Merge branch 'develop' into feature/TD-1925_new

2021-01-29 09:57:40 +08:00 · 2021-01-29 09:57:40 +08:00 · 942c881436
parent 0948fdcaab 9242cef879
commit 942c881436
48 changed files with 595 additions and 305 deletions
--- a/documentation20/webdocs/markdowndocs/TAOS
+++ b/documentation20/webdocs/markdowndocs/TAOS
@ -213,16 +213,19 @@ TDengine缺省的时间戳是毫秒精度，但通过修改配置参数enableMic
    如果表是通过[超级表](../super-table/)创建，更改表结构的操作只能对超级表进行。同时针对超级表的结构更改对所有通过该结构创建的表生效。对于不是通过超级表创建的表，可以直接修改表结构

 ## 超级表STable管理
+
+注意：在 2.0.15 以前的版本中，并不支持 STABLE 保留字，而是写作 TABLE。也即，在本节后文的指令说明中，CREATE、DROP、ALTER 三个指令在老版本中保留字需写作 TABLE 而不是 STABLE。
+
 - **创建超级表**

    ```mysql
-    CREATE TABLE [IF NOT EXISTS] stb_name (timestamp_field_name TIMESTAMP, field1_name data_type1 [, field2_name data_type2 ...]) TAGS (tag1_name tag_type1, tag2_name tag_type2 [, tag3_name tag_type3]);
+    CREATE STABLE [IF NOT EXISTS] stb_name (timestamp_field_name TIMESTAMP, field1_name data_type1 [, field2_name data_type2 ...]) TAGS (tag1_name tag_type1, tag2_name tag_type2 [, tag3_name tag_type3]);
    ```
-    创建STable, 与创建表的SQL语法相似，但需指定TAGS字段的名称和类型
+    创建 STable，与创建表的 SQL 语法相似，但需指定 TAGS 字段的名称和类型

    说明：

-    1) TAGS 列的数据类型不能是timestamp类型；
+    1) TAGS 列的数据类型不能是 timestamp 类型；

    2) TAGS 列名不能与其他列名相同；

@ -233,16 +236,16 @@ TDengine缺省的时间戳是毫秒精度，但通过修改配置参数enableMic
 - **删除超级表**

    ```mysql
-    DROP TABLE [IF EXISTS] stb_name;
+    DROP STABLE [IF EXISTS] stb_name;
    ```
-    删除STable会自动删除通过STable创建的子表。
+    删除 STable 会自动删除通过 STable 创建的子表。

 - **显示当前数据库下的所有超级表信息**

    ```mysql
    SHOW STABLES [LIKE tb_name_wildcar];
    ```
-    查看数据库内全部STable，及其相关信息，包括STable的名称、创建时间、列数量、标签（TAG）数量、通过该STable建表的数量。
+    查看数据库内全部 STable，及其相关信息，包括 STable 的名称、创建时间、列数量、标签（TAG）数量、通过该 STable 建表的数量。

 - **获取超级表的结构信息**

@ -253,43 +256,43 @@ TDengine缺省的时间戳是毫秒精度，但通过修改配置参数enableMic
 - **超级表增加列**

    ```mysql
-    ALTER TABLE stb_name ADD COLUMN field_name data_type;
+    ALTER STABLE stb_name ADD COLUMN field_name data_type;
    ```

 - **超级表删除列**

    ```mysql
-    ALTER TABLE stb_name DROP COLUMN field_name; 
+    ALTER STABLE stb_name DROP COLUMN field_name; 
    ```

 ## 超级表 STable 中 TAG 管理
 - **添加标签**

    ```mysql
-    ALTER TABLE stb_name ADD TAG new_tag_name tag_type;
+    ALTER STABLE stb_name ADD TAG new_tag_name tag_type;
    ```
-    为STable增加一个新的标签，并指定新标签的类型。标签总数不能超过128个，总长度不超过16k个字符。
+    为 STable 增加一个新的标签，并指定新标签的类型。标签总数不能超过 128 个，总长度不超过 16k 个字符。

 - **删除标签**

    ```mysql
-    ALTER TABLE stb_name DROP TAG tag_name;
+    ALTER STABLE stb_name DROP TAG tag_name;
    ```
    删除超级表的一个标签，从超级表删除某个标签后，该超级表下的所有子表也会自动删除该标签。

 - **修改标签名**

    ```mysql
-    ALTER TABLE stb_name CHANGE TAG old_tag_name new_tag_name;
+    ALTER STABLE stb_name CHANGE TAG old_tag_name new_tag_name;
    ```
    修改超级表的标签名，从超级表修改某个标签名后，该超级表下的所有子表也会自动更新该标签名。

 - **修改子表标签值**

    ```mysql
-    ALTER TABLE tb_name SET TAG tag_name=new_tag_value;
+    ALTER STABLE tb_name SET TAG tag_name=new_tag_value;
    ```
-    说明：除了更新标签的值的操作是针对子表进行，其他所有的标签操作（添加标签、删除标签等）均只能作用于STable，不能对单个子表操作。对STable添加标签以后，依托于该STable建立的所有表将自动增加了一个标签，所有新增标签的默认值都是NULL。
+    说明：除了更新标签的值的操作是针对子表进行，其他所有的标签操作（添加标签、删除标签等）均只能作用于 STable，不能对单个子表操作。对 STable 添加标签以后，依托于该 STable 建立的所有表将自动增加了一个标签，所有新增标签的默认值都是 NULL。

 ## 数据写入

@ -467,6 +470,17 @@ Query OK, 2 row(s) in set (0.003112s)

 注意：普通表的通配符 * 中并不包含 _标签列_。

+##### 获取标签列的去重取值
+
+从 2.0.15 版本开始，支持在超级表查询标签列时，指定 distinct 关键字，这样将返回指定标签列的所有不重复取值。
+```mysql
+SELECT DISTINCT tag_name FROM stb_name;
+```
+
+注意：目前 distinct 关键字只支持对超级表的标签列进行去重，而不能用于普通列。
+
+
+
 #### 结果集列名

 ```SELECT```子句中，如果不指定返回结果集合的列名，结果集列名称默认使用```SELECT```子句中的表达式名称作为列名称。此外，用户可使用```AS```来重命名返回结果集合中列的名称。例如：
--- a/documentation20/webdocs/markdowndocs/administrator-ch.md
+++ b/documentation20/webdocs/markdowndocs/administrator-ch.md
@ -12,7 +12,7 @@
 Memory Size = maxVgroupsPerDb * (blocks * cache + 10Mb) + numOfTables * (tagSizePerTable + 0.5Kb)
 ```

-示例：假设是4核机器，cache是缺省大小16M, blocks是缺省值6，假设有10万张表，标签总长度是256字节，则总的内存需求为：4\*(16\*6+10) + 100000*(0.25+0.5)/1000 = 499M。
+示例：假设是4核机器，cache是缺省大小16M, blocks是缺省值6，假设有10万张表，标签总长度是256字节，则总的内存需求为：4\*(16\*6+10) + 100000\*(0.25+0.5)/1000 = 499M。

 实际运行的系统往往会根据数据特点的不同，将数据存放在不同的DB里。因此做规划时，也需要考虑。

@ -35,7 +35,7 @@ TDengine相对于通用数据库，有超高的压缩比，在绝大多数场景
 Raw DataSize = numOfTables * rowSizePerTable * rowsPerTable
 ```

-示例：1000万台智能电表，每台电表每15分钟采集一次数据，每次采集的数据128字节，那么一年的原始数据量是：10000000\*128\*24\*60/15*365 = 44.8512T。TDengine大概需要消耗44.851/5=8.97024T空间。
+示例：1000万台智能电表，每台电表每15分钟采集一次数据，每次采集的数据128字节，那么一年的原始数据量是：10000000\*128\*24\*60/15\*365 = 44.8512T。TDengine大概需要消耗44.851/5=8.97024T空间。

 用户可以通过参数keep，设置数据在磁盘中的最大保存时长。为进一步减少存储成本，TDengine还提供多级存储，最冷的数据可以存放在最廉价的存储介质上，应用的访问不用做任何调整，只是读取速度降低了。

@ -181,7 +181,7 @@ taos -C  或  taos --dump-config

    客户端的输入的字符均采用操作系统当前默认的编码格式，在Linux系统上多为UTF-8，部分中文系统编码则可能是GB18030或GBK等。在docker环境中默认的编码是POSIX。在中文版Windows系统中，编码则是CP936。客户端需要确保正确设置自己所使用的字符集，即客户端运行的操作系统当前编码字符集，才能保证nchar中的数据正确转换为UCS4-LE编码格式。

-    在 Linux 中 locale 的命名规则为: <语言>_<地区>.<字符集编码> 如：zh_CN.UTF-8，zh代表中文，CN代表大陆地区，UTF-8表示字符集。字符集编码为客户端正确解析本地字符串提供编码转换的说明。Linux系统与 Mac OSX 系统可以通过设置locale来确定系统的字符编码，由于Windows使用的locale中不是POSIX标准的locale格式，因此在Windows下需要采用另一个配置参数charset来指定字符编码。在Linux 系统中也可以使用charset来指定字符编码。
+    在 Linux 中 locale 的命名规则为: <语言>\_<地区>.<字符集编码> 如：zh_CN.UTF-8，zh代表中文，CN代表大陆地区，UTF-8表示字符集。字符集编码为客户端正确解析本地字符串提供编码转换的说明。Linux系统与 Mac OSX 系统可以通过设置locale来确定系统的字符编码，由于Windows使用的locale中不是POSIX标准的locale格式，因此在Windows下需要采用另一个配置参数charset来指定字符编码。在Linux 系统中也可以使用charset来指定字符编码。

 - charset

@ -452,39 +452,39 @@ TDengine的所有可执行文件默认存放在 _/usr/local/taos/bin_ 目录下

 | 关键字列表 |             |              |            |           |
 | ---------- | ----------- | ------------ | ---------- | --------- |
-| ABLOCKS    | CONNECTION  | GT           | MINUS      | SHOW      |
-| ABORT      | CONNECTIONS | ID           | MNODES     | SLASH     |
-| ACCOUNT    | COPY        | IF           | MODULES    | SLIDING   |
-| ACCOUNTS   | COUNT       | IGNORE       | NCHAR      | SMALLINT  |
-| ADD        | CREATE      | IMMEDIATE    | NE         | SPREAD    |
-| AFTER      | CTIME       | IMPORT       | NONE       | STAR      |
-| ALL        | DATABASE    | IN           | NOT        | STATEMENT |
-| ALTER      | DATABASES   | INITIALLY    | NOTNULL    | STDDEV    |
-| AND        | DAYS        | INSERT       | NOW        | STREAM    |
-| AS         | DEFERRED    | INSTEAD      | OF         | STREAMS   |
-| ASC        | DELIMITERS  | INTEGER      | OFFSET     | STRING    |
-| ATTACH     | DESC        | INTERVAL     | OR         | SUM       |
-| AVG        | DESCRIBE    | INTO         | ORDER      | TABLE     |
-| BEFORE     | DETACH      | IP           | PASS       | TABLES    |
-| BEGIN      | DIFF        | IS           | PERCENTILE | TAG       |
-| BETWEEN    | DIVIDE      | ISNULL       | PLUS       | TAGS      |
-| BIGINT     | DNODE       | JOIN         | PRAGMA     | TBLOCKS   |
-| BINARY     | DNODES      | KEEP         | PREV       | TBNAME    |
-| BITAND     | DOT         | KEY          | PRIVILEGE  | TIMES     |
-| BITNOT     | DOUBLE      | KILL         | QUERIES    | TIMESTAMP |
-| BITOR      | DROP        | LAST         | QUERY      | TINYINT   |
-| BOOL       | EACH        | LE           | RAISE      | TOP       |
-| BOTTOM     | END         | LEASTSQUARES | REM        | TRIGGER   |
-| BY         | EQ          | LIKE         | REPLACE    | UMINUS    |
-| CACHE      | EXISTS      | LIMIT        | REPLICA    | UPLUS     |
-| CASCADE    | EXPLAIN     | LINEAR       | RESET      | USE       |
-| CHANGE     | FAIL        | LOCAL        | RESTRICT   | USER      |
-| CLOG       | FILL        | LP           | ROW        | USERS     |
-| CLUSTER    | FIRST       | LSHIFT       | ROWS       | USING     |
-| COLON      | FLOAT       | LT           | RP         | VALUES    |
-| COLUMN     | FOR         | MATCH        | RSHIFT     | VARIABLE  |
-| COMMA      | FROM        | MAX          | SCORES     | VGROUPS   |
-| COMP       | GE          | METRIC       | SELECT     | VIEW      |
-| CONCAT     | GLOB        | METRICS      | SEMI       | WAVG      |
-| CONFIGS    | GRANTS      | MIN          | SET        | WHERE     |
-| CONFLICT   | GROUP       |              |            |           |
+| ABLOCKS    | CONNECTION  | GROUP        | MINUS      | SLASH     |
+| ABORT      | CONNECTIONS | GT           | MNODES     | SLIDING   |
+| ACCOUNT    | COPY        | ID           | MODULES    | SMALLINT  |
+| ACCOUNTS   | COUNT       | IF           | NCHAR      | SPREAD    |
+| ADD        | CREATE      | IGNORE       | NE         | STABLE    |
+| AFTER      | CTIME       | IMMEDIATE    | NONE       | STABLES   |
+| ALL        | DATABASE    | IMPORT       | NOT        | STAR      |
+| ALTER      | DATABASES   | IN           | NOTNULL    | STATEMENT |
+| AND        | DAYS        | INITIALLY    | NOW        | STDDEV    |
+| AS         | DEFERRED    | INSERT       | OF         | STREAM    |
+| ASC        | DELIMITERS  | INSTEAD      | OFFSET     | STREAMS   |
+| ATTACH     | DESC        | INTEGER      | OR         | STRING    |
+| AVG        | DESCRIBE    | INTERVAL     | ORDER      | SUM       |
+| BEFORE     | DETACH      | INTO         | PASS       | TABLE     |
+| BEGIN      | DIFF        | IP           | PERCENTILE | TABLES    |
+| BETWEEN    | DISTINCT    | IS           | PLUS       | TAG       |
+| BIGINT     | DIVIDE      | ISNULL       | PRAGMA     | TAGS      |
+| BINARY     | DNODE       | JOIN         | PREV       | TBLOCKS   |
+| BITAND     | DNODES      | KEEP         | PRIVILEGE  | TBNAME    |
+| BITNOT     | DOT         | KEY          | QUERIES    | TIMES     |
+| BITOR      | DOUBLE      | KILL         | QUERY      | TIMESTAMP |
+| BOOL       | DROP        | LAST         | RAISE      | TINYINT   |
+| BOTTOM     | EACH        | LE           | REM        | TOP       |
+| BY         | END         | LEASTSQUARES | REPLACE    | TRIGGER   |
+| CACHE      | EQ          | LIKE         | REPLICA    | UMINUS    |
+| CASCADE    | EXISTS      | LIMIT        | RESET      | UPLUS     |
+| CHANGE     | EXPLAIN     | LINEAR       | RESTRICT   | USE       |
+| CLOG       | FAIL        | LOCAL        | ROW        | USER      |
+| CLUSTER    | FILL        | LP           | ROWS       | USERS     |
+| COLON      | FIRST       | LSHIFT       | RP         | USING     |
+| COLUMN     | FLOAT       | LT           | RSHIFT     | VALUES    |
+| COMMA      | FOR         | MATCH        | SCORES     | VARIABLE  |
+| COMP       | FROM        | MAX          | SELECT     | VGROUPS   |
+| CONCAT     | GE          | METRIC       | SEMI       | VIEW      |
+| CONFIGS    | GLOB        | METRICS      | SET        | WAVG      |
+| CONFLICT   | GRANTS      | MIN          | SHOW       | WHERE     |
--- a/documentation20/webdocs/markdowndocs/architecture-ch.md
+++ b/documentation20/webdocs/markdowndocs/architecture-ch.md
@ -344,7 +344,6 @@ dataDir /mnt/disk6/taos 2
 挂载的盘也可以是非本地的网络盘，只要系统能访问即可。

 注：多级存储功能仅企业版支持
-**提示：该功能暂未提供**

 ## 数据查询
 TDengine提供了多种多样针对表和超级表的查询处理功能，除了常规的聚合查询之外，还提供针对时序数据的窗口查询、统计聚合等功能。TDengine的查询处理需要客户端、vnode, mnode节点协同完成。
--- a/packaging/cfg/taos.cfg
+++ b/packaging/cfg/taos.cfg
@ -270,3 +270,9 @@

 # in retrieve blocking model, only in 50% query threads will be used in query processing in dnode
 # retrieveBlockingModel    0
+
+# the maximum allowed query buffer size in MB during query processing for each data node
+# -1 no limit (default)
+# 0  no query allowed, queries are disabled
+# queryBufferSize         -1
+
--- a/packaging/deb/makedeb.sh
+++ b/packaging/deb/makedeb.sh
@ -43,11 +43,13 @@ mkdir -p ${pkg_dir}${install_home_path}/include
 mkdir -p ${pkg_dir}${install_home_path}/init.d
 mkdir -p ${pkg_dir}${install_home_path}/script
 
-echo "" >                                           ${pkg_dir}${install_home_path}/email
 cp ${compile_dir}/../packaging/cfg/taos.cfg         ${pkg_dir}${install_home_path}/cfg
 cp ${compile_dir}/../packaging/deb/taosd            ${pkg_dir}${install_home_path}/init.d
 cp ${compile_dir}/../packaging/tools/post.sh        ${pkg_dir}${install_home_path}/script
 cp ${compile_dir}/../packaging/tools/preun.sh       ${pkg_dir}${install_home_path}/script
+cp ${compile_dir}/../packaging/tools/startPre.sh    ${pkg_dir}${install_home_path}/bin
+cp ${compile_dir}/../packaging/tools/set_core.sh    ${pkg_dir}${install_home_path}/bin
+cp ${compile_dir}/../packaging/tools/taosd-dump-cfg.gdb    ${pkg_dir}${install_home_path}/bin
 cp ${compile_dir}/build/bin/taosdemo                ${pkg_dir}${install_home_path}/bin
 cp ${compile_dir}/build/bin/taosdemox               ${pkg_dir}${install_home_path}/bin
 cp ${compile_dir}/build/bin/taosdump                ${pkg_dir}${install_home_path}/bin
--- a/packaging/rpm/tdengine.spec
+++ b/packaging/rpm/tdengine.spec
@ -51,11 +51,13 @@ mkdir -p %{buildroot}%{homepath}/include
 mkdir -p %{buildroot}%{homepath}/init.d
 mkdir -p %{buildroot}%{homepath}/script

-echo "" > %{buildroot}%{homepath}/email
 cp %{_compiledir}/../packaging/cfg/taos.cfg         %{buildroot}%{homepath}/cfg
 cp %{_compiledir}/../packaging/rpm/taosd            %{buildroot}%{homepath}/init.d
 cp %{_compiledir}/../packaging/tools/post.sh        %{buildroot}%{homepath}/script
 cp %{_compiledir}/../packaging/tools/preun.sh       %{buildroot}%{homepath}/script
+cp %{_compiledir}/../packaging/tools/startPre.sh    %{buildroot}%{homepath}/bin
+cp %{_compiledir}/../packaging/tools/set_core.sh    %{buildroot}%{homepath}/bin
+cp %{_compiledir}/../packaging/tools/taosd-dump-cfg.gdb    %{buildroot}%{homepath}/bin
 cp %{_compiledir}/build/bin/taos                    %{buildroot}%{homepath}/bin
 cp %{_compiledir}/build/bin/taosd                   %{buildroot}%{homepath}/bin
 cp %{_compiledir}/build/bin/taosdemo                %{buildroot}%{homepath}/bin
--- a/packaging/tools/install.sh
+++ b/packaging/tools/install.sh
@ -604,9 +604,7 @@ function install_service_on_systemd() {
    ${csudo} bash -c "echo '[Service]'                          >> ${taosd_service_config}"
    ${csudo} bash -c "echo 'Type=simple'                        >> ${taosd_service_config}"
    ${csudo} bash -c "echo 'ExecStart=/usr/bin/taosd'           >> ${taosd_service_config}"
-    #${csudo} bash -c "echo 'ExecStartPre=/usr/local/taos/bin/setDelay.sh'     >> ${taosd_service_config}"
-    #${csudo} bash -c "echo 'ExecStartPost=/usr/local/taos/bin/resetDelay.sh'  >> ${taosd_service_config}"
-    #${csudo} bash -c "echo 'ExecStopPost=/usr/local/taos/bin/resetDelay.sh'   >> ${taosd_service_config}"
+    ${csudo} bash -c "echo 'ExecStartPre=/usr/local/taos/bin/startPre.sh'         >> ${taosd_service_config}"
    ${csudo} bash -c "echo 'LimitNOFILE=infinity'               >> ${taosd_service_config}"
    ${csudo} bash -c "echo 'LimitNPROC=infinity'                >> ${taosd_service_config}"
    ${csudo} bash -c "echo 'LimitCORE=infinity'                 >> ${taosd_service_config}"
--- a/packaging/tools/install_power.sh
+++ b/packaging/tools/install_power.sh
@ -578,6 +578,7 @@ function install_service_on_systemd() {
    ${csudo} bash -c "echo '[Service]'                           >> ${powerd_service_config}"
    ${csudo} bash -c "echo 'Type=simple'                         >> ${powerd_service_config}"
    ${csudo} bash -c "echo 'ExecStart=/usr/bin/powerd'           >> ${powerd_service_config}"
+    ${csudo} bash -c "echo 'ExecStartPre=/usr/local/power/bin/startPre.sh'           >> ${powerd_service_config}"
    ${csudo} bash -c "echo 'LimitNOFILE=infinity'                >> ${powerd_service_config}"
    ${csudo} bash -c "echo 'LimitNPROC=infinity'                 >> ${powerd_service_config}"
    ${csudo} bash -c "echo 'LimitCORE=infinity'                  >> ${powerd_service_config}"
--- a/packaging/tools/make_install.sh
+++ b/packaging/tools/make_install.sh
@ -149,10 +149,12 @@ function install_bin() {
    ${csudo} rm -f ${bin_link_dir}/rmtaos       || :

    ${csudo} cp -r ${binary_dir}/build/bin/* ${install_main_dir}/bin
+    ${csudo} cp -r ${script_dir}/taosd-dump-cfg.gdb   ${install_main_dir}/bin

    if [ "$osType" != "Darwin" ]; then
-        ${csudo} cp -r ${script_dir}/remove.sh   ${install_main_dir}/bin
+        ${csudo} cp -r ${script_dir}/remove.sh     ${install_main_dir}/bin
        ${csudo} cp -r ${script_dir}/set_core.sh   ${install_main_dir}/bin
+        ${csudo} cp -r ${script_dir}/startPre.sh   ${install_main_dir}/bin
    else
        ${csudo} cp -r ${script_dir}/remove_client.sh   ${install_main_dir}/bin
    fi
@ -330,6 +332,7 @@ function install_service_on_systemd() {
    ${csudo} bash -c "echo '[Service]'                          >> ${taosd_service_config}"
    ${csudo} bash -c "echo 'Type=simple'                        >> ${taosd_service_config}"
    ${csudo} bash -c "echo 'ExecStart=/usr/bin/taosd'           >> ${taosd_service_config}"
+    ${csudo} bash -c "echo 'ExecStartPre=/usr/local/taos/bin/startPre.sh'           >> ${taosd_service_config}"
    ${csudo} bash -c "echo 'LimitNOFILE=infinity'               >> ${taosd_service_config}"
    ${csudo} bash -c "echo 'LimitNPROC=infinity'                >> ${taosd_service_config}"
    ${csudo} bash -c "echo 'LimitCORE=infinity'                 >> ${taosd_service_config}"
--- a/packaging/tools/makeclient.sh
+++ b/packaging/tools/makeclient.sh
@ -45,7 +45,8 @@ if [ "$osType" != "Darwin" ]; then
    strip ${build_dir}/bin/taos
    bin_files="${build_dir}/bin/taos ${script_dir}/remove_client.sh"
  else  
-    bin_files="${build_dir}/bin/taos ${build_dir}/bin/taosdump ${build_dir}/bin/taosdemo ${build_dir}/bin/taosdemox ${script_dir}/remove_client.sh ${script_dir}/set_core.sh ${script_dir}/get_client.sh"
+    bin_files="${build_dir}/bin/taos ${build_dir}/bin/taosdump ${build_dir}/bin/taosdemo ${build_dir}/bin/taosdemox\
+               ${script_dir}/remove_client.sh ${script_dir}/set_core.sh ${script_dir}/get_client.sh ${script_dir}/taosd-dump-cfg.gdb"
  fi
  lib_files="${build_dir}/lib/libtaos.so.${version}"
 else
--- a/packaging/tools/makeclient_power.sh
+++ b/packaging/tools/makeclient_power.sh
@ -81,6 +81,7 @@ if [ "$osType" != "Darwin" ]; then
    cp ${build_dir}/bin/taosdump      ${install_dir}/bin/powerdump  
    cp ${script_dir}/set_core.sh      ${install_dir}/bin
    cp ${script_dir}/get_client.sh    ${install_dir}/bin
+    cp ${script_dir}/taosd-dump-cfg.gdb    ${install_dir}/bin
  fi
 else
  cp ${bin_files} ${install_dir}/bin
--- a/packaging/tools/makepkg.sh
+++ b/packaging/tools/makepkg.sh
@ -36,7 +36,8 @@ if [ "$pagMode" == "lite" ]; then
  strip ${build_dir}/bin/taos
  bin_files="${build_dir}/bin/taosd ${build_dir}/bin/taos ${script_dir}/remove.sh"
 else 
-  bin_files="${build_dir}/bin/taosd ${build_dir}/bin/taos ${build_dir}/bin/taosdump ${build_dir}/bin/taosdemo ${build_dir}/bin/taosdemox ${build_dir}/bin/tarbitrator ${script_dir}/remove.sh ${script_dir}/set_core.sh ${script_dir}/get_client.sh"
+  bin_files="${build_dir}/bin/taosd ${build_dir}/bin/taos ${build_dir}/bin/taosdump ${build_dir}/bin/taosdemo ${build_dir}/bin/taosdemox ${build_dir}/bin/tarbitrator\
+             ${script_dir}/remove.sh ${script_dir}/set_core.sh ${script_dir}/startPre.sh  ${script_dir}/taosd-dump-cfg.gdb"
 fi

 lib_files="${build_dir}/lib/libtaos.so.${version}"
--- a/packaging/tools/makepkg_power.sh
+++ b/packaging/tools/makepkg_power.sh
@ -36,7 +36,8 @@ fi
 #  strip ${build_dir}/bin/taos
 #  bin_files="${build_dir}/bin/powerd ${build_dir}/bin/power ${script_dir}/remove_power.sh"
 #else 
-#  bin_files="${build_dir}/bin/powerd ${build_dir}/bin/power ${build_dir}/bin/powerdemo ${build_dir}/bin/tarbitrator ${script_dir}/remove_power.sh ${script_dir}/set_core.sh"
+#  bin_files="${build_dir}/bin/powerd ${build_dir}/bin/power ${build_dir}/bin/powerdemo ${build_dir}/bin/tarbitrator ${script_dir}/remove_power.sh\
+#              ${script_dir}/set_core.sh ${script_dir}/startPre.sh  ${script_dir}/taosd-dump-cfg.gdb"
 #fi

 lib_files="${build_dir}/lib/libtaos.so.${version}"
@ -82,6 +83,8 @@ else
  cp ${build_dir}/bin/tarbitrator   ${install_dir}/bin
  cp ${script_dir}/set_core.sh      ${install_dir}/bin
  cp ${script_dir}/get_client.sh    ${install_dir}/bin
+  cp ${script_dir}/startPre.sh      ${install_dir}/bin
+  cp ${script_dir}/taosd-dump-cfg.gdb  ${install_dir}/bin
 fi
 chmod a+x ${install_dir}/bin/* || :

--- a/packaging/tools/post.sh
+++ b/packaging/tools/post.sh
@ -406,6 +406,7 @@ function install_service_on_systemd() {
    ${csudo} bash -c "echo '[Service]'                          >> ${taosd_service_config}"
    ${csudo} bash -c "echo 'Type=simple'                        >> ${taosd_service_config}"
    ${csudo} bash -c "echo 'ExecStart=/usr/bin/taosd'           >> ${taosd_service_config}"
+    ${csudo} bash -c "echo 'ExecStartPre=/usr/local/taos/bin/startPre.sh'           >> ${taosd_service_config}"
    ${csudo} bash -c "echo 'LimitNOFILE=infinity'               >> ${taosd_service_config}"
    ${csudo} bash -c "echo 'LimitNPROC=infinity'                >> ${taosd_service_config}"
    ${csudo} bash -c "echo 'LimitCORE=infinity'                 >> ${taosd_service_config}"
--- a/packaging/tools/startPre.sh
+++ b/packaging/tools/startPre.sh
@ -0,0 +1,50 @@
+#!/bin/bash
+#
+# if enable core dump, set start count to 3, disable core dump, set start count to 20.
+# set -e
+# set -x
+
+taosd=/etc/systemd/system/taosd.service
+line=`grep StartLimitBurst ${taosd}`
+num=${line##*=}
+#echo "burst num: ${num}"
+
+startSeqFile=/usr/local/taos/.startSeq
+recordFile=/usr/local/taos/.startRecord
+
+startSeq=0
+
+if [[ ! -e ${startSeqFile} ]]; then
+  startSeq=0
+else
+  startSeq=$(cat ${startSeqFile})
+fi
+   
+nextSeq=`expr $startSeq + 1`
+echo "${nextSeq}" > ${startSeqFile}
+
+curTime=$(date "+%Y-%m-%d %H:%M:%S")
+echo "startSeq:${startSeq} startPre.sh exec ${curTime}, burstCnt:${num}" >> ${recordFile}
+
+
+coreFlag=`ulimit -c`
+echo "coreFlag: ${coreFlag}" >> ${recordFile}
+
+if [ ${coreFlag} = "0" ];then
+  #echo "core is 0"
+  if [ ${num} != "20" ];then
+    sed -i "s/^.*StartLimitBurst.*$/StartLimitBurst=20/" ${taosd}
+    systemctl daemon-reload
+    echo "modify burst count from ${num} to 20" >> ${recordFile}
+  fi
+fi
+
+if [ ${coreFlag} = "unlimited" ];then
+  #echo "core is unlimited"
+  if [ ${num} != "3" ];then
+    sed -i "s/^.*StartLimitBurst.*$/StartLimitBurst=3/" ${taosd}
+    systemctl daemon-reload
+    echo "modify burst count from ${num} to 3" >> ${recordFile}
+  fi
+fi
+
--- a/src/client/inc/tsclient.h
+++ b/src/client/inc/tsclient.h
@ -297,6 +297,11 @@ typedef struct {
  struct SLocalMerger  *pLocalMerger;
 } SSqlRes;

+typedef struct {
+  char         key[512]; 
+  void         *pDnodeConn; 
+} SRpcObj;
+
 typedef struct STscObj {
  void *             signature;
  void *             pTimer;
@ -312,8 +317,8 @@ typedef struct STscObj {
  int64_t            hbrid;
  struct SSqlObj *   sqlList;
  struct SSqlStream *streamList;
-  SRpcCorEpSet       *tscCorMgmtEpSet;
-  void*              pDnodeConn;
+  SRpcObj           *pRpcObj;
+  SRpcCorEpSet      *tscCorMgmtEpSet;
  pthread_mutex_t    mutex;
  int32_t            numOfObj; // number of sqlObj from this tscObj
 } STscObj;
@ -390,8 +395,10 @@ typedef struct SSqlStream {

 void tscSetStreamDestTable(SSqlStream* pStream, const char* dstTable);

-int32_t tscInitRpc(const char *user, const char *secret, void** pDnodeConn);
-void    tscInitMsgsFp();
+
+int  tscAcquireRpc(const char *key, const char *user, const char *secret,void **pRpcObj);
+void tscReleaseRpc(void *param);
+void tscInitMsgsFp();

 int tsParseSql(SSqlObj *pSql, bool initial);

--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@ -5427,6 +5427,7 @@ int32_t validateColumnName(char* name) {

  if (token.type == TK_STRING) {
    strdequote(token.z);
+    strntolower(token.z, token.z, token.n);
    token.n = (uint32_t)strtrim(token.z);

    int32_t k = tSQLGetToken(token.z, &token.type);
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@ -157,13 +157,16 @@ void tscProcessHeartBeatRsp(void *param, TAOS_RES *tres, int code) {
    SRpcEpSet     *epSet = &pRsp->epSet;
    if (epSet->numOfEps > 0) {
      tscEpSetHtons(epSet);
-      if (!tscEpSetIsEqual(&pSql->pTscObj->tscCorMgmtEpSet->epSet, epSet)) {
-        tscTrace("%p updating epset: numOfEps: %d, inUse: %d", pSql, epSet->numOfEps, epSet->inUse);
-        for (int8_t i = 0; i < epSet->numOfEps; i++) {
-          tscTrace("endpoint %d: fqdn=%s, port=%d", i, epSet->fqdn[i], epSet->port[i]);
-        }
-        tscUpdateMgmtEpSet(pSql, epSet);
-      }
+
+      //SRpcCorEpSet *pCorEpSet = pSql->pTscObj->tscCorMgmtEpSet;
+      //if (!tscEpSetIsEqual(&pCorEpSet->epSet, epSet)) {
+      //  tscTrace("%p updating epset: numOfEps: %d, inUse: %d", pSql, epSet->numOfEps, epSet->inUse);
+      //  for (int8_t i = 0; i < epSet->numOfEps; i++) {
+      //    tscTrace("endpoint %d: fqdn=%s, port=%d", i, epSet->fqdn[i], epSet->port[i]);
+      //  }
+      //}
+      //concurrency problem, update mgmt epset anyway 
+      tscUpdateMgmtEpSet(pSql, epSet);
    }

    pSql->pTscObj->connId = htonl(pRsp->connId);
@ -270,7 +273,8 @@ int tscSendMsgToServer(SSqlObj *pSql) {
      .code    = 0
  };

-  rpcSendRequest(pObj->pDnodeConn, &pSql->epSet, &rpcMsg, &pSql->rpcRid);
+  
+  rpcSendRequest(pObj->pRpcObj->pDnodeConn, &pSql->epSet, &rpcMsg, &pSql->rpcRid);
  return TSDB_CODE_SUCCESS;
 }

@ -292,8 +296,8 @@ void tscProcessMsgFromServer(SRpcMsg *rpcMsg, SRpcEpSet *pEpSet) {
  if (pObj->signature != pObj) {
    tscDebug("%p DB connection is closed, cmd:%d pObj:%p signature:%p", pSql, pCmd->command, pObj, pObj->signature);

-    taosRemoveRef(tscObjRef, pSql->self);
-    taosReleaseRef(tscObjRef, pSql->self);
+    taosRemoveRef(tscObjRef, handle);
+    taosReleaseRef(tscObjRef, handle);
    rpcFreeCont(rpcMsg->pCont);
    return;
  }
@ -303,8 +307,8 @@ void tscProcessMsgFromServer(SRpcMsg *rpcMsg, SRpcEpSet *pEpSet) {
    tscDebug("%p sqlObj needs to be released or DB connection is closed, cmd:%d type:%d, pObj:%p signature:%p",
        pSql, pCmd->command, pQueryInfo->type, pObj, pObj->signature);

-    taosRemoveRef(tscObjRef, pSql->self);
-    taosReleaseRef(tscObjRef, pSql->self);
+    taosRemoveRef(tscObjRef, handle);
+    taosReleaseRef(tscObjRef, handle);
    rpcFreeCont(rpcMsg->pCont);
    return;
  }
@ -350,7 +354,7 @@ void tscProcessMsgFromServer(SRpcMsg *rpcMsg, SRpcEpSet *pEpSet) {

      // if there is an error occurring, proceed to the following error handling procedure.
      if (rpcMsg->code == TSDB_CODE_TSC_ACTION_IN_PROGRESS) {
-        taosReleaseRef(tscObjRef, pSql->self);
+        taosReleaseRef(tscObjRef, handle);
        rpcFreeCont(rpcMsg->pCont);
        return;
      }
@ -418,13 +422,15 @@ void tscProcessMsgFromServer(SRpcMsg *rpcMsg, SRpcEpSet *pEpSet) {
    (*pSql->fp)(pSql->param, pSql, rpcMsg->code);
  }

-  taosReleaseRef(tscObjRef, pSql->self);
+  

  if (shouldFree) { // in case of table-meta/vgrouplist query, automatically free it
-    taosRemoveRef(tscObjRef, pSql->self);
+    taosRemoveRef(tscObjRef, handle);
    tscDebug("%p sqlObj is automatically freed", pSql); 
  }

+  taosReleaseRef(tscObjRef, handle);
+
  rpcFreeCont(rpcMsg->pCont);
 }

--- a/src/client/src/tscSql.c
+++ b/src/client/src/tscSql.c
@ -90,9 +90,11 @@ static SSqlObj *taosConnectImpl(const char *ip, const char *user, const char *pa
  } else {
    if (tscSetMgmtEpSetFromCfg(tsFirst, tsSecond, &corMgmtEpSet) < 0) return NULL;
  }
+  char rpcKey[512] = {0};
+  snprintf(rpcKey, sizeof(rpcKey), "%s:%s:%s:%d", user, pass, ip, port);
 
-  void *pDnodeConn = NULL;
-  if (tscInitRpc(user, secretEncrypt, &pDnodeConn) != 0) {
+  void *pRpcObj = NULL;
+  if (tscAcquireRpc(rpcKey, user, secretEncrypt, &pRpcObj) != 0) {
    terrno = TSDB_CODE_RPC_NETWORK_UNAVAIL;
    return NULL;
  }
@ -100,23 +102,21 @@ static SSqlObj *taosConnectImpl(const char *ip, const char *user, const char *pa
  STscObj *pObj = (STscObj *)calloc(1, sizeof(STscObj));
  if (NULL == pObj) {
    terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
-    rpcClose(pDnodeConn);
+    tscReleaseRpc(pRpcObj);
    return NULL;
  }
-  // set up tscObj's mgmtEpSet
-  pObj->tscCorMgmtEpSet = (SRpcCorEpSet *)malloc(sizeof(SRpcCorEpSet));
-  if (NULL == pObj->tscCorMgmtEpSet) {
+
+  pObj->tscCorMgmtEpSet = malloc(sizeof(SRpcCorEpSet));
+  if (pObj->tscCorMgmtEpSet == NULL) {
    terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
-    rpcClose(pDnodeConn);
-    free(pObj->tscCorMgmtEpSet);
+    tscReleaseRpc(pRpcObj);
    free(pObj);
    return NULL;
  }
-  memcpy(pObj->tscCorMgmtEpSet, &corMgmtEpSet, sizeof(SRpcCorEpSet));
-
-  pObj->signature = pObj;
-  pObj->pDnodeConn = pDnodeConn;
+  memcpy(pObj->tscCorMgmtEpSet, &corMgmtEpSet, sizeof(corMgmtEpSet));
  
+  pObj->signature = pObj;
+  pObj->pRpcObj = (SRpcObj *)pRpcObj;
  tstrncpy(pObj->user, user, sizeof(pObj->user));
  secretEncryptLen = MIN(secretEncryptLen, sizeof(pObj->pass));
  memcpy(pObj->pass, secretEncrypt, secretEncryptLen);
@ -126,8 +126,7 @@ static SSqlObj *taosConnectImpl(const char *ip, const char *user, const char *pa
    /* db name is too long */
    if (len >= TSDB_DB_NAME_LEN) {
      terrno = TSDB_CODE_TSC_INVALID_DB_LENGTH;
-      rpcClose(pDnodeConn);
-      free(pObj->tscCorMgmtEpSet);
+      tscReleaseRpc(pRpcObj);
      free(pObj);
      return NULL;
    }
@ -144,8 +143,7 @@ static SSqlObj *taosConnectImpl(const char *ip, const char *user, const char *pa
  SSqlObj *pSql = (SSqlObj *)calloc(1, sizeof(SSqlObj));
  if (NULL == pSql) {
    terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
-    rpcClose(pDnodeConn);
-    free(pObj->tscCorMgmtEpSet);
+    tscReleaseRpc(pRpcObj);
    free(pObj);
    return NULL;
  }
@ -161,9 +159,8 @@ static SSqlObj *taosConnectImpl(const char *ip, const char *user, const char *pa

  if (TSDB_CODE_SUCCESS != tscAllocPayload(&pSql->cmd, TSDB_DEFAULT_PAYLOAD_SIZE)) {
    terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
-    rpcClose(pDnodeConn);
+    tscReleaseRpc(pRpcObj);
    free(pSql);
-    free(pObj->tscCorMgmtEpSet);
    free(pObj);
    return NULL;
  }
@ -202,7 +199,7 @@ TAOS *taos_connect_internal(const char *ip, const char *user, const char *pass,
      return NULL;
    }
    
-    tscDebug("%p DB connection is opening, dnodeConn:%p", pObj, pObj->pDnodeConn);
+    tscDebug("%p DB connection is opening, rpcObj: %p, dnodeConn:%p", pObj, pObj->pRpcObj, pObj->pRpcObj->pDnodeConn);
    taos_free_result(pSql);
  
    // version compare only requires the first 3 segments of the version string
@ -279,7 +276,7 @@ void taos_close(TAOS *taos) {
    return;
  }

-  tscDebug("%p try to free tscObj and close dnodeConn:%p", pObj, pObj->pDnodeConn);
+  tscDebug("%p try to free tscObj", pObj);
  if (pObj->signature != pObj) {
    tscDebug("%p already closed or invalid tscObj", pObj);
    return;
@ -303,7 +300,7 @@ void taos_close(TAOS *taos) {
    }
  }

-  tscDebug("%p all sqlObj are freed, free tscObj and close dnodeConn:%p", pObj, pObj->pDnodeConn);
+  tscDebug("%p all sqlObj are freed, free tscObj", pObj);
  taosRemoveRef(tscRefId, pObj->rid);
 }

--- a/src/client/src/tscSystem.c
+++ b/src/client/src/tscSystem.c
@ -42,41 +42,74 @@ void      *tscTmr;
 void      *tscQhandle;
 int32_t    tscRefId = -1;
 int32_t    tscNumOfObj = 0;         // number of sqlObj in current process.
-
 static void  *tscCheckDiskUsageTmr;
+void      *tscRpcCache;            // cache to keep rpc obj
+int32_t   tscNumOfThreads = 1;     // num of rpc threads  
+static    pthread_mutex_t rpcObjMutex; // mutex to protect open the rpc obj concurrently 
 static pthread_once_t tscinit = PTHREAD_ONCE_INIT;

 void tscCheckDiskUsage(void *UNUSED_PARAM(para), void *UNUSED_PARAM(param)) {
  taosGetDisk();
  taosTmrReset(tscCheckDiskUsage, 1000, NULL, tscTmr, &tscCheckDiskUsageTmr);
 }
+void tscFreeRpcObj(void *param) {
+  assert(param);
+  SRpcObj *pRpcObj = (SRpcObj *)(param);
+  tscDebug("free rpcObj:%p and free pDnodeConn: %p", pRpcObj, pRpcObj->pDnodeConn);
+  rpcClose(pRpcObj->pDnodeConn);
+}

-int32_t tscInitRpc(const char *user, const char *secretEncrypt, void **pDnodeConn) {
-  SRpcInit rpcInit;
-
-  if (*pDnodeConn == NULL) {
-    memset(&rpcInit, 0, sizeof(rpcInit));
-    rpcInit.localPort = 0;
-    rpcInit.label = "TSC";
-    rpcInit.numOfThreads = 1;  // every DB connection has only one thread
-    rpcInit.cfp = tscProcessMsgFromServer;
-    rpcInit.sessions = tsMaxConnections;
-    rpcInit.connType = TAOS_CONN_CLIENT;
-    rpcInit.user = (char *)user;
-    rpcInit.idleTime = 2000;
-    rpcInit.ckey = "key";
-    rpcInit.spi = 1;
-    rpcInit.secret = (char *)secretEncrypt;
-
-    *pDnodeConn = rpcOpen(&rpcInit);
-    if (*pDnodeConn == NULL) {
-      tscError("failed to init connection to TDengine");
-      return -1;
-    } else {
-      tscDebug("dnodeConn:%p is created, user:%s", *pDnodeConn, user);
-    }
+void tscReleaseRpc(void *param)  {
+  if (param == NULL) {
+    return;
  }
+  pthread_mutex_lock(&rpcObjMutex);
+  taosCacheRelease(tscRpcCache, (void *)&param, false); 
+  pthread_mutex_unlock(&rpcObjMutex);
+} 

+int32_t tscAcquireRpc(const char *key, const char *user, const char *secretEncrypt, void **ppRpcObj) {
+  pthread_mutex_lock(&rpcObjMutex);
+
+  SRpcObj *pRpcObj = (SRpcObj *)taosCacheAcquireByKey(tscRpcCache, key, strlen(key));
+  if (pRpcObj != NULL) {
+    *ppRpcObj = pRpcObj;   
+    pthread_mutex_unlock(&rpcObjMutex);
+    return 0;
+  } 
+
+  SRpcInit rpcInit;
+  memset(&rpcInit, 0, sizeof(rpcInit));
+  rpcInit.localPort = 0;
+  rpcInit.label = "TSC";
+  rpcInit.numOfThreads = tscNumOfThreads * 2;    
+  rpcInit.cfp = tscProcessMsgFromServer;
+  rpcInit.sessions = tsMaxConnections;
+  rpcInit.connType = TAOS_CONN_CLIENT;
+  rpcInit.user = (char *)user;
+  rpcInit.idleTime = 2000; 
+  rpcInit.ckey = "key"; 
+  rpcInit.spi = 1; 
+  rpcInit.secret = (char *)secretEncrypt;
+
+  SRpcObj rpcObj;
+  memset(&rpcObj, 0, sizeof(rpcObj));
+  strncpy(rpcObj.key, key, strlen(key));
+  rpcObj.pDnodeConn = rpcOpen(&rpcInit);
+  if (rpcObj.pDnodeConn == NULL) {
+    pthread_mutex_unlock(&rpcObjMutex);
+    tscError("failed to init connection to TDengine");
+    return -1;
+  } 
+  pRpcObj = taosCachePut(tscRpcCache, rpcObj.key, strlen(rpcObj.key), &rpcObj, sizeof(rpcObj), 1000*10);   
+  if (pRpcObj == NULL) {
+    rpcClose(rpcObj.pDnodeConn);
+    pthread_mutex_unlock(&rpcObjMutex);
+    return -1;
+  } 
+
+  *ppRpcObj  = pRpcObj;
+  pthread_mutex_unlock(&rpcObjMutex);
  return 0;
 }

@ -117,7 +150,7 @@ void taos_init_imp(void) {
  int queueSize = tsMaxConnections*2;

  double factor = (tscEmbedded == 0)? 2.0:4.0;
-  int32_t tscNumOfThreads = (int)(tsNumOfCores * tsNumOfThreadsPerCore / factor);
+  tscNumOfThreads = (int)(tsNumOfCores * tsNumOfThreadsPerCore / factor);
  if (tscNumOfThreads < 2) {
    tscNumOfThreads = 2;
  }
@ -139,6 +172,10 @@ void taos_init_imp(void) {
    tscTableMetaInfo = taosHashInit(1024, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BINARY), true, HASH_ENTRY_LOCK);
    tscDebug("TableMeta:%p", tscTableMetaInfo);
  }
+   
+  int refreshTime = 5;
+  tscRpcCache = taosCacheInit(TSDB_DATA_TYPE_BINARY, refreshTime, true, tscFreeRpcObj, "rpcObj");
+  pthread_mutex_init(&rpcObjMutex, NULL);

  tscRefId = taosOpenRef(200, tscCloseTscObj);

@ -180,10 +217,16 @@ void taos_cleanup(void) {
  taosCleanupKeywordsTable();
  taosCloseLog();

-  if (tscEmbedded == 0) {
-    rpcCleanup();
+  p = tscRpcCache; 
+  tscRpcCache = NULL;
+  
+  if (p != NULL) {
+    taosCacheCleanup(p); 
+    pthread_mutex_destroy(&rpcObjMutex);
  }

+  if (tscEmbedded == 0) rpcCleanup();
+
  p = tscTmr;
  tscTmr = NULL;
  taosTmrCleanUp(p);
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@ -32,6 +32,14 @@
 static void freeQueryInfoImpl(SQueryInfo* pQueryInfo);
 static void clearAllTableMetaInfo(SQueryInfo* pQueryInfo);

+static void tscStrToLower(char *str, int32_t n) {
+  if (str == NULL || n <= 0) { return;}
+  for (int32_t i = 0; i < n; i++) {
+    if (str[i] >= 'A' && str[i] <= 'Z') {
+        str[i] -= ('A' - 'a');
+    }
+  }
+}
 SCond* tsGetSTableQueryCond(STagCond* pTagCond, uint64_t uid) {
  if (pTagCond->pCond == NULL) {
    return NULL;
@ -447,7 +455,6 @@ void tscFreeRegisteredSqlObj(void *pSql) {

  SSqlObj* p = *(SSqlObj**)pSql;
  STscObj* pTscObj = p->pTscObj;
-
  assert(RID_VALID(p->self));

  int32_t num   = atomic_sub_fetch_32(&pTscObj->numOfObj, 1);
@ -898,16 +905,10 @@ void tscCloseTscObj(void *param) {
  pObj->signature = NULL;
  taosTmrStopA(&(pObj->pTimer));

-  void* p = pObj->pDnodeConn;
-  if (pObj->pDnodeConn != NULL) {
-    rpcClose(pObj->pDnodeConn);
-    pObj->pDnodeConn = NULL;
-  }
-
  tfree(pObj->tscCorMgmtEpSet);
+  tscReleaseRpc(pObj->pRpcObj);
  pthread_mutex_destroy(&pObj->mutex);

-  tscDebug("%p DB connection is closed, dnodeConn:%p", pObj, p);
  tfree(pObj);
 }

@ -1420,9 +1421,11 @@ int32_t tscValidateName(SStrToken* pToken) {
  char* sep = strnchr(pToken->z, TS_PATH_DELIMITER[0], pToken->n, true);
  if (sep == NULL) {  // single part
    if (pToken->type == TK_STRING) {
+       
      strdequote(pToken->z);
+      tscStrToLower(pToken->z, pToken->n);
      pToken->n = (uint32_t)strtrim(pToken->z);
-
+       
      int len = tSQLGetToken(pToken->z, &pToken->type);

      // single token, validate it
@ -1474,7 +1477,7 @@ int32_t tscValidateName(SStrToken* pToken) {
    if (pToken->type == TK_STRING && validateQuoteToken(pToken) != TSDB_CODE_SUCCESS) {
      return TSDB_CODE_TSC_INVALID_SQL;
    }
-
+    
    // re-build the whole name string
    if (pStr[firstPartLen] == TS_PATH_DELIMITER[0]) {
      // first part do not have quote do nothing
@ -1486,6 +1489,8 @@ int32_t tscValidateName(SStrToken* pToken) {
    }
    pToken->n += (firstPartLen + sizeof(TS_PATH_DELIMITER[0]));
    pToken->z = pStr;
+
+    tscStrToLower(pToken->z,pToken->n);
  }

  return TSDB_CODE_SUCCESS;
--- a/src/common/inc/tglobal.h
+++ b/src/common/inc/tglobal.h
@ -59,7 +59,8 @@ extern int32_t  tsCompressMsgSize;
 extern char     tsTempDir[];

 //query buffer management
-extern int32_t  tsQueryBufferSize;      // maximum allowed usage buffer for each data node during query processing
+extern int32_t  tsQueryBufferSize;      // maximum allowed usage buffer size in MB for each data node during query processing
+extern int64_t  tsQueryBufferSizeBytes; // maximum allowed usage buffer size in byte for each data node during query processing
 extern int32_t  tsRetrieveBlockingModel;// retrieve threads will be blocked

 extern int8_t   tsKeepOriginalColumnName;
--- a/src/common/src/tglobal.c
+++ b/src/common/src/tglobal.c
@ -105,6 +105,7 @@ int64_t tsMaxRetentWindow = 24 * 3600L;  // maximum time window tolerance
 // 0  no query allowed, queries are disabled
 // positive value (in MB)
 int32_t tsQueryBufferSize = -1;
+int64_t tsQueryBufferSizeBytes = -1;

 // in retrieve blocking model, the retrieve threads will wait for the completion of the query processing.
 int32_t tsRetrieveBlockingModel = 0;
@ -291,7 +292,7 @@ bool taosCfgDynamicOptions(char *msg) {
    int32_t cfgLen = (int32_t)strlen(cfg->option);
    if (cfgLen != olen) continue;
    if (strncasecmp(option, cfg->option, olen) != 0) continue;
-    if (cfg->valType != TAOS_CFG_VTYPE_INT32) {
+    if (cfg->valType == TAOS_CFG_VTYPE_INT32) {
      *((int32_t *)cfg->ptr) = vint;
    } else {
      *((int8_t *)cfg->ptr) = (int8_t)vint;
@ -1530,6 +1531,10 @@ int32_t taosCheckGlobalCfg() {
  tsSyncPort = tsServerPort + TSDB_PORT_SYNC;
  tsHttpPort = tsServerPort + TSDB_PORT_HTTP;

+  if (tsQueryBufferSize >= 0) {
+    tsQueryBufferSizeBytes = tsQueryBufferSize * 1048576UL;
+  }
+
  taosPrintGlobalCfg();

  return 0;
--- a/src/common/src/ttypes.c
+++ b/src/common/src/ttypes.c
@ -632,7 +632,7 @@ int32_t tStrToInteger(const char* z, int16_t type, int32_t n, int64_t* value, bo
  }

  // the string may be overflow according to errno
-  *value = issigned? strtoll(z, &endPtr, radix):strtoul(z, &endPtr, radix);
+  *value = issigned? strtoll(z, &endPtr, radix):strtoull(z, &endPtr, radix);

  // not a valid integer number, return error
  if (endPtr - z != n || errno == ERANGE) {
--- a/src/cq/src/cqMain.c
+++ b/src/cq/src/cqMain.c
@ -50,10 +50,13 @@ typedef struct {
  void    *dbConn;
  void    *tmrCtrl;
  pthread_mutex_t mutex;
+  int32_t delete;
+  int32_t cqObjNum;
 } SCqContext;

 typedef struct SCqObj {
  tmr_h          tmrId;
+  int64_t        rid;
  uint64_t       uid;
  int32_t        tid;      // table ID
  int32_t        rowSize;  // bytes of a row
@ -69,6 +72,84 @@ typedef struct SCqObj {
 static void cqProcessStreamRes(void *param, TAOS_RES *tres, TAOS_ROW row); 
 static void cqCreateStream(SCqContext *pContext, SCqObj *pObj);

+int32_t    cqObjRef = -1;
+
+void cqRmFromList(SCqObj *pObj) {
+  //LOCK in caller
+
+  SCqContext *pContext = pObj->pContext;
+
+  if (pObj->prev) {
+    pObj->prev->next = pObj->next;
+  } else {
+    pContext->pHead = pObj->next;
+  }
+
+  if (pObj->next) {
+    pObj->next->prev = pObj->prev;
+  }
+
+}
+
+void cqFree(void *handle) {
+  if (tsEnableStream == 0) {
+    return;
+  }
+  SCqObj *pObj = handle;
+  SCqContext *pContext = pObj->pContext;
+  int32_t delete = 0;
+
+  pthread_mutex_lock(&pContext->mutex);
+  
+  // free the resources associated
+  if (pObj->pStream) {
+    taos_close_stream(pObj->pStream);
+    pObj->pStream = NULL;
+  } else {
+    taosTmrStop(pObj->tmrId);
+    pObj->tmrId = 0;
+  }
+
+  cInfo("vgId:%d, id:%d CQ:%s is dropped", pContext->vgId, pObj->tid, pObj->sqlStr); 
+  tdFreeSchema(pObj->pSchema);
+  free(pObj->dstTable);
+  free(pObj->sqlStr);
+  free(pObj);
+
+  pContext->cqObjNum--;
+
+  if (pContext->cqObjNum <= 0 && pContext->delete) {
+    delete = 1;
+  }
+
+  pthread_mutex_unlock(&pContext->mutex);
+
+  if (delete) {
+    pthread_mutex_unlock(&pContext->mutex);
+    
+    pthread_mutex_destroy(&pContext->mutex);
+    
+    taosTmrCleanUp(pContext->tmrCtrl);
+    pContext->tmrCtrl = NULL;
+    
+    cDebug("vgId:%d, CQ is closed", pContext->vgId);
+    free(pContext);
+  }
+}
+
+
+void cqCreateRef() {
+  int32_t ref = atomic_load_32(&cqObjRef);
+  if (ref == -1) {
+    ref = taosOpenRef(4096, cqFree);
+
+    if (atomic_val_compare_exchange_32(&cqObjRef, -1, ref) != -1) {
+      taosCloseRef(ref);
+    }  
+  }
+}
+
+
 void *cqOpen(void *ahandle, const SCqCfg *pCfg) {
  if (tsEnableStream == 0) {
    return NULL;
@ -79,6 +160,8 @@ void *cqOpen(void *ahandle, const SCqCfg *pCfg) {
    return NULL;
  }

+  cqCreateRef();
+
  pContext->tmrCtrl = taosTmrInit(0, 0, 0, "CQ");

  tstrncpy(pContext->user, pCfg->user, sizeof(pContext->user));
@ -97,6 +180,7 @@ void *cqOpen(void *ahandle, const SCqCfg *pCfg) {

  pthread_mutex_init(&pContext->mutex, NULL);

+
  cDebug("vgId:%d, CQ is opened", pContext->vgId);

  return pContext;
@ -109,30 +193,30 @@ void cqClose(void *handle) {
  SCqContext *pContext = handle;
  if (handle == NULL) return;

+  pContext->delete = 1;
+  
  // stop all CQs
  cqStop(pContext);

-  // free all resources
-  pthread_mutex_lock(&pContext->mutex);
+  int64_t rid = 0;

-  SCqObj *pObj = pContext->pHead;
-  while (pObj) {
-    SCqObj *pTemp = pObj;
-    pObj = pObj->next;
-    tdFreeSchema(pTemp->pSchema);
-    tfree(pTemp->sqlStr);
-    free(pTemp);
-  } 
-  
-  pthread_mutex_unlock(&pContext->mutex);
+  while (1) {
+    pthread_mutex_lock(&pContext->mutex);

-  pthread_mutex_destroy(&pContext->mutex);
+    SCqObj *pObj = pContext->pHead;
+    if (pObj) {
+      cqRmFromList(pObj);

-  taosTmrCleanUp(pContext->tmrCtrl);
-  pContext->tmrCtrl = NULL;
-
-  cDebug("vgId:%d, CQ is closed", pContext->vgId);
-  free(pContext);
+      rid = pObj->rid;
+    } else {      
+      pthread_mutex_unlock(&pContext->mutex);
+      break;
+    }
+    
+    pthread_mutex_unlock(&pContext->mutex);
+    
+    taosRemoveRef(cqObjRef, rid);
+  }
 }

 void cqStart(void *handle) {
@ -191,7 +275,8 @@ void *cqCreate(void *handle, uint64_t uid, int32_t sid, const char* dstTable, ch
    return NULL;
  }
  SCqContext *pContext = handle;
-
+  int64_t rid = 0;
+  
  SCqObj *pObj = calloc(sizeof(SCqObj), 1);
  if (pObj == NULL) return NULL;

@ -213,32 +298,36 @@ void *cqCreate(void *handle, uint64_t uid, int32_t sid, const char* dstTable, ch
  if (pContext->pHead) pContext->pHead->prev = pObj;
  pContext->pHead = pObj;

+  pContext->cqObjNum++;
+
+  pObj->rid = taosAddRef(cqObjRef, pObj);
+
  cqCreateStream(pContext, pObj);

+  rid = pObj->rid;
+
  pthread_mutex_unlock(&pContext->mutex);

-  return pObj;
+
+  return (void *)rid;
 }

 void cqDrop(void *handle) {
  if (tsEnableStream == 0) {
    return;
  }
-  SCqObj *pObj = handle;
-  SCqContext *pContext = pObj->pContext;

+  SCqObj* pObj = (SCqObj*)taosAcquireRef(cqObjRef, (int64_t)handle);
+  if (pObj == NULL) {
+    return;
+  }
+  
+  SCqContext *pContext = pObj->pContext;
+  
  pthread_mutex_lock(&pContext->mutex);

-  if (pObj->prev) {
-    pObj->prev->next = pObj->next;
-  } else {
-    pContext->pHead = pObj->next;
-  }
-
-  if (pObj->next) {
-    pObj->next->prev = pObj->prev;
-  }
-
+  cqRmFromList(pObj);
+  
  // free the resources associated
  if (pObj->pStream) {
    taos_close_stream(pObj->pStream);
@ -248,17 +337,18 @@ void cqDrop(void *handle) {
    pObj->tmrId = 0;
  }

-  cInfo("vgId:%d, id:%d CQ:%s is dropped", pContext->vgId, pObj->tid, pObj->sqlStr); 
-  tdFreeSchema(pObj->pSchema);
-  free(pObj->dstTable);
-  free(pObj->sqlStr);
-  free(pObj);
-
  pthread_mutex_unlock(&pContext->mutex);
+
+  taosRemoveRef(cqObjRef, (int64_t)handle);
+  taosReleaseRef(cqObjRef, (int64_t)handle);
 }

 static void doCreateStream(void *param, TAOS_RES *result, int32_t code) {
-  SCqObj* pObj = (SCqObj*)param;
+  SCqObj* pObj = (SCqObj*)taosAcquireRef(cqObjRef, (int64_t)param);
+  if (pObj == NULL) {
+    return;
+  }
+  
  SCqContext* pContext = pObj->pContext;
  SSqlObj* pSql = (SSqlObj*)result;
  if (atomic_val_compare_exchange_ptr(&(pContext->dbConn), NULL, pSql->pTscObj) != NULL) {
@ -267,10 +357,16 @@ static void doCreateStream(void *param, TAOS_RES *result, int32_t code) {
  pthread_mutex_lock(&pContext->mutex);
  cqCreateStream(pContext, pObj);
  pthread_mutex_unlock(&pContext->mutex);
+
+  taosReleaseRef(cqObjRef, (int64_t)param);
 }

 static void cqProcessCreateTimer(void *param, void *tmrId) {
-  SCqObj* pObj = (SCqObj*)param;
+  SCqObj* pObj = (SCqObj*)taosAcquireRef(cqObjRef, (int64_t)param);
+  if (pObj == NULL) {
+    return;
+  }
+  
  SCqContext* pContext = pObj->pContext;

  if (pContext->dbConn == NULL) {
@ -281,6 +377,8 @@ static void cqProcessCreateTimer(void *param, void *tmrId) {
    cqCreateStream(pContext, pObj);
    pthread_mutex_unlock(&pContext->mutex);
  }
+
+  taosReleaseRef(cqObjRef, (int64_t)param);
 }

 static void cqCreateStream(SCqContext *pContext, SCqObj *pObj) {
@ -288,13 +386,13 @@ static void cqCreateStream(SCqContext *pContext, SCqObj *pObj) {

  if (pContext->dbConn == NULL) {
    cDebug("vgId:%d, create dbConn after 1000 ms", pContext->vgId);
-    pObj->tmrId = taosTmrStart(cqProcessCreateTimer, 1000, pObj, pContext->tmrCtrl);
+    pObj->tmrId = taosTmrStart(cqProcessCreateTimer, 1000, (void *)pObj->rid, pContext->tmrCtrl);
    return;
  }
  pObj->tmrId = 0;

  if (pObj->pStream == NULL) {
-    pObj->pStream = taos_open_stream(pContext->dbConn, pObj->sqlStr, cqProcessStreamRes, 0, pObj, NULL);
+    pObj->pStream = taos_open_stream(pContext->dbConn, pObj->sqlStr, cqProcessStreamRes, 0, (void *)pObj->rid, NULL);

    // TODO the pObj->pStream may be released if error happens
    if (pObj->pStream) {
@ -308,18 +406,28 @@ static void cqCreateStream(SCqContext *pContext, SCqObj *pObj) {
 }

 static void cqProcessStreamRes(void *param, TAOS_RES *tres, TAOS_ROW row) {
-  SCqObj *pObj = (SCqObj *)param;
+  SCqObj* pObj = (SCqObj*)taosAcquireRef(cqObjRef, (int64_t)param);
+  if (pObj == NULL) {
+    return;
+  }
+  
  if (tres == NULL && row == NULL) {
    taos_close_stream(pObj->pStream);

    pObj->pStream = NULL;
+
+    taosReleaseRef(cqObjRef, (int64_t)param);
+
    return;
  }

  SCqContext *pContext = pObj->pContext;
  STSchema   *pSchema = pObj->pSchema;
-  if (pObj->pStream == NULL) return;
-
+  if (pObj->pStream == NULL) {    
+    taosReleaseRef(cqObjRef, (int64_t)param);
+    return;
+  }
+  
  cDebug("vgId:%d, id:%d CQ:%s stream result is ready", pContext->vgId, pObj->tid, pObj->sqlStr);

  int32_t size = sizeof(SWalHead) + sizeof(SSubmitMsg) + sizeof(SSubmitBlk) + TD_DATA_ROW_HEAD_SIZE + pObj->rowSize;
@ -370,5 +478,7 @@ static void cqProcessStreamRes(void *param, TAOS_RES *tres, TAOS_ROW row) {
  // write into vnode write queue
  pContext->cqWrite(pContext->vgId, pHead, TAOS_QTYPE_CQ, NULL);
  free(buffer);
+  
+  taosReleaseRef(cqObjRef, (int64_t)param);
 }

--- a/src/dnode/src/dnodeCfg.c
+++ b/src/dnode/src/dnodeCfg.c
@ -156,7 +156,7 @@ static int32_t dnodeWriteCfg() {
  len += snprintf(content + len, maxLen - len, "}\n");

  fwrite(content, 1, len, fp);
-  fflush(fp);
+  fsync(fileno(fp));
  fclose(fp);
  free(content);
  terrno = 0;
--- a/src/dnode/src/dnodeEps.c
+++ b/src/dnode/src/dnodeEps.c
@ -277,7 +277,7 @@ static int32_t dnodeWriteEps() {
  len += snprintf(content + len, maxLen - len, "}\n");

  fwrite(content, 1, len, fp);
-  fflush(fp);
+  fsync(fileno(fp));
  fclose(fp);
  free(content);
  terrno = 0;
--- a/src/dnode/src/dnodeMInfos.c
+++ b/src/dnode/src/dnodeMInfos.c
@ -286,7 +286,7 @@ static int32_t dnodeWriteMInfos() {
  len += snprintf(content + len, maxLen - len, "}\n");

  fwrite(content, 1, len, fp);
-  fflush(fp);
+  fsync(fileno(fp));
  fclose(fp);
  free(content);
  terrno = 0;
--- a/src/mnode/src/mnodeUser.c
+++ b/src/mnode/src/mnodeUser.c
@ -123,7 +123,7 @@ static void mnodePrintUserAuth() {
    mnodeDecUserRef(pUser);
  }

-  fflush(fp);
+  fsync(fileno(fp));
  fclose(fp);
 }

--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@ -7730,15 +7730,15 @@ static int64_t getQuerySupportBufSize(size_t numOfTables) {

 int32_t checkForQueryBuf(size_t numOfTables) {
  int64_t t = getQuerySupportBufSize(numOfTables);
-  if (tsQueryBufferSize < 0) {
+  if (tsQueryBufferSizeBytes < 0) {
    return TSDB_CODE_SUCCESS;
-  } else if (tsQueryBufferSize > 0) {
+  } else if (tsQueryBufferSizeBytes > 0) {

    while(1) {
-      int64_t s = tsQueryBufferSize;
+      int64_t s = tsQueryBufferSizeBytes;
      int64_t remain = s - t;
      if (remain >= 0) {
-        if (atomic_val_compare_exchange_64(&tsQueryBufferSize, s, remain) == s) {
+        if (atomic_val_compare_exchange_64(&tsQueryBufferSizeBytes, s, remain) == s) {
          return TSDB_CODE_SUCCESS;
        }
      } else {
@ -7752,14 +7752,14 @@ int32_t checkForQueryBuf(size_t numOfTables) {
 }

 void releaseQueryBuf(size_t numOfTables) {
-  if (tsQueryBufferSize <= 0) {
+  if (tsQueryBufferSizeBytes < 0) {
    return;
  }

  int64_t t = getQuerySupportBufSize(numOfTables);

  // restore value is not enough buffer available
-  atomic_add_fetch_64(&tsQueryBufferSize, t);
+  atomic_add_fetch_64(&tsQueryBufferSizeBytes, t);
 }

 void* qGetResultRetrieveMsg(qinfo_t qinfo) {
--- a/src/rpc/src/rpcTcp.c
+++ b/src/rpc/src/rpcTcp.c
@ -48,6 +48,13 @@ typedef struct SThreadObj {
  void           *(*processData)(SRecvInfo *pPacket);
 } SThreadObj;

+typedef struct {
+  char    label[TSDB_LABEL_LEN];
+  int32_t index;
+  int numOfThreads;
+  SThreadObj **pThreadObj;
+} SClientObj;
+
 typedef struct {
  SOCKET      fd;
  uint32_t    ip;
@ -116,6 +123,7 @@ void *taosInitTcpServer(uint32_t ip, uint16_t port, char *label, int numOfThread
    pThreadObj->processData = fp;
    tstrncpy(pThreadObj->label, label, sizeof(pThreadObj->label));
    pThreadObj->shandle = shandle;
+    pThreadObj->stop = false;
  }

  // initialize mutex, thread, fd which may fail
@ -166,6 +174,7 @@ void *taosInitTcpServer(uint32_t ip, uint16_t port, char *label, int numOfThread
 }

 static void taosStopTcpThread(SThreadObj* pThreadObj) {
+  if (pThreadObj == NULL)  { return;}
  // save thread into local variable and signal thread to stop 
  pthread_t thread = pThreadObj->thread; 
  if (!taosCheckPthreadValid(thread)) {
@ -282,49 +291,76 @@ static void *taosAcceptTcpConnection(void *arg) {
  return NULL;
 }

-void *taosInitTcpClient(uint32_t ip, uint16_t port, char *label, int num, void *fp, void *shandle) {
-  SThreadObj    *pThreadObj;
+void *taosInitTcpClient(uint32_t ip, uint16_t port, char *label, int numOfThreads, void *fp, void *shandle) {
+  SClientObj *pClientObj = (SClientObj *)calloc(1, sizeof(SClientObj));
+  if (pClientObj == NULL) {
+    tError("TCP:%s no enough memory", label);
+    terrno = TAOS_SYSTEM_ERROR(errno); 
+    return NULL;
+  } 
+
+  tstrncpy(pClientObj->label, label, sizeof(pClientObj->label));
+  pClientObj->numOfThreads = numOfThreads;
+  pClientObj->pThreadObj = (SThreadObj **)calloc(numOfThreads, sizeof(SThreadObj*));  
+  if (pClientObj->pThreadObj == NULL) {
+    tError("TCP:%s no enough memory", label);
+    tfree(pClientObj);
+    terrno = TAOS_SYSTEM_ERROR(errno); 
+  }
+
+  int code = 0;
  pthread_attr_t thattr;
-
-  pThreadObj = (SThreadObj *)malloc(sizeof(SThreadObj));
-  memset(pThreadObj, 0, sizeof(SThreadObj));
-  tstrncpy(pThreadObj->label, label, sizeof(pThreadObj->label));
-  pThreadObj->ip = ip;
-  pThreadObj->shandle = shandle;
-
-  if (pthread_mutex_init(&(pThreadObj->mutex), NULL) < 0) {
-    tError("%s failed to init TCP client mutex(%s)", label, strerror(errno));
-    free(pThreadObj);
-    terrno = TAOS_SYSTEM_ERROR(errno); 
-    return NULL;
-  }
-
-  pThreadObj->pollFd = (EpollFd)epoll_create(10);  // size does not matter
-  if (pThreadObj->pollFd < 0) {
-    tError("%s failed to create TCP client epoll", label);
-    free(pThreadObj);
-    terrno = TAOS_SYSTEM_ERROR(errno); 
-    return NULL;
-  }
-
-  pThreadObj->processData = fp;
-
  pthread_attr_init(&thattr);
  pthread_attr_setdetachstate(&thattr, PTHREAD_CREATE_JOINABLE);
-  int code = pthread_create(&(pThreadObj->thread), &thattr, taosProcessTcpData, (void *)(pThreadObj));
-  pthread_attr_destroy(&thattr);
-  if (code != 0) {
-    EpollClose(pThreadObj->pollFd);
-    pThreadObj->pollFd = -1;
-    free(pThreadObj);
-    terrno = TAOS_SYSTEM_ERROR(errno); 
-    tError("%s failed to create TCP read data thread(%s)", label, strerror(errno));
-    return NULL;
+
+  for (int i = 0; i < numOfThreads; ++i) {
+    SThreadObj *pThreadObj = (SThreadObj *)calloc(1, sizeof(SThreadObj));
+    if (pThreadObj == NULL) {
+      tError("TCP:%s no enough memory", label);
+      terrno = TAOS_SYSTEM_ERROR(errno); 
+      for (int j=0; j<i; ++j) free(pClientObj->pThreadObj[j]);
+      free(pClientObj);
+      pthread_attr_destroy(&thattr);
+      return NULL;
+    }
+    pClientObj->pThreadObj[i] = pThreadObj;
+    taosResetPthread(&pThreadObj->thread);
+    pThreadObj->ip      = ip;
+    pThreadObj->stop    = false;
+    tstrncpy(pThreadObj->label, label, sizeof(pThreadObj->label));
+    pThreadObj->shandle = shandle;
+    pThreadObj->processData = fp;
  }

-  tDebug("%s TCP client is initialized, ip:%u:%hu", label, ip, port);
+  // initialize mutex, thread, fd which may fail
+  for (int i = 0; i < numOfThreads; ++i) {
+    SThreadObj *pThreadObj = pClientObj->pThreadObj[i];
+    code = pthread_mutex_init(&(pThreadObj->mutex), NULL);
+    if (code < 0) {
+      tError("%s failed to init TCP process data mutex(%s)", label, strerror(errno));
+      break;
+    }

-  return pThreadObj;
+    pThreadObj->pollFd = (int64_t)epoll_create(10);  // size does not matter
+    if (pThreadObj->pollFd < 0) {
+      tError("%s failed to create TCP epoll", label);
+      code = -1;
+      break;
+    }
+
+    code = pthread_create(&(pThreadObj->thread), &thattr, taosProcessTcpData, (void *)(pThreadObj));
+    if (code != 0) {
+      tError("%s failed to create TCP process data thread(%s)", label, strerror(errno));
+      break;
+    }
+    pThreadObj->threadId = i;
+  }
+  if (code != 0) {
+    terrno = TAOS_SYSTEM_ERROR(errno); 
+    taosCleanUpTcpClient(pClientObj);
+    pClientObj = NULL;
+  } 
+  return pClientObj; 
 }

 void taosStopTcpClient(void *chandle) {
@ -335,15 +371,23 @@ void taosStopTcpClient(void *chandle) {
 }

 void taosCleanUpTcpClient(void *chandle) {
-  SThreadObj *pThreadObj = chandle;
-  if (pThreadObj == NULL) return;
-
-  tDebug ("%s TCP client will be cleaned up", pThreadObj->label);
-  taosStopTcpThread(pThreadObj);
+  SClientObj *pClientObj = chandle;
+  if (pClientObj == NULL) return;
+  for (int i = 0; i < pClientObj->numOfThreads; ++i) { 
+    SThreadObj *pThreadObj= pClientObj->pThreadObj[i];
+    taosStopTcpThread(pThreadObj); 
+  }
+  
+  tDebug("%s TCP client is cleaned up", pClientObj->label);
+  tfree(pClientObj->pThreadObj);
+  tfree(pClientObj);   
 }

 void *taosOpenTcpClientConnection(void *shandle, void *thandle, uint32_t ip, uint16_t port) {
-  SThreadObj *    pThreadObj = shandle;
+  SClientObj *    pClientObj = shandle;
+  int32_t index = atomic_load_32(&pClientObj->index) % pClientObj->numOfThreads;
+    atomic_store_32(&pClientObj->index, index + 1); 
+  SThreadObj *pThreadObj = pClientObj->pThreadObj[index];

  SOCKET fd = taosOpenTcpClientSocket(ip, port, pThreadObj->ip);
  if (fd <= 0) return NULL;
--- a/src/vnode/src/vnodeCfg.c
+++ b/src/vnode/src/vnodeCfg.c
@ -341,7 +341,7 @@ int32_t vnodeWriteCfg(SCreateVnodeMsg *pMsg) {
  len += snprintf(content + len, maxLen - len, "}\n");

  fwrite(content, 1, len, fp);
-  fflush(fp);
+  fsync(fileno(fp));
  fclose(fp);
  free(content);
  terrno = 0;
--- a/src/vnode/src/vnodeVersion.c
+++ b/src/vnode/src/vnodeVersion.c
@ -90,7 +90,7 @@ int32_t vnodeSaveVersion(SVnodeObj *pVnode) {
  len += snprintf(content + len, maxLen - len, "}\n");

  fwrite(content, 1, len, fp);
-  fflush(fp);
+  fsync(fileno(fp));
  fclose(fp);
  free(content);
  terrno = 0;
--- a/tests/examples/JDBC/JDBCDemo/pom.xml
+++ b/tests/examples/JDBC/JDBCDemo/pom.xml
@ -50,6 +50,7 @@
                <configuration>
                    <source>8</source>
                    <target>8</target>
+                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>

--- a/tests/examples/JDBC/SpringJdbcTemplate/pom.xml
+++ b/tests/examples/JDBC/SpringJdbcTemplate/pom.xml
@ -47,7 +47,7 @@
        <dependency>
            <groupId>com.taosdata.jdbc</groupId>
            <artifactId>taos-jdbcdriver</artifactId>
-            <version>2.0.4</version>
+            <version>2.0.18</version>
        </dependency>

    </dependencies>
@ -69,7 +69,7 @@
                <configuration>
                    <archive>
                        <manifest>
-                            <mainClass>com.taosdata.jdbc.example.jdbcTemplate.App</mainClass>
+                            <mainClass>com.taosdata.example.jdbcTemplate.App</mainClass>
                        </manifest>
                    </archive>
                    <descriptorRefs>
--- a/tests/examples/JDBC/SpringJdbcTemplate/readme.md
+++ b/tests/examples/JDBC/SpringJdbcTemplate/readme.md
@ -8,18 +8,16 @@
 修改 `src/main/resources/applicationContext.xml` 文件中 TDengine 的配置信息：

 ```xml
+<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
+    <property name="driverClassName" value="com.taosdata.jdbc.TSDBDriver"></property>
+    <property name="url" value="jdbc:TAOS://127.0.0.1:6030/log"></property>
+    <property name="username" value="root"></property>
+    <property name="password" value="taosdata"></property>
+</bean>

- <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
-        <property name="driverClassName" value="com.taosdata.jdbc.TSDBDriver"></property>
-        <property name="url" value="jdbc:TAOS://127.0.0.1:6030/log"></property>
-        <property name="username" value="root"></property>
-        <property name="password" value="taosdata"></property>
-    </bean>
-
-
-    <bean id = "jdbcTemplate"  class="org.springframework.jdbc.core.JdbcTemplate" >
-        <property name="dataSource" ref = "dataSource" ></property>
-    </bean>
+<bean id = "jdbcTemplate"  class="org.springframework.jdbc.core.JdbcTemplate" >
+    <property name="dataSource" ref = "dataSource" ></property>
+</bean>
 ```

 ### 打包运行
--- a/tests/examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/jdbc/example/jdbcTemplate/App.java
+++ b/tests/examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/jdbc/example/jdbcTemplate/App.java
@ -1,9 +1,9 @@
-package com.taosdata.jdbc.example.jdbcTemplate;
+package com.taosdata.example.jdbcTemplate;


-import com.taosdata.jdbc.example.jdbcTemplate.dao.ExecuteAsStatement;
-import com.taosdata.jdbc.example.jdbcTemplate.dao.WeatherDao;
-import com.taosdata.jdbc.example.jdbcTemplate.domain.Weather;
+import com.taosdata.example.jdbcTemplate.dao.ExecuteAsStatement;
+import com.taosdata.example.jdbcTemplate.dao.WeatherDao;
+import com.taosdata.example.jdbcTemplate.domain.Weather;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.support.ClassPathXmlApplicationContext;

--- a/tests/examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/jdbc/example/jdbcTemplate/dao/ExecuteAsStatement.java
+++ b/tests/examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/jdbc/example/jdbcTemplate/dao/ExecuteAsStatement.java
@ -1,4 +1,4 @@
-package com.taosdata.jdbc.example.jdbcTemplate.dao;
+package com.taosdata.example.jdbcTemplate.dao;

 public interface ExecuteAsStatement{

--- a/tests/examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/jdbc/example/jdbcTemplate/dao/impl/ExecuteAsStatementImpl.java
+++ b/tests/examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/jdbc/example/jdbcTemplate/dao/impl/ExecuteAsStatementImpl.java
@ -1,6 +1,5 @@
-package com.taosdata.jdbc.example.jdbcTemplate.dao.impl;
+package com.taosdata.example.jdbcTemplate.dao;

-import com.taosdata.jdbc.example.jdbcTemplate.dao.ExecuteAsStatement;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.stereotype.Repository;
--- a/tests/examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/jdbc/example/jdbcTemplate/dao/WeatherDao.java
+++ b/tests/examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/jdbc/example/jdbcTemplate/dao/WeatherDao.java
@ -1,6 +1,6 @@
-package com.taosdata.jdbc.example.jdbcTemplate.dao;
+package com.taosdata.example.jdbcTemplate.dao;

-import com.taosdata.jdbc.example.jdbcTemplate.domain.Weather;
+import com.taosdata.example.jdbcTemplate.domain.Weather;

 import java.util.List;

--- a/tests/examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/jdbc/example/jdbcTemplate/dao/impl/WeatherDaoImpl.java
+++ b/tests/examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/jdbc/example/jdbcTemplate/dao/impl/WeatherDaoImpl.java
@ -1,20 +1,16 @@
-package com.taosdata.jdbc.example.jdbcTemplate.dao.impl;
+package com.taosdata.example.jdbcTemplate.dao;

-import com.taosdata.jdbc.example.jdbcTemplate.dao.WeatherDao;
-import com.taosdata.jdbc.example.jdbcTemplate.domain.Weather;
+import com.taosdata.example.jdbcTemplate.domain.Weather;
+import com.taosdata.example.jdbcTemplate.dao.WeatherDao;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.jdbc.core.BatchPreparedStatementSetter;
 import org.springframework.jdbc.core.JdbcTemplate;
-import org.springframework.jdbc.core.namedparam.SqlParameterSourceUtils;
-import org.springframework.jdbc.core.simple.SimpleJdbcInsert;
 import org.springframework.stereotype.Repository;

 import java.sql.PreparedStatement;
 import java.sql.SQLException;
 import java.sql.Timestamp;
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;

@Repository
 public class WeatherDaoImpl implements WeatherDao {
--- a/tests/examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/jdbc/example/jdbcTemplate/domain/Weather.java
+++ b/tests/examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/jdbc/example/jdbcTemplate/domain/Weather.java
@ -1,4 +1,4 @@
-package com.taosdata.jdbc.example.jdbcTemplate.domain;
+package com.taosdata.example.jdbcTemplate.domain;

 import java.sql.Timestamp;

--- a/tests/examples/JDBC/SpringJdbcTemplate/src/main/resources/applicationContext.xml
+++ b/tests/examples/JDBC/SpringJdbcTemplate/src/main/resources/applicationContext.xml
@ -10,7 +10,7 @@

    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.taosdata.jdbc.TSDBDriver"></property>
-        <property name="url" value="jdbc:TAOS://192.168.236.137:6030/"></property>
+        <property name="url" value="jdbc:TAOS://127.0.0.1:6030/"></property>
        <property name="username" value="root"></property>
        <property name="password" value="taosdata"></property>
    </bean>
@ -20,6 +20,6 @@
        <property name="dataSource" ref="dataSource"></property>
    </bean>

-    <context:component-scan base-package="com.taosdata.jdbc.example.jdbcTemplate"/>
+    <context:component-scan base-package="com.taosdata.example.jdbcTemplate"/>

 </beans>
--- a/tests/examples/JDBC/SpringJdbcTemplate/src/test/java/com/taosdata/jdbc/example/jdbcTemplate/BatcherInsertTest.java
+++ b/tests/examples/JDBC/SpringJdbcTemplate/src/test/java/com/taosdata/jdbc/example/jdbcTemplate/BatcherInsertTest.java
@ -1,9 +1,9 @@
-package com.taosdata.jdbc.example.jdbcTemplate;
+package com.taosdata.example.jdbcTemplate;


-import com.taosdata.jdbc.example.jdbcTemplate.dao.ExecuteAsStatement;
-import com.taosdata.jdbc.example.jdbcTemplate.dao.WeatherDao;
-import com.taosdata.jdbc.example.jdbcTemplate.domain.Weather;
+import com.taosdata.example.jdbcTemplate.dao.ExecuteAsStatement;
+import com.taosdata.example.jdbcTemplate.dao.WeatherDao;
+import com.taosdata.example.jdbcTemplate.domain.Weather;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
--- a/tests/examples/JDBC/SpringJdbcTemplate/src/test/java/com/taosdata/jdbc/AppTest.java
+++ b/tests/examples/JDBC/SpringJdbcTemplate/src/test/java/com/taosdata/jdbc/AppTest.java
@ -1,18 +0,0 @@
-package com.taosdata.jdbc;
-
-import static org.junit.Assert.assertTrue;
-
-import org.junit.Test;
-
-/**
- * Unit test for simple App.
- */
-public class AppTest {
-    /**
-     * Rigorous Test :-)
-     */
-    @Test
-    public void shouldAnswerWithTrue() {
-        assertTrue(true);
-    }
-}
--- a/tests/examples/JDBC/readme.md
+++ b/tests/examples/JDBC/readme.md
@ -0,0 +1,13 @@
+# TDengine examples
+
+| No.  |        Name        | Describe                                                     |
+| :--: | :----------------: | ------------------------------------------------------------ |
+|  1   |      JDBCDemo      | Example codes for JDBC-JNI, JDBC-RESTful, Subscribe          |
+|  2   |  connectionPools   | Example codes for HikariCP, Druid, dbcp, c3p0 connection pools |
+|  3   | SpringJdbcTemplate | Example codes for spring jdbcTemplate                        |
+|  4   |  mybatisplus-demo  | Example codes for mybatis                                    |
+|  5   |   springbootdemo   | Example codes for springboot                                 |
+|  6   |      taosdemo      | This is an internal tool for testing Our JDBC-JNI, JDBC-RESTful, RESTful interfaces |
+
+
+more detail: https://www.taosdata.com/cn//documentation20/connector-java/
--- a/tests/script/general/parser/dbtbnameValidate.sim
+++ b/tests/script/general/parser/dbtbnameValidate.sim
@ -26,11 +26,11 @@ sql use ' XYZ '

 sql drop database 'abc123'
 sql drop database '_ab1234'
-sql drop database 'ABC123'
+sql_error drop database 'ABC123'
 sql drop database '_ABC123'
 sql drop database 'aABb123'
 sql drop database ' xyz '
-sql drop database ' XYZ '
+sql_error drop database ' XYZ '


 sql use abc
@ -67,9 +67,9 @@ sql describe mt
 sql describe sub_001
 sql describe sub_dy_tbl

-sql_error describe Dd
-sql_error describe FF
-sql_error describe gG
+sql describe Dd
+sql describe FF
+sql describe gG

 sql drop table abc.cc
 sql drop table  'abc.Dd'
@ -119,4 +119,4 @@ if $rows != 4 then
  return -1
 endi

-system sh/exec.sh -n dnode1 -s stop -x SIGINT
+system sh/exec.sh -n dnode1 -s stop -x SIGINT
--- a/tests/test-all.sh
+++ b/tests/test-all.sh
@ -155,7 +155,7 @@ if [ "$2" != "python" ]; then
  elif [ "$1" == "b1" ]; then
    echo "### run TSIM b1 test ###"
    runSimCaseOneByOne jenkins/basic_1.txt
-    # runSimCaseOneByOne jenkins/basic_4.txt
+    runSimCaseOneByOne jenkins/basic_4.txt
  elif [ "$1" == "b2" ]; then
    echo "### run TSIM b2 test ###"
    runSimCaseOneByOne jenkins/basic_2.txt