if (--totalOutput <= 0) {
       totalOutput = 10;
 
-      tsBufGetElemStartPos(pTSBuf, startVnode, --startTag);
+      startTag -= 1;
+      t.i64Key = startTag;
+      tsBufGetElemStartPos(pTSBuf, startVnode, &t);
 
       if (startTag == 0) {
         startVnode -= 1;
@@ -316,13 +345,14 @@ void TSTraverse() {
 
   startVnode = 1;
   startTag = 2;
+  t.i64Key = startTag;
 
-  tsBufGetElemStartPos(pTSBuf, startVnode, startTag);
+  tsBufGetElemStartPos(pTSBuf, startVnode, &t);
 
   totalOutput = 10;
   while (1) {
     STSElem elem = tsBufGetElem(pTSBuf);
-    printf("%d-%" PRIu64 "-%" PRIu64 "\n", elem.vnode, elem.tag, elem.ts);
+    printf("%d-%" PRIu64 "-%" PRIu64 "\n", elem.vnode, elem.tag.i64Key, elem.ts);
 
     if (!tsBufNextPos(pTSBuf)) {
       break;
@@ -331,7 +361,9 @@ void TSTraverse() {
     if (--totalOutput <= 0) {
       totalOutput = 10;
 
-      tsBufGetElemStartPos(pTSBuf, startVnode, --startTag);
+      startTag -= 1;
+      t.i64Key = startTag;
+      tsBufGetElemStartPos(pTSBuf, startVnode, &t);
 
       if (startTag < 0) {
         startVnode -= 1;
@@ -375,12 +407,17 @@ void mergeDiffVnodeBufferTest() {
   int32_t num = 1000;
   int32_t numOfTags = 10;
 
+  tVariant t = {0};
+  t.nType = TSDB_DATA_TYPE_BIGINT;
+
   // vnodeId:0
   int64_t start = 10000000;
   for (int32_t i = 0; i < numOfTags; ++i) {
     int64_t* list = createTsList(num, start, step);
-    tsBufAppend(pTSBuf1, 0, i, (const char*)list, num * sizeof(int64_t));
-    tsBufAppend(pTSBuf2, 0, i, (const char*)list, num * sizeof(int64_t));
+    t.i64Key = i;
+
+    tsBufAppend(pTSBuf1, 0, &t, (const char*)list, num * sizeof(int64_t));
+    tsBufAppend(pTSBuf2, 0, &t, (const char*)list, num * sizeof(int64_t));
 
     free(list);
 
@@ -403,6 +440,9 @@ void mergeIdenticalVnodeBufferTest() {
   STSBuf* pTSBuf1 = tsBufCreate(true, TSDB_ORDER_ASC);
   STSBuf* pTSBuf2 = tsBufCreate(true, TSDB_ORDER_ASC);
 
+  tVariant t = {0};
+  t.nType = TSDB_DATA_TYPE_BIGINT;
+
   int32_t step = 30;
   int32_t num = 1000;
   int32_t numOfTags = 10;
@@ -411,17 +451,21 @@ void mergeIdenticalVnodeBufferTest() {
   int64_t start = 10000000;
   for (int32_t i = 0; i < numOfTags; ++i) {
     int64_t* list = createTsList(num, start, step);
+    t.i64Key = i;
 
-    tsBufAppend(pTSBuf1, 12, i, (const char*)list, num * sizeof(int64_t));
+    tsBufAppend(pTSBuf1, 12, &t, (const char*)list, num * sizeof(int64_t));
     free(list);
 
     start += step * num;
   }
 
+
+
   for (int32_t i = numOfTags; i < numOfTags * 2; ++i) {
     int64_t* list = createTsList(num, start, step);
 
-    tsBufAppend(pTSBuf2, 77, i, (const char*)list, num * sizeof(int64_t));
+    t.i64Key = i;
+    tsBufAppend(pTSBuf2, 77, &t, (const char*)list, num * sizeof(int64_t));
     free(list);
 
     start += step * num;
@@ -438,7 +482,7 @@ void mergeIdenticalVnodeBufferTest() {
     STSElem elem = tsBufGetElem(pTSBuf1);
     EXPECT_EQ(elem.vnode, 12);
 
-    printf("%d-%" PRIu64 "-%" PRIu64 "\n", elem.vnode, elem.tag, elem.ts);
+    printf("%d-%" PRIu64 "-%" PRIu64 "\n", elem.vnode, elem.tag.i64Key, elem.ts);
   }
 
   tsBufDestroy(pTSBuf1);
@@ -446,6 +490,8 @@ void mergeIdenticalVnodeBufferTest() {
 }
 }  // namespace
 
+
+//TODO add binary tag value test case
 TEST(testCase, tsBufTest) {
   simpleTest();
   largeTSTest();
@@ -453,7 +499,7 @@ TEST(testCase, tsBufTest) {
   multiVnodeTagsTest();
   loadDataTest();
   invalidFileTest();
-  //  randomIncTsTest();
+//    randomIncTsTest();
   TSTraverse();
   mergeDiffVnodeBufferTest();
   mergeIdenticalVnodeBufferTest();
diff --git a/src/query/tests/unitTest.cpp b/src/query/tests/unitTest.cpp
index b59e0783a2..b6e1170d0e 100644
--- a/src/query/tests/unitTest.cpp
+++ b/src/query/tests/unitTest.cpp
@@ -16,7 +16,7 @@
 
 namespace {
 int32_t testValidateName(char* name) {
-  SSQLToken token = {0};
+  SStrToken token = {0};
   token.z = name;
   token.n = strlen(name);
   token.type = 0;
@@ -720,8 +720,8 @@ TEST(testCase, tGetToken_Test) {
   EXPECT_FALSE(type == TK_HEX);
 }
 
-static SSQLToken createStrToken(char* s) {
-  SSQLToken t = {0};//.type = TK_STRING, .z = s, .n = strlen(s)};
+static SStrToken createStrToken(char* s) {
+  SStrToken t = {0};//.type = TK_STRING, .z = s, .n = strlen(s)};
   t.type = TK_STRING;
   t.z = s;
   t.n = strlen(s);
@@ -730,7 +730,7 @@ static SSQLToken createStrToken(char* s) {
 }
 
 TEST(testCase, isValidNumber_test) {
-  SSQLToken t1 = createStrToken("123abc");
+  SStrToken t1 = createStrToken("123abc");
 
   EXPECT_EQ(isValidNumber(&t1), TK_ILLEGAL);
 
diff --git a/src/sync/src/tarbitrator.c b/src/sync/src/tarbitrator.c
index 96e3392cc5..b704b1ecae 100644
--- a/src/sync/src/tarbitrator.c
+++ b/src/sync/src/tarbitrator.c
@@ -99,9 +99,7 @@ int main(int argc, char *argv[]) {
 
   sInfo("TAOS arbitrator: %s:%d is running", tsNodeFqdn, tsArbitratorPort);
 
-  for (int res = tsem_wait(&tsArbSem); res != 0; res = tsem_wait(&tsArbSem)) {
-    if (res != EINTR) break;
-  }
+  tsem_wait(&tsArbSem);
 
   taosCloseTcpThreadPool(tsArbTcpPool);
   sInfo("TAOS arbitrator is shut down\n");
diff --git a/src/tsdb/src/tsdbRead.c b/src/tsdb/src/tsdbRead.c
index ac3a6dac07..f8ff25ddab 100644
--- a/src/tsdb/src/tsdbRead.c
+++ b/src/tsdb/src/tsdbRead.c
@@ -28,6 +28,14 @@
 #define ASCENDING_TRAVERSE(o)   (o == TSDB_ORDER_ASC)
 #define QH_GET_NUM_OF_COLS(handle) ((size_t)(taosArrayGetSize((handle)->pColumns)))
 
+#define GET_FILE_DATA_BLOCK_INFO(_checkInfo, _block)                                   \
+  ((SDataBlockInfo){.window = {.skey = (_block)->keyFirst, .ekey = (_block)->keyLast}, \
+                    .numOfCols = (_block)->numOfCols,                                  \
+                    .rows = (_block)->numOfRows,                                       \
+                    .tid = (_checkInfo)->tableId.tid,                                  \
+                    .uid = (_checkInfo)->tableId.uid})
+
+
 enum {
   TSDB_QUERY_TYPE_ALL      = 1,
   TSDB_QUERY_TYPE_LAST     = 2,
@@ -119,7 +127,14 @@ typedef struct STsdbQueryHandle {
   SIOCostSummary cost;
 } STsdbQueryHandle;
 
-static void    changeQueryHandleForLastrowQuery(TsdbQueryHandleT pqHandle);
+typedef struct STableGroupSupporter {
+  int32_t    numOfCols;
+  SColIndex* pCols;
+  STSchema*  pTagSchema;
+} STableGroupSupporter;
+
+static STimeWindow changeTableGroupByLastrow(STableGroupInfo *groupList);
+
 static void    changeQueryHandleForInterpQuery(TsdbQueryHandleT pHandle);
 static void    doMergeTwoLevelData(STsdbQueryHandle* pQueryHandle, STableCheckInfo* pCheckInfo, SCompBlock* pBlock);
 static int32_t binarySearchForKey(char* pValue, int num, TSKEY key, int order);
@@ -242,10 +257,7 @@ TsdbQueryHandleT* tsdbQueryTables(TSDB_REPO_T* tsdb, STsdbQueryCond* pCond, STab
     for (int32_t j = 0; j < gsize; ++j) {
       STableKeyInfo* pKeyInfo = (STableKeyInfo*) taosArrayGet(group, j);
 
-      STableCheckInfo info = {
-          .lastKey = pKeyInfo->lastKey,
-          .pTableObj = pKeyInfo->pTable,
-      };
+      STableCheckInfo info = { .lastKey = pKeyInfo->lastKey, .pTableObj = pKeyInfo->pTable };
       info.tableId = ((STable*)(pKeyInfo->pTable))->tableId;
 
       assert(info.pTableObj != NULL && (info.pTableObj->type == TSDB_NORMAL_TABLE ||
@@ -283,12 +295,9 @@ out_of_memory:
 }
 
 TsdbQueryHandleT tsdbQueryLastRow(TSDB_REPO_T *tsdb, STsdbQueryCond *pCond, STableGroupInfo *groupList, void* qinfo) {
+  pCond->order = TSDB_ORDER_ASC;
+  pCond->twindow = changeTableGroupByLastrow(groupList);
   STsdbQueryHandle *pQueryHandle = (STsdbQueryHandle*) tsdbQueryTables(tsdb, pCond, groupList, qinfo);
-  if (pQueryHandle != NULL) {
-    pQueryHandle->type = TSDB_QUERY_TYPE_LAST;
-    pQueryHandle->order = TSDB_ORDER_DESC;
-    changeQueryHandleForLastrowQuery(pQueryHandle);
-  }
   return pQueryHandle;
 }
 
@@ -393,7 +402,7 @@ static bool initTableMemIterator(STsdbQueryHandle* pHandle, STableCheckInfo* pCh
 
     SDataRow row = *(SDataRow *)SL_GET_NODE_DATA(node);
     TSKEY key = dataRowKey(row);  // first timestamp in buffer
-    tsdbDebug("%p uid:%" PRId64 ", tid:%d check data in mem from skey:%" PRId64 ", order:%d, ts range in buf:%" PRId64
+    tsdbDebug("%p uid:%" PRId64 ", tid:%d check data in imem from skey:%" PRId64 ", order:%d, ts range in buf:%" PRId64
               "-%" PRId64 ", lastKey:%" PRId64 ", %p",
               pHandle, pCheckInfo->tableId.uid, pCheckInfo->tableId.tid, key, order, pIMem->keyFirst, pIMem->keyLast,
               pCheckInfo->lastKey, pHandle->qinfo);
@@ -416,7 +425,7 @@ static void destroyTableMemIterator(STableCheckInfo* pCheckInfo) {
   tSkipListDestroyIter(pCheckInfo->iiter);
 }
 
-SDataRow getSDataRowInTableMem(STableCheckInfo* pCheckInfo, int32_t order) {
+static SDataRow getSDataRowInTableMem(STableCheckInfo* pCheckInfo, int32_t order) {
   SDataRow rmem = NULL, rimem = NULL;
   if (pCheckInfo->iter) {
     SSkipListNode* node = tSkipListIterGet(pCheckInfo->iter);
@@ -432,47 +441,46 @@ SDataRow getSDataRowInTableMem(STableCheckInfo* pCheckInfo, int32_t order) {
     }
   }
 
-  if (rmem != NULL && rimem != NULL) {
-    TSKEY r1 = dataRowKey(rmem);
-    TSKEY r2 = dataRowKey(rimem);
-
-    if (r1 == r2) { // data ts are duplicated, ignore the data in mem
-      tSkipListIterNext(pCheckInfo->iter);
-      pCheckInfo->chosen = 1;
-      return rimem;
-    } else {
-      if (ASCENDING_TRAVERSE(order)) {
-        if (r1 < r2) {
-          pCheckInfo->chosen = 0;
-          return rmem;
-        } else {
-          pCheckInfo->chosen = 1;
-          return rimem;
-        }
-      } else {
-        if (r1 < r2) {
-          pCheckInfo->chosen = 1;
-          return rimem;
-        } else {
-          pCheckInfo->chosen = 0;
-          return rmem;
-        }
-      }
-    }
+  if (rmem == NULL && rimem == NULL) {
+    return NULL;
   }
 
-  // at least one (rmem or rimem) is absent here
-  if (rmem != NULL) {
+  if (rmem != NULL && rimem == NULL) {
     pCheckInfo->chosen = 0;
     return rmem;
   }
 
-  if (rimem != NULL) {
+  if (rmem == NULL && rimem != NULL) {
     pCheckInfo->chosen = 1;
     return rimem;
   }
 
-  return NULL;
+  TSKEY r1 = dataRowKey(rmem);
+  TSKEY r2 = dataRowKey(rimem);
+
+  if (r1 == r2) { // data ts are duplicated, ignore the data in mem
+    tSkipListIterNext(pCheckInfo->iter);
+    pCheckInfo->chosen = 1;
+    return rimem;
+  } else {
+    if (ASCENDING_TRAVERSE(order)) {
+      if (r1 < r2) {
+        pCheckInfo->chosen = 0;
+        return rmem;
+      } else {
+        pCheckInfo->chosen = 1;
+        return rimem;
+      }
+    } else {
+      if (r1 < r2) {
+        pCheckInfo->chosen = 1;
+        return rimem;
+      } else {
+        pCheckInfo->chosen = 0;
+        return rmem;
+      }
+    }
+  }
 }
 
 static bool moveToNextRowInMem(STableCheckInfo* pCheckInfo) {
@@ -672,14 +680,6 @@ static int32_t getFileCompInfo(STsdbQueryHandle* pQueryHandle, int32_t* numOfBlo
   return code;
 }
 
-#define GET_FILE_DATA_BLOCK_INFO(_checkInfo, _block)                                   \
-  ((SDataBlockInfo){.window = {.skey = (_block)->keyFirst, .ekey = (_block)->keyLast}, \
-                    .numOfCols = (_block)->numOfCols,                                  \
-                    .rows = (_block)->numOfRows,                                       \
-                    .tid = (_checkInfo)->tableId.tid,                                  \
-                    .uid = (_checkInfo)->tableId.uid})
-
-
 static int32_t doLoadFileDataBlock(STsdbQueryHandle* pQueryHandle, SCompBlock* pBlock, STableCheckInfo* pCheckInfo, int32_t slotIndex) {
   STsdbRepo *pRepo = pQueryHandle->pTsdb;
   int64_t    st = taosGetTimestampUs();
@@ -736,6 +736,8 @@ static int32_t handleDataMergeIfNeeded(STsdbQueryHandle* pQueryHandle, SCompBloc
   SDataRow row = getSDataRowInTableMem(pCheckInfo, pQueryHandle->order);
 
   TSKEY key = (row != NULL)? dataRowKey(row):TSKEY_INITIAL_VAL;
+  tsdbDebug("%p key in mem:%"PRId64", %p", pQueryHandle, key, pQueryHandle->qinfo);
+
   cur->pos = ASCENDING_TRAVERSE(pQueryHandle->order)? 0:(binfo.rows-1);
 
   if ((ASCENDING_TRAVERSE(pQueryHandle->order) && (key != TSKEY_INITIAL_VAL && key <= binfo.window.ekey)) ||
@@ -747,7 +749,8 @@ static int32_t handleDataMergeIfNeeded(STsdbQueryHandle* pQueryHandle, SCompBloc
       // do not load file block into buffer
       int32_t step = ASCENDING_TRAVERSE(pQueryHandle->order) ? 1 : -1;
 
-      cur->rows = tsdbReadRowsFromCache(pCheckInfo, binfo.window.skey - step, pQueryHandle->outputCapacity, &cur->win, pQueryHandle);
+      TSKEY maxKey = ASCENDING_TRAVERSE(pQueryHandle->order)? (binfo.window.skey - step):(binfo.window.ekey - step);
+      cur->rows = tsdbReadRowsFromCache(pCheckInfo, maxKey, pQueryHandle->outputCapacity, &cur->win, pQueryHandle);
       pQueryHandle->realNumOfRows = cur->rows;
 
       // update the last key value
@@ -1072,8 +1075,8 @@ static void moveDataToFront(STsdbQueryHandle* pQueryHandle, int32_t numOfRows, i
   }
 }
 
-static void getQualifiedRowsPos(STsdbQueryHandle* pQueryHandle, int32_t startPos, int32_t endPos,
-    int32_t numOfExisted, int32_t *start, int32_t *end) {
+static void getQualifiedRowsPos(STsdbQueryHandle* pQueryHandle, int32_t startPos, int32_t endPos, int32_t numOfExisted,
+                                int32_t* start, int32_t* end) {
   *start = -1;
 
   if (ASCENDING_TRAVERSE(pQueryHandle->order)) {
@@ -1162,6 +1165,11 @@ static void doMergeTwoLevelData(STsdbQueryHandle* pQueryHandle, STableCheckInfo*
     cur->mixBlock = true;
   }
 
+  tsdbDebug("%p uid:%" PRIu64",tid:%d start merge data block, file block range:%"PRIu64"-%"PRIu64" rows:%d, start:%d,"
+            "end:%d, %p",
+            pQueryHandle, pCheckInfo->tableId.uid, pCheckInfo->tableId.tid, blockInfo.window.skey, blockInfo.window.ekey,
+            blockInfo.rows, cur->pos, endPos, pQueryHandle->qinfo);
+
   // compared with the data from in-memory buffer, to generate the correct timestamp array list
   int32_t numOfRows = 0;
   int32_t pos = cur->pos;
@@ -1191,6 +1199,10 @@ static void doMergeTwoLevelData(STsdbQueryHandle* pQueryHandle, STableCheckInfo*
     moveDataToFront(pQueryHandle, numOfRows, numOfCols);
     updateInfoAfterMerge(pQueryHandle, pCheckInfo, numOfRows, pos);
     doCheckGeneratedBlockRange(pQueryHandle);
+
+    tsdbDebug("%p uid:%" PRIu64",tid:%d data block created, mixblock:%d, brange:%"PRIu64"-%"PRIu64" rows:%d, %p",
+              pQueryHandle, pCheckInfo->tableId.uid, pCheckInfo->tableId.tid, cur->mixBlock, cur->win.skey,
+              cur->win.ekey, cur->rows, pQueryHandle->qinfo);
     return;
   } else if (pCheckInfo->iter != NULL || pCheckInfo->iiter != NULL) {
     SSkipListNode* node = NULL;
@@ -1233,6 +1245,8 @@ static void doMergeTwoLevelData(STsdbQueryHandle* pQueryHandle, STableCheckInfo*
         }
 
         int32_t end = doBinarySearchKey(pCols->cols[0].pData, pCols->numOfRows, key, order);
+        assert(end != -1);
+
         if (tsArray[end] == key) { // the value of key in cache equals to the end timestamp value, ignore it
           moveToNextRowInMem(pCheckInfo);
         }
@@ -1269,6 +1283,7 @@ static void doMergeTwoLevelData(STsdbQueryHandle* pQueryHandle, STableCheckInfo*
 
         cur->win.ekey = ASCENDING_TRAVERSE(pQueryHandle->order)? tsArray[end]:tsArray[start];
         cur->lastKey  = cur->win.ekey + step;
+        cur->mixBlock = true;
       }
     }
   }
@@ -1285,7 +1300,8 @@ static void doMergeTwoLevelData(STsdbQueryHandle* pQueryHandle, STableCheckInfo*
   updateInfoAfterMerge(pQueryHandle, pCheckInfo, numOfRows, pos);
   doCheckGeneratedBlockRange(pQueryHandle);
 
-  tsdbDebug("%p uid:%" PRIu64",tid:%d data block created, brange:%"PRIu64"-%"PRIu64" rows:%d, %p", pQueryHandle, pCheckInfo->tableId.uid, pCheckInfo->tableId.tid, cur->win.skey,
+  tsdbDebug("%p uid:%" PRIu64",tid:%d data block created, mixblock:%d, brange:%"PRIu64"-%"PRIu64" rows:%d, %p",
+      pQueryHandle, pCheckInfo->tableId.uid, pCheckInfo->tableId.tid, cur->mixBlock, cur->win.skey,
       cur->win.ekey, cur->rows, pQueryHandle->qinfo);
 }
 
@@ -1658,6 +1674,128 @@ static bool doHasDataInBuffer(STsdbQueryHandle* pQueryHandle) {
   return false;
 }
 
+static void changeQueryHandleForInterpQuery(TsdbQueryHandleT pHandle) {
+  // filter the queried time stamp in the first place
+  STsdbQueryHandle* pQueryHandle = (STsdbQueryHandle*) pHandle;
+  pQueryHandle->order = TSDB_ORDER_DESC;
+
+  assert(pQueryHandle->window.skey == pQueryHandle->window.ekey);
+
+  // starts from the buffer in case of descending timestamp order check data blocks
+  // todo consider the query time window, current last_row does not apply the query time window
+  size_t numOfTables = taosArrayGetSize(pQueryHandle->pTableCheckInfo);
+
+  int32_t i = 0;
+  while(i < numOfTables) {
+    STableCheckInfo* pCheckInfo = taosArrayGet(pQueryHandle->pTableCheckInfo, i);
+    if (pQueryHandle->window.skey <= pCheckInfo->pTableObj->lastKey &&
+        pCheckInfo->pTableObj->lastKey != TSKEY_INITIAL_VAL) {
+      break;
+    }
+
+    i++;
+  }
+
+  // there are no data in all the tables
+  if (i == numOfTables) {
+    return;
+  }
+
+  STableCheckInfo info = *(STableCheckInfo*) taosArrayGet(pQueryHandle->pTableCheckInfo, i);
+  taosArrayClear(pQueryHandle->pTableCheckInfo);
+
+  info.lastKey = pQueryHandle->window.skey;
+  taosArrayPush(pQueryHandle->pTableCheckInfo, &info);
+
+  // update the query time window according to the chosen last timestamp
+  pQueryHandle->window = (STimeWindow) {info.lastKey, TSKEY_INITIAL_VAL};
+}
+
+static int tsdbReadRowsFromCache(STableCheckInfo* pCheckInfo, TSKEY maxKey, int maxRowsToRead, STimeWindow* win,
+                                 STsdbQueryHandle* pQueryHandle) {
+  int     numOfRows = 0;
+  int32_t numOfCols = (int32_t)taosArrayGetSize(pQueryHandle->pColumns);
+  win->skey = TSKEY_INITIAL_VAL;
+
+  int64_t st = taosGetTimestampUs();
+  STable* pTable = pCheckInfo->pTableObj;
+
+  do {
+    SDataRow row = getSDataRowInTableMem(pCheckInfo, pQueryHandle->order);
+    if (row == NULL) {
+      break;
+    }
+
+    TSKEY key = dataRowKey(row);
+    if ((key > maxKey && ASCENDING_TRAVERSE(pQueryHandle->order)) || (key < maxKey && !ASCENDING_TRAVERSE(pQueryHandle->order))) {
+      tsdbDebug("%p key:%"PRIu64" beyond qrange:%"PRId64" - %"PRId64", no more data in buffer", pQueryHandle, key, pQueryHandle->window.skey,
+                pQueryHandle->window.ekey);
+
+      break;
+    }
+
+    if (win->skey == INT64_MIN) {
+      win->skey = key;
+    }
+
+    win->ekey = key;
+    copyOneRowFromMem(pQueryHandle, maxRowsToRead, numOfRows, row, numOfCols, pTable);
+
+    if (++numOfRows >= maxRowsToRead) {
+      moveToNextRowInMem(pCheckInfo);
+      break;
+    }
+
+  } while(moveToNextRowInMem(pCheckInfo));
+
+  assert(numOfRows <= maxRowsToRead);
+
+  // if the buffer is not full in case of descending order query, move the data in the front of the buffer
+  if (!ASCENDING_TRAVERSE(pQueryHandle->order) && numOfRows < maxRowsToRead) {
+    int32_t emptySize = maxRowsToRead - numOfRows;
+
+    for(int32_t i = 0; i < numOfCols; ++i) {
+      SColumnInfoData* pColInfo = taosArrayGet(pQueryHandle->pColumns, i);
+      memmove((char*)pColInfo->pData, (char*)pColInfo->pData + emptySize * pColInfo->info.bytes, numOfRows * pColInfo->info.bytes);
+    }
+  }
+
+  int64_t elapsedTime = taosGetTimestampUs() - st;
+  tsdbDebug("%p build data block from cache completed, elapsed time:%"PRId64" us, numOfRows:%d, numOfCols:%d, %p", pQueryHandle,
+            elapsedTime, numOfRows, numOfCols, pQueryHandle->qinfo);
+
+  return numOfRows;
+}
+
+static int32_t getAllTableList(STable* pSuperTable, SArray* list) {
+  SSkipListIterator* iter = tSkipListCreateIter(pSuperTable->pIndex);
+  while (tSkipListIterNext(iter)) {
+    SSkipListNode* pNode = tSkipListIterGet(iter);
+
+    STable** pTable = (STable**) SL_GET_NODE_DATA((SSkipListNode*) pNode);
+
+    STableKeyInfo info = {.pTable = *pTable, .lastKey = TSKEY_INITIAL_VAL};
+    taosArrayPush(list, &info);
+  }
+
+  tSkipListDestroyIter(iter);
+  return TSDB_CODE_SUCCESS;
+}
+
+static void destroyHelper(void* param) {
+  if (param == NULL) {
+    return;
+  }
+
+
+  tQueryInfo* pInfo = (tQueryInfo*)param;
+  if (pInfo->optr != TSDB_RELATION_IN) {
+    taosTFree(pInfo->q);
+  }
+
+  free(param);
+}
+
 // handle data in cache situation
 bool tsdbNextDataBlock(TsdbQueryHandleT* pHandle) {
   STsdbQueryHandle* pQueryHandle = (STsdbQueryHandle*) pHandle;
@@ -1698,6 +1836,11 @@ bool tsdbNextDataBlock(TsdbQueryHandleT* pHandle) {
       return true;
     } else {
       STsdbQueryHandle* pSecQueryHandle = calloc(1, sizeof(STsdbQueryHandle));
+      if (pSecQueryHandle == NULL) {
+        terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
+        return false;
+      }
+
       pSecQueryHandle->order       = TSDB_ORDER_ASC;
       pSecQueryHandle->window      = (STimeWindow) {pQueryHandle->window.skey, INT64_MAX};
       pSecQueryHandle->pTsdb       = pQueryHandle->pTsdb;
@@ -1709,6 +1852,7 @@ bool tsdbNextDataBlock(TsdbQueryHandleT* pHandle) {
       pSecQueryHandle->outputCapacity = ((STsdbRepo*)pSecQueryHandle->pTsdb)->config.maxRowsPerFileBlock;
 
       if (tsdbInitReadHelper(&pSecQueryHandle->rhelper, (STsdbRepo*) pSecQueryHandle->pTsdb) != 0) {
+        terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
         free(pSecQueryHandle);
         return false;
       }
@@ -1720,6 +1864,11 @@ bool tsdbNextDataBlock(TsdbQueryHandleT* pHandle) {
 
       pSecQueryHandle->statis = calloc(numOfCols, sizeof(SDataStatis));
       pSecQueryHandle->pColumns = taosArrayInit(numOfCols, sizeof(SColumnInfoData));
+      if (pSecQueryHandle->statis == NULL || pSecQueryHandle->pColumns == NULL) {
+        terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
+        tsdbCleanupQueryHandle(pSecQueryHandle);
+        return false;
+      }
 
       for (int32_t i = 0; i < numOfCols; ++i) {
         SColumnInfoData colInfo = {{0}, 0};
@@ -1727,6 +1876,12 @@ bool tsdbNextDataBlock(TsdbQueryHandleT* pHandle) {
 
         colInfo.info = pCol->info;
         colInfo.pData = calloc(1, EXTRA_BYTES + pQueryHandle->outputCapacity * pCol->info.bytes);
+        if (colInfo.pData == NULL) {
+          terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
+          tsdbCleanupQueryHandle(pSecQueryHandle);
+          return false;
+        }
+
         taosArrayPush(pSecQueryHandle->pColumns, &colInfo);
       }
 
@@ -1794,6 +1949,7 @@ bool tsdbNextDataBlock(TsdbQueryHandleT* pHandle) {
   }
 
   if (pQueryHandle->checkFiles) {
+    // check if the query range overlaps with the file data block
     bool exists = true;
 
     int32_t code = getDataBlocksInFiles(pQueryHandle, &exists);
@@ -1822,150 +1978,48 @@ bool tsdbNextDataBlock(TsdbQueryHandleT* pHandle) {
   return ret;
 }
 
-void changeQueryHandleForLastrowQuery(TsdbQueryHandleT pqHandle) {
-  STsdbQueryHandle* pQueryHandle = (STsdbQueryHandle*) pqHandle;
-  assert(!ASCENDING_TRAVERSE(pQueryHandle->order));
-
-  // starts from the buffer in case of descending timestamp order check data blocks
+STimeWindow changeTableGroupByLastrow(STableGroupInfo *groupList) {
+  STimeWindow window = {INT64_MAX, INT64_MIN};
 
+  // NOTE: starts from the buffer in case of descending timestamp order check data blocks
   // todo consider the query time window, current last_row does not apply the query time window
-  size_t numOfTables = taosArrayGetSize(pQueryHandle->pTableCheckInfo);
+  size_t numOfGroups = taosArrayGetSize(groupList->pGroupList);
+  for(int32_t j = 0; j < numOfGroups; ++j) {
+    SArray* pGroup = taosArrayGetP(groupList->pGroupList, j);
+    TSKEY   key = TSKEY_INITIAL_VAL;
 
-  TSKEY key = TSKEY_INITIAL_VAL;
-  int32_t index = -1;
+    STableKeyInfo keyInfo = {0};
 
-  for(int32_t i = 0; i < numOfTables; ++i) {
-    STableCheckInfo* pCheckInfo = taosArrayGet(pQueryHandle->pTableCheckInfo, i);
-    if (pCheckInfo->pTableObj->lastKey > key) {
-      key = pCheckInfo->pTableObj->lastKey;
-      index = i;
+    size_t numOfTables = taosArrayGetSize(pGroup);
+    for(int32_t i = 0; i < numOfTables; ++i) {
+      STableKeyInfo* pKeyInfo = (STableKeyInfo*) taosArrayGet(pGroup, i);
+      TSKEY lastKey = ((STable*)(pKeyInfo->pTable))->lastKey;
+
+      if (key < lastKey) {
+        key = lastKey;
+
+        keyInfo.pTable  = pKeyInfo->pTable;
+        keyInfo.lastKey = key;
+        pKeyInfo->lastKey = key;
+
+        if (key < window.skey) {
+          window.skey = key;
+        }
+
+        if (key > window.ekey) {
+          window.ekey = key;
+        }
+      }
+    }
+
+    // more than one table in each group, only one table left for each group
+    if (numOfTables > 1) {
+      taosArrayClear(pGroup);
+      taosArrayPush(pGroup, &keyInfo);
     }
   }
 
-  if (index == -1) {
-    // todo add failure test cases
-    return;
-  }
-
-  // erase all other elements in array list
-  size_t size = taosArrayGetSize(pQueryHandle->pTableCheckInfo);
-  for (int32_t i = 0; i < size; ++i) {
-    if (i == index) {
-      continue;
-    }
-
-    STableCheckInfo* pTableCheckInfo = taosArrayGet(pQueryHandle->pTableCheckInfo, i);
-    tSkipListDestroyIter(pTableCheckInfo->iter);
-
-    if (pTableCheckInfo->pDataCols != NULL) {
-      taosTFree(pTableCheckInfo->pDataCols->buf);
-    }
-
-    taosTFree(pTableCheckInfo->pDataCols);
-    taosTFree(pTableCheckInfo->pCompInfo);
-  }
-
-  STableCheckInfo info = *(STableCheckInfo*) taosArrayGet(pQueryHandle->pTableCheckInfo, index);
-  taosArrayClear(pQueryHandle->pTableCheckInfo);
-
-  info.lastKey = key;
-  taosArrayPush(pQueryHandle->pTableCheckInfo, &info);
-
-  // update the query time window according to the chosen last timestamp
-  pQueryHandle->window = (STimeWindow) {key, key};
-}
-
-static void changeQueryHandleForInterpQuery(TsdbQueryHandleT pHandle) {
-  // filter the queried time stamp in the first place
-  STsdbQueryHandle* pQueryHandle = (STsdbQueryHandle*) pHandle;
-  pQueryHandle->order = TSDB_ORDER_DESC;
-
-  assert(pQueryHandle->window.skey == pQueryHandle->window.ekey);
-
-  // starts from the buffer in case of descending timestamp order check data blocks
-  // todo consider the query time window, current last_row does not apply the query time window
-  size_t numOfTables = taosArrayGetSize(pQueryHandle->pTableCheckInfo);
-
-  int32_t i = 0;
-  while(i < numOfTables) {
-    STableCheckInfo* pCheckInfo = taosArrayGet(pQueryHandle->pTableCheckInfo, i);
-    if (pQueryHandle->window.skey <= pCheckInfo->pTableObj->lastKey &&
-        pCheckInfo->pTableObj->lastKey != TSKEY_INITIAL_VAL) {
-      break;
-    }
-
-    i++;
-  }
-
-  // there are no data in all the tables
-  if (i == numOfTables) {
-    return;
-  }
-
-  STableCheckInfo info = *(STableCheckInfo*) taosArrayGet(pQueryHandle->pTableCheckInfo, i);
-  taosArrayClear(pQueryHandle->pTableCheckInfo);
-
-  info.lastKey = pQueryHandle->window.skey;
-  taosArrayPush(pQueryHandle->pTableCheckInfo, &info);
-
-  // update the query time window according to the chosen last timestamp
-  pQueryHandle->window = (STimeWindow) {info.lastKey, TSKEY_INITIAL_VAL};
-}
-
-static int tsdbReadRowsFromCache(STableCheckInfo* pCheckInfo, TSKEY maxKey, int maxRowsToRead, STimeWindow* win,
-                                 STsdbQueryHandle* pQueryHandle) {
-  int     numOfRows = 0;
-  int32_t numOfCols = (int32_t)taosArrayGetSize(pQueryHandle->pColumns);
-  win->skey = TSKEY_INITIAL_VAL;
-
-  int64_t st = taosGetTimestampUs();
-  STable* pTable = pCheckInfo->pTableObj;
-
-  do {
-    SDataRow row = getSDataRowInTableMem(pCheckInfo, pQueryHandle->order);
-    if (row == NULL) {
-      break;
-    }
-
-    TSKEY key = dataRowKey(row);
-    if ((key > maxKey && ASCENDING_TRAVERSE(pQueryHandle->order)) || (key < maxKey && !ASCENDING_TRAVERSE(pQueryHandle->order))) {
-      tsdbDebug("%p key:%"PRIu64" beyond qrange:%"PRId64" - %"PRId64", no more data in buffer", pQueryHandle, key, pQueryHandle->window.skey,
-          pQueryHandle->window.ekey);
-
-      break;
-    }
-
-    if (win->skey == INT64_MIN) {
-      win->skey = key;
-    }
-
-    win->ekey = key;
-    copyOneRowFromMem(pQueryHandle, maxRowsToRead, numOfRows, row, numOfCols, pTable);
-
-    if (++numOfRows >= maxRowsToRead) {
-      moveToNextRowInMem(pCheckInfo);
-      break;
-    }
-
-  } while(moveToNextRowInMem(pCheckInfo));
-
-  assert(numOfRows <= maxRowsToRead);
-
-  // if the buffer is not full in case of descending order query, move the data in the front of the buffer
-  if (!ASCENDING_TRAVERSE(pQueryHandle->order) && numOfRows < maxRowsToRead) {
-    int32_t emptySize = maxRowsToRead - numOfRows;
-
-    for(int32_t i = 0; i < numOfCols; ++i) {
-      SColumnInfoData* pColInfo = taosArrayGet(pQueryHandle->pColumns, i);
-      memmove((char*)pColInfo->pData, (char*)pColInfo->pData + emptySize * pColInfo->info.bytes, numOfRows * pColInfo->info.bytes);
-    }
-  }
-
-  int64_t elapsedTime = taosGetTimestampUs() - st;
-  tsdbDebug("%p build data block from cache completed, elapsed time:%"PRId64" us, numOfRows:%d, numOfCols:%d, %p", pQueryHandle,
-            elapsedTime, numOfRows, numOfCols, pQueryHandle->qinfo);
-
-  return numOfRows;
+  return window;
 }
 
 void tsdbRetrieveDataBlockInfo(TsdbQueryHandleT* pQueryHandle, SDataBlockInfo* pDataBlockInfo) {
@@ -2102,36 +2156,6 @@ SArray* tsdbRetrieveDataBlock(TsdbQueryHandleT* pQueryHandle, SArray* pIdList) {
   }
 }
 
-static int32_t getAllTableList(STable* pSuperTable, SArray* list) {
-  SSkipListIterator* iter = tSkipListCreateIter(pSuperTable->pIndex);
-  while (tSkipListIterNext(iter)) {
-    SSkipListNode* pNode = tSkipListIterGet(iter);
-
-    STable** pTable = (STable**) SL_GET_NODE_DATA((SSkipListNode*) pNode);
-
-    STableKeyInfo info = {.pTable = *pTable, .lastKey = TSKEY_INITIAL_VAL};
-    taosArrayPush(list, &info);
-  }
-
-  tSkipListDestroyIter(iter);
-  return TSDB_CODE_SUCCESS;
-}
-
-static void destroyHelper(void* param) {
-  if (param == NULL) {
-    return;
-  }
-
-
-  tQueryInfo* pInfo = (tQueryInfo*)param;
-  if (pInfo->optr != TSDB_RELATION_IN) {
-    taosTFree(pInfo->q);
-  }
-
-//  tVariantDestroy(&(pInfo->q));
-  free(param);
-}
-
 void filterPrepare(void* expr, void* param) {
   tExprNode* pExpr = (tExprNode*)expr;
   if (pExpr->_node.info != NULL) {
@@ -2158,13 +2182,7 @@ void filterPrepare(void* expr, void* param) {
   }
 }
 
-typedef struct STableGroupSupporter {
-  int32_t    numOfCols;
-  SColIndex* pCols;
-  STSchema*  pTagSchema;
-} STableGroupSupporter;
-
-int32_t tableGroupComparFn(const void *p1, const void *p2, const void *param) {
+static int32_t tableGroupComparFn(const void *p1, const void *p2, const void *param) {
   STableGroupSupporter* pTableGroupSupp = (STableGroupSupporter*) param;
   STable* pTable1 = ((STableKeyInfo*) p1)->pTable;
   STable* pTable2 = ((STableKeyInfo*) p2)->pTable;
@@ -2217,8 +2235,19 @@ int32_t tableGroupComparFn(const void *p1, const void *p2, const void *param) {
   return 0;
 }
 
-void createTableGroupImpl(SArray* pGroups, SArray* pTableList, size_t numOfTables, TSKEY skey, STableGroupSupporter* pSupp,
-    __ext_compar_fn_t compareFn) {
+static int tsdbCheckInfoCompar(const void* key1, const void* key2) {
+  if (((STableCheckInfo*)key1)->tableId.tid < ((STableCheckInfo*)key2)->tableId.tid) {
+    return -1;
+  } else if (((STableCheckInfo*)key1)->tableId.tid > ((STableCheckInfo*)key2)->tableId.tid) {
+    return 1;
+  } else {
+    ASSERT(false);
+    return 0;
+  }
+}
+
+void createTableGroupImpl(SArray* pGroups, SArray* pTableList, size_t numOfTables, TSKEY skey,
+                          STableGroupSupporter* pSupp, __ext_compar_fn_t compareFn) {
   STable* pTable = taosArrayGetP(pTableList, 0);
 
   SArray* g = taosArrayInit(16, sizeof(STableKeyInfo));
@@ -2264,6 +2293,10 @@ SArray* createTableGroup(SArray* pTableList, STSchema* pTagSchema, SColIndex* pC
 
   if (numOfOrderCols == 0 || size == 1) { // no group by tags clause or only one table
     SArray* sa = taosArrayInit(size, sizeof(STableKeyInfo));
+    if (sa == NULL) {
+      taosArrayDestroy(pTableGroup);
+      return NULL;
+    }
 
     for(int32_t i = 0; i < size; ++i) {
       STableKeyInfo *pKeyInfo = taosArrayGet(pTableList, i);
@@ -2278,20 +2311,19 @@ SArray* createTableGroup(SArray* pTableList, STSchema* pTagSchema, SColIndex* pC
     taosArrayPush(pTableGroup, &sa);
     tsdbDebug("all %" PRIzu " tables belong to one group", size);
   } else {
-    STableGroupSupporter *pSupp = (STableGroupSupporter *) calloc(1, sizeof(STableGroupSupporter));
-    pSupp->numOfCols = numOfOrderCols;
-    pSupp->pTagSchema = pTagSchema;
-    pSupp->pCols = pCols;
+    STableGroupSupporter sup = {0};
+    sup.numOfCols = numOfOrderCols;
+    sup.pTagSchema = pTagSchema;
+    sup.pCols = pCols;
 
-    taosqsort(pTableList->pData, size, sizeof(STableKeyInfo), pSupp, tableGroupComparFn);
-    createTableGroupImpl(pTableGroup, pTableList, size, skey, pSupp, tableGroupComparFn);
-    taosTFree(pSupp);
+    taosqsort(pTableList->pData, size, sizeof(STableKeyInfo), &sup, tableGroupComparFn);
+    createTableGroupImpl(pTableGroup, pTableList, size, skey, &sup, tableGroupComparFn);
   }
 
   return pTableGroup;
 }
 
-bool indexedNodeFilterFp(const void* pNode, void* param) {
+static bool indexedNodeFilterFp(const void* pNode, void* param) {
   tQueryInfo* pInfo = (tQueryInfo*) param;
 
   STable* pTable = *(STable**)(SL_GET_NODE_DATA((SSkipListNode*)pNode));
@@ -2562,7 +2594,7 @@ void tsdbCleanupQueryHandle(TsdbQueryHandleT queryHandle) {
   tsdbDestroyHelper(&pQueryHandle->rhelper);
 
   SIOCostSummary* pCost = &pQueryHandle->cost;
-  tsdbDebug("%p :io-cost summary: statis-info:%"PRId64"us, datablock:%" PRId64"us, check data:%"PRId64"us, %p",
+  tsdbDebug("%p :io-cost summary: statis-info:%"PRId64" us, datablock:%" PRId64" us, check data:%"PRId64" us, %p",
       pQueryHandle, pCost->statisInfoLoadTime, pCost->blockLoadTime, pCost->checkForNextTime, pQueryHandle->qinfo);
 
   taosTFree(pQueryHandle);
@@ -2589,14 +2621,3 @@ void tsdbDestroyTableGroup(STableGroupInfo *pGroupList) {
 
   taosArrayDestroy(pGroupList->pGroupList);
 }
-
-static int tsdbCheckInfoCompar(const void* key1, const void* key2) {
-  if (((STableCheckInfo*)key1)->tableId.tid < ((STableCheckInfo*)key2)->tableId.tid) {
-    return -1;
-  } else if (((STableCheckInfo*)key1)->tableId.tid > ((STableCheckInfo*)key2)->tableId.tid) {
-    return 1;
-  } else {
-    ASSERT(false);
-    return 0;
-  }
-}
diff --git a/src/util/inc/tcache.h b/src/util/inc/tcache.h
index 11121fcf3b..3d6f9705ee 100644
--- a/src/util/inc/tcache.h
+++ b/src/util/inc/tcache.h
@@ -103,7 +103,7 @@ SCacheObj *taosCacheInit(int32_t keyType, int64_t refreshTimeInSeconds, bool ext
  * @param keepTime      survival time in second
  * @return              cached element
  */
-void *taosCachePut(SCacheObj *pCacheObj, const void *key, size_t keyLen, const void *pData, size_t dataSize, int keepTimeInSeconds);
+void *taosCachePut(SCacheObj *pCacheObj, const void *key, size_t keyLen, const void *pData, size_t dataSize, int durationMS);
 
 /**
  * get data from cache
@@ -113,16 +113,6 @@ void *taosCachePut(SCacheObj *pCacheObj, const void *key, size_t keyLen, const v
  */
 void *taosCacheAcquireByKey(SCacheObj *pCacheObj, const void *key, size_t keyLen);
 
-/**
- * update the expire time of data in cache 
- * @param pCacheObj     cache object
- * @param key           key
- * @param keyLen        keyLen
- * @param expireTime    new expire time of data
- * @return
- */ 
-//void* taosCacheUpdateExpireTimeByName(SCacheObj *pCacheObj, void *key, size_t keyLen, uint64_t expireTime);
-
 /**
  * Add one reference count for the exist data, and assign this data for a new owner.
  * The new owner needs to invoke the taosCacheRelease when it does not need this data anymore.
diff --git a/src/util/inc/tlockfree.h b/src/util/inc/tlockfree.h
index a81f597832..e960b601ca 100644
--- a/src/util/inc/tlockfree.h
+++ b/src/util/inc/tlockfree.h
@@ -36,6 +36,14 @@ typedef void (*_ref_fn_t)(const void* pObj);
     _ref_fn_t end;                \
   } _ref_func = {.begin = (s), .end = (e)};
 
+// set the initial reference count value
+#define T_REF_INIT_VAL(x, _v)                \
+  do {                                       \
+    assert(_v >= 0);                         \
+    atomic_store_32(&((x)->_ref.val), (_v)); \
+  } while (0)
+
+// increase the reference count by 1
 #define T_REF_INC(x) (atomic_add_fetch_32(&((x)->_ref.val), 1))
 
 #define T_REF_INC_WITH_CB(x, p)                           \
diff --git a/src/util/inc/tstoken.h b/src/util/inc/tstoken.h
index c1c6f2de7a..7aeb2da6b6 100644
--- a/src/util/inc/tstoken.h
+++ b/src/util/inc/tstoken.h
@@ -28,11 +28,11 @@ extern "C" {
 #define TSQL_TBNAME_L "tbname"
 
 // used to denote the minimum unite in sql parsing
-typedef struct SSQLToken {
+typedef struct SStrToken {
   uint32_t n;
   uint32_t type;
   char *   z;
-} SSQLToken;
+} SStrToken;
 
 /**
  * tokenizer for sql string
@@ -52,7 +52,7 @@ uint32_t tSQLGetToken(char *z, uint32_t *tokenType);
  * @param ignoreTokenTypes
  * @return
  */
-SSQLToken tStrGetToken(char *str, int32_t *i, bool isPrevOptr, uint32_t numOfIgnoreToken, uint32_t *ignoreTokenTypes);
+SStrToken tStrGetToken(char *str, int32_t *i, bool isPrevOptr, uint32_t numOfIgnoreToken, uint32_t *ignoreTokenTypes);
 
 /**
  * check if it is a keyword or not
@@ -76,7 +76,7 @@ bool isKeyWord(const char *z, int32_t len);
  * @param pToken
  * @return        token type, if it is not a number, TK_ILLEGAL will return
  */
-static FORCE_INLINE int32_t isValidNumber(const SSQLToken* pToken) {
+static FORCE_INLINE int32_t isValidNumber(const SStrToken* pToken) {
   const char* z = pToken->z;
   int32_t type = TK_ILLEGAL;
 
diff --git a/src/util/src/hash.c b/src/util/src/hash.c
index 714f36f1cb..7d10545ce7 100644
--- a/src/util/src/hash.c
+++ b/src/util/src/hash.c
@@ -657,7 +657,7 @@ void taosHashTableResize(SHashObj *pHashObj) {
   }
 
   int64_t st = taosGetTimestampUs();
-  void *pNewEntryList = realloc(pHashObj->hashList, sizeof(void*) * newSize);
+  void *pNewEntryList = realloc(pHashObj->hashList, sizeof(void *) * newSize);
   if (pNewEntryList == NULL) {  // todo handle error
     //    uDebug("cache resize failed due to out of memory, capacity remain:%d", pHashObj->capacity);
     return;
diff --git a/src/util/src/tcache.c b/src/util/src/tcache.c
index bd903c8c23..dfa982b848 100644
--- a/src/util/src/tcache.c
+++ b/src/util/src/tcache.c
@@ -189,12 +189,12 @@ SCacheObj *taosCacheInit(int32_t keyType, int64_t refreshTimeInSeconds, bool ext
   return pCacheObj;
 }
 
-void *taosCachePut(SCacheObj *pCacheObj, const void *key, size_t keyLen, const void *pData, size_t dataSize, int duration) {
+void *taosCachePut(SCacheObj *pCacheObj, const void *key, size_t keyLen, const void *pData, size_t dataSize, int durationMS) {
   if (pCacheObj == NULL || pCacheObj->pHashTable == NULL || pCacheObj->deleting == 1) {
     return NULL;
   }
 
-  SCacheDataNode *pNode1 = taosCreateCacheNode(key, keyLen, pData, dataSize, duration);
+  SCacheDataNode *pNode1 = taosCreateCacheNode(key, keyLen, pData, dataSize, durationMS);
   if (pNode1 == NULL) {
     uError("cache:%s, key:%p, failed to added into cache, out of memory", pCacheObj->name, key);
     return NULL;
diff --git a/src/util/src/tcompare.c b/src/util/src/tcompare.c
index 9564588254..ba711ced8f 100644
--- a/src/util/src/tcompare.c
+++ b/src/util/src/tcompare.c
@@ -220,8 +220,14 @@ static int32_t compareStrPatternComp(const void* pLeft, const void* pRight) {
   char pattern[128] = {0};
   memcpy(pattern, varDataVal(pRight), varDataLen(pRight));
   assert(varDataLen(pRight) < 128);
-  
-  int32_t ret = patternMatch(pattern, varDataVal(pLeft), varDataLen(pLeft), &pInfo);
+
+  size_t sz = varDataLen(pLeft);
+  char *buf = malloc(sz + 1); 
+  memcpy(buf, varDataVal(pLeft), sz); 
+  buf[sz] = 0;
+
+  int32_t ret = patternMatch(pattern, buf, sz, &pInfo);
+  free(buf);
   return (ret == TSDB_PATTERN_MATCH) ? 0 : 1;
 }
 
diff --git a/src/util/src/tsched.c b/src/util/src/tsched.c
index cf7f5c10d4..f014dd0fab 100644
--- a/src/util/src/tsched.c
+++ b/src/util/src/tsched.c
@@ -123,11 +123,6 @@ void *taosProcessSchedQueue(void *param) {
 
   while (1) {
     if (tsem_wait(&pSched->fullSem) != 0) {
-      if (errno == EINTR) {
-        /* sem_wait is interrupted by interrupt, ignore and continue */
-        uDebug("wait %s fullSem was interrupted", pSched->label);
-        continue;
-      }
       uError("wait %s fullSem failed(%s)", pSched->label, strerror(errno));
     }
     if (pSched->stop) {
@@ -163,12 +158,8 @@ int taosScheduleTask(void *qhandle, SSchedMsg *pMsg) {
     return 0;
   }
 
-  while (tsem_wait(&pSched->emptySem) != 0) {
-    if (errno != EINTR) {
-      uError("wait %s emptySem failed(%s)", pSched->label, strerror(errno));
-      break;
-    }
-    uDebug("wait %s emptySem was interrupted", pSched->label);
+  if (tsem_wait(&pSched->emptySem) != 0) {
+    uError("wait %s emptySem failed(%s)", pSched->label, strerror(errno));
   }
 
   if (pthread_mutex_lock(&pSched->queueMutex) != 0)
diff --git a/src/util/src/version.c.in b/src/util/src/version.c.in
index c7aea2afb1..21c78a0eb4 100644
--- a/src/util/src/version.c.in
+++ b/src/util/src/version.c.in
@@ -1,7 +1,7 @@
-char version[12] = "${TD_VER_1}.${TD_VER_2}.${TD_VER_3}.${TD_VER_4}";
+char version[12] = "${TD_VER_NUMBER}";
 char compatible_version[12] = "${TD_VER_COMPATIBLE}";
 char gitinfo[48] = "${TD_VER_GIT}";
 char gitinfoOfInternal[48] = "${TD_VER_GIT_INTERNAL}";
 char buildinfo[64] = "Built at ${TD_VER_DATE}";
 
-void libtaos_${TD_VER_1}_${TD_VER_2}_${TD_VER_3}_${TD_VER_4}_${TD_VER_OSTYPE}_${TD_VER_CPUTYPE}_${TD_VER_VERTYPE}() {};
+void libtaos_${TD_LIB_VER_NUMBER}_${TD_VER_OSTYPE}_${TD_VER_CPUTYPE}_${TD_VER_VERTYPE}() {};
diff --git a/src/vnode/src/vnodeMain.c b/src/vnode/src/vnodeMain.c
index 176a451168..c294e86839 100644
--- a/src/vnode/src/vnodeMain.c
+++ b/src/vnode/src/vnodeMain.c
@@ -297,6 +297,11 @@ int32_t vnodeOpen(int32_t vnode, char *rootDir) {
   }
 
   pVnode->qMgmt = qOpenQueryMgmt(pVnode->vgId);
+  if (pVnode->qMgmt == NULL) {
+    vnodeCleanUp(pVnode);
+    return terrno;
+  }
+
   pVnode->events = NULL;
   pVnode->status = TAOS_VN_STATUS_READY;
   vDebug("vgId:%d, vnode is opened in %s, pVnode:%p", pVnode->vgId, rootDir, pVnode);
diff --git a/tests/script/general/parser/bug.sim b/tests/script/general/parser/bug.sim
deleted file mode 100644
index 2a46ad1fd6..0000000000
--- a/tests/script/general/parser/bug.sim
+++ /dev/null
@@ -1,43 +0,0 @@
-system sh/stop_dnodes.sh
-
-system sh/deploy.sh -n dnode1 -i 1
-system sh/cfg.sh -n dnode1 -c walLevel       -v 0
-
-system sh/cfg.sh -n dnode1 -c dDebugFlag       -v 135
-system sh/cfg.sh -n dnode1 -c mDebugFlag       -v 135
-system sh/cfg.sh -n dnode1 -c sdbDebugFlag     -v 135
-system sh/cfg.sh -n dnode1 -c rpcDebugFlag    -v 135
-system sh/cfg.sh -n dnode1 -c cDebugFlag       -v 135
-system sh/cfg.sh -n dnode1 -c monitorDebugflag -v 135
-system sh/cfg.sh -n dnode1 -c httpDebugFlag    -v 135
-system sh/cfg.sh -n dnode1 -c uDebugFlag       -v 135
-
-system sh/cfg.sh -n dnode1 -c httpCacheSessions  -v 10
-system sh/cfg.sh -n dnode1 -c httpMaxThreads     -v 10
-system sh/cfg.sh -n dnode1 -c httpEnableCompress -v 0
-
-system sh/cfg.sh -n dnode1 -c maxVnodeConnections -v 30000
-system sh/cfg.sh -n dnode1 -c maxMgmtConnections -v 30000
-system sh/cfg.sh -n dnode1 -c maxMeterConnections -v 30000
-system sh/cfg.sh -n dnode1 -c maxShellConns       -v 30000
-
-system sh/exec.sh -n dnode1 -s start
-sql connect
-
-sql create database db;
-sql use db;
-sql create table t (ts timestamp, i int);
-sql create table st1 (ts timestamp, f1 int) tags(t1 int);
-sql create table st2 (ts timestamp, f2 int) tags(t2 int);
-
-sql create table t1 using st1 tags(1);
-sql create table t2 using st2 tags(1);
-
-sql insert into t1 values(1575880055000, 1);
-sql insert into t2 values(1575880055000, 2);
-
-sql select st1.ts, st1.f1, st2.f2 from db.st1, db.st2 where st1.t1=st2.t2 and st1.ts=st2.ts
-
-system_content curl -H 'Authorization: Taosd /KfeAzX/f9na8qdtNZmtONryp201ma04bEl8LcvLUd7a8qdtNZmtONryp201ma04' -d 'select st1.ts, st1.f1, st2.f2 from db.st1, db.st2 where st1.t1=st2.t2 and st1.ts=st2.ts'  127.0.0.1:7111/restful/sql
-
-system sh/exec.sh -n dnode1 -s stop -x SIGINT
diff --git a/tests/script/general/parser/constCol.sim b/tests/script/general/parser/constCol.sim
new file mode 100644
index 0000000000..a196ba2b50
--- /dev/null
+++ b/tests/script/general/parser/constCol.sim
@@ -0,0 +1,354 @@
+system sh/stop_dnodes.sh
+
+system sh/deploy.sh -n dnode1 -i 1
+system sh/cfg.sh -n dnode1 -c walLevel       -v 0
+
+system sh/cfg.sh -n dnode1 -c dDebugFlag       -v 135
+system sh/cfg.sh -n dnode1 -c mDebugFlag       -v 135
+system sh/cfg.sh -n dnode1 -c sdbDebugFlag     -v 135
+system sh/cfg.sh -n dnode1 -c rpcDebugFlag    -v 135
+system sh/cfg.sh -n dnode1 -c cDebugFlag       -v 135
+system sh/cfg.sh -n dnode1 -c monitorDebugflag -v 135
+system sh/cfg.sh -n dnode1 -c httpDebugFlag    -v 135
+system sh/cfg.sh -n dnode1 -c uDebugFlag       -v 135
+
+system sh/cfg.sh -n dnode1 -c httpCacheSessions  -v 10
+system sh/cfg.sh -n dnode1 -c httpMaxThreads     -v 10
+system sh/cfg.sh -n dnode1 -c httpEnableCompress -v 0
+
+system sh/cfg.sh -n dnode1 -c maxVnodeConnections -v 30000
+system sh/cfg.sh -n dnode1 -c maxMgmtConnections -v 30000
+system sh/cfg.sh -n dnode1 -c maxMeterConnections -v 30000
+system sh/cfg.sh -n dnode1 -c maxShellConns       -v 30000
+
+system sh/exec.sh -n dnode1 -s start
+sql connect
+
+sql create database db;
+sql use db;
+sql create table t (ts timestamp, i int);
+sql create table st1 (ts timestamp, f1 int) tags(t1 int);
+sql create table st2 (ts timestamp, f2 int) tags(t2 int);
+
+sql create table t1 using st1 tags(1);
+sql create table t2 using st2 tags(1);
+
+sql insert into t1 values(1575880055000, 1);
+sql insert into t1 values(1575880059000, 1);
+sql insert into t1 values(1575880069000, 1);
+
+sql insert into t2 values(1575880055000, 2);
+
+sql select st1.ts, st1.f1, st2.f2 from db.st1, db.st2 where st1.t1=st2.t2 and st1.ts=st2.ts
+
+system_content curl -H 'Authorization: Taosd /KfeAzX/f9na8qdtNZmtONryp201ma04bEl8LcvLUd7a8qdtNZmtONryp201ma04' -d 'select st1.ts, st1.f1, st2.f2 from db.st1, db.st2 where st1.t1=st2.t2 and st1.ts=st2.ts'  127.0.0.1:7111/restful/sql
+
+print ==============select with user-defined columns
+sql select 'abc' as f, ts,f1 from t1
+if $rows != 3 then
+  return -1
+endi
+
+if $data00 != @abc@ then
+  return -1
+endi
+
+if $data01 != @19-12-09 16:27:35.000@ then
+  return -1
+endi
+
+if $data02 != 1 then
+  return -1
+endi
+
+sql select 'abc', ts, f1 from t1
+if $rows != 3 then
+  return -1
+endi
+
+if $data01 != @19-12-09 16:27:35.000@ then
+  return -1
+endi
+
+if $data02 != 1 then
+  return -1
+endi
+
+if $data10 != @abc@ then
+  return -1
+endi
+
+sql select 'abc' from t1
+if $rows != 3 then
+  return -1
+endi
+
+if $data00 != @abc@ then
+  return -1
+endi
+
+sql select 'abc' as f1 from t1
+if $rows != 3 then
+  return -1
+endi
+
+if $data00 != @abc@ then
+  return -1
+endi
+
+sql select 1 from t1
+if $rows != 3 then
+  return -1
+endi
+
+if $data00 != 1 then
+  return -1
+endi
+
+if $data10 != 1 then
+  return -1
+endi
+
+if $data20 != 1 then
+  return -1
+endi
+
+sql select 1 as f1 from t1
+if $rows != 3 then
+  return -1
+endi
+
+if $data00 != 1 then
+  return -1
+endi
+
+sql select 1 as f, f1 from t1
+if $rows != 3 then
+  return -1
+endi
+
+if $data00 != 1 then
+  return -1
+endi
+
+if $data01 != 1 then
+  return -1
+endi
+
+sql select 1.123 as f, f1 from t1
+if $rows != 3 then
+  return -1
+endi
+
+if $data00 != 1.123000000 then
+  print expect 1.123000000 , actual:$data00
+  return -1
+endi
+
+if $data10 != 1.123000000 then
+  print expect 1.123000000 , actual:$data10
+  return -1
+endi
+
+sql select 1, f1 from t1
+if $rows != 3 then
+  return -1
+endi
+
+if $data00 != 1 then
+  return -1
+endi
+
+if $data01 != 1 then
+  return -1
+endi
+
+if $data10 != 1 then
+  return -1
+endi
+
+sql select 1.2391, f1 from t1
+if $rows != 3 then
+  return -1
+endi
+
+if $data00 != 1.239100000 then
+  print expect 1.239100000 actual: $data00
+  return -1
+endi
+
+if $data10 != 1.239100000 then
+  print expect 1.239100000 actual: $data00
+  return -1
+endi
+
+if $data01 != 1 then
+  return -1
+endi
+
+print ===================== user-defined columns with agg functions
+sql select 1 as t, count(*) from t1
+if $rows != 1 then
+ return -1
+endi
+
+if $data00 != 1 then
+  return -1
+endi
+
+if $data01 != 3 then
+  return -1
+endi
+
+sql select 1, sum(f1) from t1
+if $rows != 1 then
+ return -1
+endi
+
+if $data00 != 1 then
+  return -1
+endi
+
+if $data01 != 3 then
+  return -1
+endi
+
+sql select 1,2,3, sum(f1)*99, 4,5,6,7,8,9,10 from t1
+if $rows != 1 then
+ return -1
+endi
+
+if $data00 != 1 then
+  return -1
+endi
+
+if $data01 != 2 then
+  return -1
+endi
+
+if $data02 != 3 then
+  return -1
+endi
+
+if $data03 != 297.000000000  then
+  print expect 297.000000000, actual:$data03
+  return -1
+endi
+
+sql select sum(f1)*avg(f1)+12, 1,2,3,4,5,6,7,8,9,10 from t1
+if $rows != 1 then
+ return -1
+endi
+
+if $data00 != 15.000000000 then
+  print expect 15.000000000 actual:$data00
+  return -1
+endi
+
+if $data01 != 1 then
+  return -1
+endi
+
+if $data02 != 2 then
+  return -1
+endi
+
+sql select 1.2987, f1, 'k' from t1 where f1=1
+if $rows != 3 then
+  return -1
+endi
+
+if $data00 != 1.298700000 then
+  print expect 1.298700000 actual:$data00
+  return -1
+endi
+
+if $data01 != 1 then
+  return -1
+endi
+
+if $data02 != @k@ then
+  return -1
+endi
+
+print ====================user-defined columns with union
+sql select f1, 'f1' from t1 union all select f1, 'f1' from t1;
+if $rows != 6 then
+  return -1
+endi
+
+if $data00 != 1 then
+  return -1
+endi
+
+if $data01 != @f1@ then
+  return -1
+endi
+
+if $data10 != 1 then
+  return -1
+endi
+
+if $data11 != @f1@ then
+  return -1
+endi
+
+print =====================udc with join
+sql select st1.ts, st1.f1, st2.f2, 'abc', 1.9827 from db.st1, db.st2 where st1.t1=st2.t2 and st1.ts=st2.ts
+if $rows != 1 then
+  return -1
+endi
+
+if $data00 != @19-12-09 16:27:35.000@ then
+  print expect @19-12-09 16:27:35.000@ actual:$data00
+  return -1
+endi
+
+if $data01 != 1 then
+  return -1
+endi
+
+if $data02 != 2 then
+  return -1
+endi
+
+if $data03 != @abc@ then
+  return -1
+endi
+
+if $data04 != 1.982700000 then
+  print expect 1.982700000 actual:$data04
+  return -1
+endi
+
+print ======================udc with interval
+sql select count(*), 'uuu' from t1 interval(1s) order by ts desc;
+if $rows != 3 then
+  return -1
+endi
+
+print ======================udc with tags
+sql select t1,'abc',tbname from st1
+if $rows != 1 then
+  return -1
+endi
+
+if $data01 != @abc@ then
+  return -1
+endi
+
+if $data02 != @t1@ then
+  return -1
+endi
+
+print ======================udc with arithmetic
+sql select 1+1 from t1
+if $rows != 3 then
+  return -1
+endi
+
+sql_error select from t1
+sql_error select abc from t1
+sql_error select abc as tu from t1
+
+system sh/exec.sh -n dnode1 -s stop -x SIGINT
diff --git a/tests/script/general/parser/fill_stb.sim b/tests/script/general/parser/fill_stb.sim
index 402b79d6b5..f0cd058352 100644
--- a/tests/script/general/parser/fill_stb.sim
+++ b/tests/script/general/parser/fill_stb.sim
@@ -133,12 +133,18 @@ endi
 if $data74 != -4.000000000 then
   return -1
 endi
+
 ## fill(value) + group by
 sql select max(c1), max(c2), max(c3), max(c4), max(c5) from $stb where ts >= $ts0 and ts <= $tsu interval(5m) fill(value, -1, -2, -3, -4, -5, -6, -7, -8) group by t1
 $val = $rowNum * 2
+print $rowNum, $val
+
 $val = $val - 1
 $val = $val * $tbNum
-if $rows != $val then
+print ==================== $val
+
+if $rows != 190 then
+  print expect 190, actual:$rows
   return -1
 endi
 if $data06 != 0 then
diff --git a/tests/script/general/parser/join.sim b/tests/script/general/parser/join.sim
index 882f561ae1..1bb0ff5448 100644
--- a/tests/script/general/parser/join.sim
+++ b/tests/script/general/parser/join.sim
@@ -330,7 +330,10 @@ sql_error select join_tb1.* from $tb1 , $tb2 where join_tb1.ts != join_tb0.ts an
 sql_error select join_tb1.* from $tb1 , $tb1 where join_tb1.ts = join_tb1.ts and join_tb1.ts >= 100000;
 sql_error select join_tb1.* from $tb1 , $tb1 where join_tb1.ts = join_tb1.ts order by ts;
 sql_error select join_tb1.* from $tb1 , $tb1 where join_tb1.ts = join_tb1.ts order by join_tb1.c7;
-
+sql_error select * from join_tb0, join_tb1
+sql_error select last_row(*) from join_tb0, join_tb1
+sql_error select last_row(*) from $tb1, $tb2 where join_tb1.ts < now
+sql_error select last_row(*) from $tb1, $tb2 where join_tb1.ts = join_tb2.ts
 
 print ==================================super table join ==============================
 # select duplicate columns
diff --git a/tests/script/general/parser/lastrow_query.sim b/tests/script/general/parser/lastrow_query.sim
index 98eb5a8d6d..7954a8d228 100644
--- a/tests/script/general/parser/lastrow_query.sim
+++ b/tests/script/general/parser/lastrow_query.sim
@@ -128,3 +128,27 @@ if $rows != 86399 then
   return -1
 endi
 
+sql select t1,t1,count(*),t1,t1 from lr_stb0 where ts>'2018-09-24 00:00:00.000' and ts<'2018-09-25 00:00:00.000' interval(1h) fill(NULL) group by t1 order by ts DESC limit 30
+if $rows != 48 then
+  return -1
+endi
+
+sql select t1,t1,count(*),t1,t1 from lr_stb0 where ts>'2018-09-24 00:00:00.000' and ts<'2018-09-25 00:00:00.000' interval(1h) fill(NULL) group by t1 order by ts DESC limit 2
+if $rows != 4 then
+  return -1
+endi
+
+sql select t1,t1,count(*),tbname,t1,t1,tbname from lr_stb0 where ts>'2018-09-24 00:00:00.000' and ts<'2018-09-25 00:00:00.000' interval(1s) fill(NULL) group by tbname, t1 order by ts desc slimit 1 soffset 1 limit 250000 offset 1
+if $rows != 86399 then
+  return -1
+endi
+
+sql select t1,t1,count(*),t1,t1 from lr_stb0 where ts>'2018-09-24 00:00:00.000' and ts<'2018-09-25 00:00:00.000' interval(1h) fill(NULL) group by t1 order by ts desc limit 1
+if $rows != 2 then
+  return -1
+endi
+
+sql select t1,t1,count(*),t1,t1 from lr_stb0 where ts>'2018-09-24 00:00:00.000' and ts<'2018-09-25 00:00:00.000' interval(1h) fill(NULL) group by t1 order by ts desc limit 25 offset 1
+if $rows != 46 then
+  return -1
+endi
diff --git a/tests/script/general/parser/nchar.sim b/tests/script/general/parser/nchar.sim
index 8d4e468f0e..bdac5ace55 100644
--- a/tests/script/general/parser/nchar.sim
+++ b/tests/script/general/parser/nchar.sim
@@ -223,6 +223,7 @@ if $rows != 2 then
 endi
 print data00 = $data00
 if $data00 != 5 then
+  print expect 5, actual: $data00
   return -1
 endi
 if $data10 != 5 then
diff --git a/tests/script/general/parser/testSuite.sim b/tests/script/general/parser/testSuite.sim
index aafba2d328..4e26d14cfd 100644
--- a/tests/script/general/parser/testSuite.sim
+++ b/tests/script/general/parser/testSuite.sim
@@ -97,7 +97,7 @@ run general/parser/topbot.sim
 sleep 2000
 run general/parser/union.sim
 sleep 2000
-run general/parser/bug.sim
+run general/parser/constCol.sim
 sleep 2000
 run general/parser/sliding.sim
 
diff --git a/tests/script/jenkins/basic.txt b/tests/script/jenkins/basic.txt
index 9baa42a8d5..40598332d9 100644
--- a/tests/script/jenkins/basic.txt
+++ b/tests/script/jenkins/basic.txt
@@ -147,7 +147,6 @@ cd ../../../debug; make
 ./test.sh -f general/parser/join.sim
 ./test.sh -f general/parser/join_multivnode.sim
 ./test.sh -f general/parser/binary_escapeCharacter.sim
-./test.sh -f general/parser/bug.sim
 ./test.sh -f general/parser/repeatAlter.sim
 ./test.sh -f general/parser/union.sim
 ./test.sh -f general/parser/topbot.sim
diff --git a/tests/script/wtest.bat b/tests/script/wtest.bat
index 1574b5013e..6cdd63b42d 100644
--- a/tests/script/wtest.bat
+++ b/tests/script/wtest.bat
@@ -6,8 +6,8 @@ echo Start TDengine Testing Case ...
 set "SCRIPT_DIR=%~dp0"
 echo SCRIPT_DIR: %SCRIPT_DIR%
 
-set "BUILD_DIR=%~dp0..\..\debug\build\bin"
-set "TSIM=%~dp0..\..\debug\build\bin\tsim"
+set "BUILD_DIR=%~dp0..\..\debug\32\build\bin"
+set "TSIM=%~dp0..\..\debug\32\build\bin\tsim"
 echo BUILD_DIR:  %BUILD_DIR%
 
 set "SIM_DIR=%~dp0..\..\sim"
@@ -47,7 +47,7 @@ echo qdebugFlag    143           >> %TAOS_CFG%
 echo udebugFlag    143           >> %TAOS_CFG%
 
 set "FILE_NAME=windows\testSuite.sim"
-set "FIRSTEP=localhost"
+set "FIRSTEP=192.168.1.182"
 if "%1" == "-f" set "FILE_NAME=%2"
 if "%1" == "-h" set "FIRSTEP=%2"
 if "%3" == "-f" set "FILE_NAME=%4"