diff --git a/src/client/src/tscAsync.c b/src/client/src/tscAsync.c
index d857d00e15..3c5036cc1a 100644
--- a/src/client/src/tscAsync.c
+++ b/src/client/src/tscAsync.c
@@ -493,9 +493,6 @@ void tscTableMetaCallBack(void *param, TAOS_RES *res, int code) {
     return;
   }
 
-  taosReleaseRef(tscObjRef, pSql->self);
-  return;
-
   _error:
   pRes->code = code;
   tscAsyncResultOnError(pSql);
diff --git a/src/client/src/tscLocal.c b/src/client/src/tscLocal.c
index d1a325be35..e49f4e33ae 100644
--- a/src/client/src/tscLocal.c
+++ b/src/client/src/tscLocal.c
@@ -851,15 +851,19 @@ static int32_t tscProcessServStatus(SSqlObj *pSql) {
   SSqlObj* pHb = (SSqlObj*)taosAcquireRef(tscObjRef, pObj->hbrid);
   if (pHb != NULL) {
     pSql->res.code = pHb->res.code;
-    taosReleaseRef(tscObjRef, pObj->hbrid);
   }
 
   if (pSql->res.code == TSDB_CODE_RPC_NETWORK_UNAVAIL) {
+    taosReleaseRef(tscObjRef, pObj->hbrid);
     return pSql->res.code;
   }
 
-  pSql->res.code = checkForOnlineNode(pHb);
+  if (pHb != NULL) {
+    pSql->res.code = checkForOnlineNode(pHb);
+  }
+
   if (pSql->res.code == TSDB_CODE_RPC_NETWORK_UNAVAIL) {
+    taosReleaseRef(tscObjRef, pObj->hbrid);
     return pSql->res.code;
   }
 
diff --git a/src/client/src/tscParseInsert.c b/src/client/src/tscParseInsert.c
index f24f7a7ecb..8ecc58eb55 100644
--- a/src/client/src/tscParseInsert.c
+++ b/src/client/src/tscParseInsert.c
@@ -2105,7 +2105,7 @@ static void parseFileSendDataBlock(void *param, TAOS_RES *tres, int32_t numOfRow
       pParentSql->fp = pParentSql->fetchFp;
 
       // all data has been sent to vnode, call user function
-      int32_t v = (code != TSDB_CODE_SUCCESS) ? code : (int32_t)pParentSql->res.numOfRows;
+      int32_t v = (int32_t)pParentSql->res.numOfRows;
       (*pParentSql->fp)(pParentSql->param, pParentSql, v);
       return;
     }
diff --git a/src/client/src/tscParseLineProtocol.c b/src/client/src/tscParseLineProtocol.c
index f0e5017355..4b5416c6b9 100644
--- a/src/client/src/tscParseLineProtocol.c
+++ b/src/client/src/tscParseLineProtocol.c
@@ -438,10 +438,6 @@ int32_t loadTableMeta(TAOS* taos, char* tableName, SSmlSTableSchema* schema) {
   char  fullTableName[TSDB_TABLE_FNAME_LEN] = {0};
   memset(fullTableName, 0, tListLen(fullTableName));
   tNameExtractFullName(&sname, fullTableName);
-  if (code != TSDB_CODE_SUCCESS) {
-    tscFreeSqlObj(pSql);
-    return code;
-  }
   tscFreeSqlObj(pSql);
 
   schema->tags = taosArrayInit(8, sizeof(SSchema));
diff --git a/src/client/src/tscPrepare.c b/src/client/src/tscPrepare.c
index efdc24c899..9ff3a0e2dd 100644
--- a/src/client/src/tscPrepare.c
+++ b/src/client/src/tscPrepare.c
@@ -1773,7 +1773,9 @@ int taos_stmt_close(TAOS_STMT* stmt) {
       }
       tscDestroyDataBlock(pStmt->mtb.lastBlock, rmMeta);
       pStmt->mtb.pTableBlockHashList = tscDestroyBlockHashTable(pStmt->mtb.pTableBlockHashList, rmMeta);
-      taosHashCleanup(pStmt->pSql->cmd.insertParam.pTableBlockHashList);
+      if (pStmt->pSql){
+        taosHashCleanup(pStmt->pSql->cmd.insertParam.pTableBlockHashList);
+      }
       pStmt->pSql->cmd.insertParam.pTableBlockHashList = NULL;
       taosArrayDestroy(pStmt->mtb.tags);
       tfree(pStmt->mtb.sqlstr);
diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 2d5a3d524e..1fac9c9a40 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -6860,7 +6860,8 @@ static int32_t doAddGroupbyColumnsOnDemand(SSqlCmd* pCmd, SQueryInfo* pQueryInfo
     tagSchema = tscGetTableTagSchema(pTableMetaInfo->pTableMeta);
   }
 
-  SSchema* s = NULL;
+  SSchema tmp = {.type = 0, .name = "", .colId = 0, .bytes = 0};
+  SSchema* s = &tmp;
 
   for (int32_t i = 0; i < pQueryInfo->groupbyExpr.numOfGroupCols; ++i) {
     SColIndex* pColIndex = taosArrayGet(pQueryInfo->groupbyExpr.columnInfo, i);
@@ -6870,7 +6871,9 @@ static int32_t doAddGroupbyColumnsOnDemand(SSqlCmd* pCmd, SQueryInfo* pQueryInfo
       s = tGetTbnameColumnSchema();
     } else {
       if (TSDB_COL_IS_TAG(pColIndex->flag)) {
-        s = &tagSchema[colIndex];
+        if(tagSchema){
+          s = &tagSchema[colIndex];
+        }
       } else {
         s = &pSchema[colIndex];
       }
@@ -8276,17 +8279,16 @@ static int32_t doLoadAllTableMeta(SSqlObj* pSql, SQueryInfo* pQueryInfo, SSqlNod
 
     const char* name = tNameGetTableName(&pTableMetaInfo->name);
     STableMetaVgroupInfo* p = taosHashGet(pCmd->pTableMetaMap, name, strlen(name));
-
+    if(!p){
+      tscError("taosHashGet meta null. name:%s", name);
+      return TSDB_CODE_TSC_APP_ERROR;
+    }
     pTableMetaInfo->pTableMeta = tscTableMetaDup(p->pTableMeta);
     assert(pTableMetaInfo->pTableMeta != NULL);
 
     if (p->pVgroupInfo != NULL) {
       pTableMetaInfo->vgroupList = tscVgroupsInfoDup(p->pVgroupInfo);
     }
-
-    if (code != TSDB_CODE_SUCCESS) {
-      return code;
-    }
   }
 
   return TSDB_CODE_SUCCESS;
diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index 401e65efd4..0748780e1a 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -691,7 +691,9 @@ static char *doSerializeTableInfo(SQueryTableMsg *pQueryMsg, SSqlObj *pSql, STab
       tscDumpEpSetFromVgroupInfo(&pSql->epSet, &vgroupInfo);
     }
 
-    pSql->epSet.inUse = rand()%pSql->epSet.numOfEps;
+    if (pSql->epSet.numOfEps > 0){
+      pSql->epSet.inUse = rand()%pSql->epSet.numOfEps;
+    }
     pQueryMsg->head.vgId = htonl(vgId);
 
     STableIdInfo *pTableIdInfo = (STableIdInfo *)pMsg;
@@ -968,7 +970,7 @@ int tscBuildQueryMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
     }
   }
 
-  if (query.numOfTags > 0) {
+  if (query.numOfTags > 0 && query.tagColList != NULL) {
     for (int32_t i = 0; i < query.numOfTags; ++i) {
       SColumnInfo* pTag = &query.tagColList[i];
 
@@ -2351,6 +2353,9 @@ int tscProcessSTableVgroupRsp(SSqlObj *pSql) {
       break;
     }
 
+    if (!pInfo){
+      continue;
+    }
     int32_t size = 0;
     pInfo->vgroupList = createVgroupInfoFromMsg(pMsg, &size, pSql->self);
     pMsg += size;
diff --git a/src/client/src/tscStream.c b/src/client/src/tscStream.c
index da5bdf669f..a4d314cb42 100644
--- a/src/client/src/tscStream.c
+++ b/src/client/src/tscStream.c
@@ -271,7 +271,7 @@ static void tscProcessStreamRetrieveResult(void *param, TAOS_RES *res, int numOf
 
   if (pSql == NULL || numOfRows < 0) {
     int64_t retryDelayTime = tscGetRetryDelayTime(pStream, pStream->interval.sliding, pStream->precision);
-    tscError("0x%"PRIx64" stream:%p, retrieve data failed, code:0x%08x, retry in %" PRId64 " ms", pSql->self, pStream, numOfRows, retryDelayTime);
+    tscError("stream:%p, retrieve data failed, code:0x%08x, retry in %" PRId64 " ms", pStream, numOfRows, retryDelayTime);
   
     tscSetRetryTimer(pStream, pStream->pSql, retryDelayTime);
     return;
diff --git a/src/client/src/tscSubquery.c b/src/client/src/tscSubquery.c
index 73794a3aa4..bef5992d53 100644
--- a/src/client/src/tscSubquery.c
+++ b/src/client/src/tscSubquery.c
@@ -2723,6 +2723,9 @@ void tscHandleSubqueryError(SRetrieveSupport *trsupport, SSqlObj *pSql, int numO
 }
 
 static void tscAllDataRetrievedFromDnode(SRetrieveSupport *trsupport, SSqlObj* pSql) {
+  if (trsupport->pExtMemBuffer == NULL){
+    return;
+  }
   int32_t           idx = trsupport->subqueryIndex;
   SSqlObj *         pParentSql = trsupport->pParentSql;
   tOrderDescriptor *pDesc = trsupport->pOrderDescriptor;
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index 08950b93e3..7e36cce50e 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -275,16 +275,6 @@ bool tscIsProjectionQuery(SQueryInfo* pQueryInfo) {
         f != TSDB_FUNC_DERIVATIVE) {
       return false;
     }
-
-    if (f < 0) {
-      SUdfInfo* pUdfInfo = taosArrayGet(pQueryInfo->pUdfInfo, -1 * f - 1);
-      if (pUdfInfo->funcType == TSDB_UDF_TYPE_AGGREGATE) {
-        return false;
-      }
-
-      continue;
-    }
-
   }
 
   return true;
@@ -3420,7 +3410,7 @@ STableMetaInfo* tscAddTableMetaInfo(SQueryInfo* pQueryInfo, SName* name, STableM
     return NULL;
   }
 
-  if (pTagCols != NULL) {
+  if (pTagCols != NULL && pTableMetaInfo->pTableMeta != NULL) {
     tscColumnListCopy(pTableMetaInfo->tagColList, pTagCols, pTableMetaInfo->pTableMeta->id.uid);
   }
 
@@ -3851,7 +3841,8 @@ void executeQuery(SSqlObj* pSql, SQueryInfo* pQueryInfo) {
       SSqlObj* pNew = (SSqlObj*)calloc(1, sizeof(SSqlObj));
       if (pNew == NULL) {
         terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
-        //      return NULL;
+        tscError("pNew == NULL, out of memory");
+        return;
       }
 
       pNew->pTscObj = pSql->pTscObj;
@@ -4339,7 +4330,7 @@ uint32_t tscGetTableMetaSize(STableMeta* pTableMeta) {
   assert(pTableMeta != NULL);
 
   int32_t totalCols = 0;
-  if (pTableMeta->tableInfo.numOfColumns >= 0 && pTableMeta->tableInfo.numOfTags >= 0) {
+  if (pTableMeta->tableInfo.numOfColumns >= 0) {
     totalCols = pTableMeta->tableInfo.numOfColumns + pTableMeta->tableInfo.numOfTags;
   }
   
diff --git a/src/query/inc/qTableMeta.h b/src/query/inc/qTableMeta.h
index 56eea6429f..daef726ca6 100644
--- a/src/query/inc/qTableMeta.h
+++ b/src/query/inc/qTableMeta.h
@@ -60,7 +60,7 @@ typedef struct STableComInfo {
 typedef struct STableMeta {
   int32_t        vgId;
   STableId       id;
-  uint8_t        tableType;
+  int8_t         tableType;
   char           sTableName[TSDB_TABLE_FNAME_LEN];  // super table name
   uint64_t       suid;       // super table id
   int16_t        sversion;
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index 7e3e542f5e..11624ddffc 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -30,6 +30,7 @@
 #include "tcompare.h"
 #include "tscompression.h"
 #include "qScript.h"
+#include "tscLog.h"
 
 #define IS_MASTER_SCAN(runtime)        ((runtime)->scanFlag == MASTER_SCAN)
 #define IS_REVERSE_SCAN(runtime)       ((runtime)->scanFlag == REVERSE_SCAN)
@@ -750,7 +751,7 @@ static int32_t getNumOfRowsInTimeWindow(SQueryRuntimeEnv* pRuntimeEnv, SDataBloc
   int32_t step  = GET_FORWARD_DIRECTION_FACTOR(order);
 
   if (QUERY_IS_ASC_QUERY(pQueryAttr)) {
-    if (ekey < pDataBlockInfo->window.ekey) {
+    if (ekey < pDataBlockInfo->window.ekey && pPrimaryColumn) {
       num = getForwardStepsInBlock(pDataBlockInfo->rows, searchFn, ekey, startPos, order, pPrimaryColumn);
       if (updateLastKey) { // update the last key
         item->lastKey = pPrimaryColumn[startPos + (num - 1)] + step;
@@ -762,7 +763,7 @@ static int32_t getNumOfRowsInTimeWindow(SQueryRuntimeEnv* pRuntimeEnv, SDataBloc
       }
     }
   } else {  // desc
-    if (ekey > pDataBlockInfo->window.skey) {
+    if (ekey > pDataBlockInfo->window.skey && pPrimaryColumn) {
       num = getForwardStepsInBlock(pDataBlockInfo->rows, searchFn, ekey, startPos, order, pPrimaryColumn);
       if (updateLastKey) {  // update the last key
         item->lastKey = pPrimaryColumn[startPos - (num - 1)] + step;
@@ -1299,6 +1300,10 @@ static void doWindowBorderInterpolation(SOperatorInfo* pOperatorInfo, SSDataBloc
   assert(pBlock != NULL);
   int32_t step = GET_FORWARD_DIRECTION_FACTOR(pQueryAttr->order.order);
 
+  if (pBlock->pDataBlock == NULL){
+    tscError("pBlock->pDataBlock == NULL");
+    return;
+  }
   SColumnInfoData *pColInfo = taosArrayGet(pBlock->pDataBlock, 0);
 
   TSKEY  *tsCols = (TSKEY *)(pColInfo->pData);
@@ -7540,7 +7545,7 @@ SGroupbyExpr *createGroupbyExprFromMsg(SQueryTableMsg *pQueryMsg, SColIndex *pCo
 
 int32_t doCreateFilterInfo(SColumnInfo* pCols, int32_t numOfCols, int32_t numOfFilterCols, SSingleColumnFilterInfo** pFilterInfo, uint64_t qId) {
   *pFilterInfo = calloc(1, sizeof(SSingleColumnFilterInfo) * numOfFilterCols);
-  if (pFilterInfo == NULL) {
+  if (*pFilterInfo == NULL) {
     return TSDB_CODE_QRY_OUT_OF_MEMORY;
   }
 
diff --git a/src/query/src/qPlan.c b/src/query/src/qPlan.c
index 2772e76abe..f7fddecaf8 100644
--- a/src/query/src/qPlan.c
+++ b/src/query/src/qPlan.c
@@ -40,7 +40,7 @@ static SQueryNode* createQueryNode(int32_t type, const char* name, SQueryNode**
   pNode->info.type = type;
   pNode->info.name = strdup(name);
 
-  if (pTableInfo->id.uid != 0) { // it is a true table
+  if (pTableInfo->id.uid != 0 && pTableInfo->tableName) { // it is a true table
     pNode->tableInfo.id = pTableInfo->id;
     pNode->tableInfo.tableName = strdup(pTableInfo->tableName);
   }
diff --git a/src/query/src/qResultbuf.c b/src/query/src/qResultbuf.c
index 05ecf2e9b1..63eba51d6b 100644
--- a/src/query/src/qResultbuf.c
+++ b/src/query/src/qResultbuf.c
@@ -78,8 +78,9 @@ static char* doDecompressData(void* data, int32_t srcSize, int32_t *dst, SDiskba
   }
 
   *dst = tsDecompressString(data, srcSize, 1, pResultBuf->assistBuf, pResultBuf->pageSize, ONE_STAGE_COMP, NULL, 0);
-
-  memcpy(data, pResultBuf->assistBuf, *dst);
+  if (*dst > 0) {
+    memcpy(data, pResultBuf->assistBuf, *dst);
+  }
   return data;
 }
 
diff --git a/src/query/src/qScript.c b/src/query/src/qScript.c
index 261164a84c..ed56526782 100644
--- a/src/query/src/qScript.c
+++ b/src/query/src/qScript.c
@@ -377,9 +377,11 @@ ScriptEnv* getScriptEnvFromPool() {
     return NULL;
   }  
   SListNode *pNode = tdListPopHead(pool->scriptEnvs);
-  tdListNodeGetData(pool->scriptEnvs, pNode, (void *)(&pEnv));
-  listNodeFree(pNode); 
-  
+  if (pNode){
+    tdListNodeGetData(pool->scriptEnvs, pNode, (void *)(&pEnv));
+    listNodeFree(pNode);
+  }
+
   pool->cSize--;
   pthread_mutex_unlock(&pool->mutex); 
   return pEnv; 
diff --git a/src/query/src/qSqlParser.c b/src/query/src/qSqlParser.c
index eb920b3e17..08c55d5d7e 100644
--- a/src/query/src/qSqlParser.c
+++ b/src/query/src/qSqlParser.c
@@ -142,14 +142,17 @@ tSqlExpr *tSqlExprCreateIdValue(SStrToken *pToken, int32_t optrType) {
   }
 
   if (optrType == TK_NULL) {
-    pToken->type = TSDB_DATA_TYPE_NULL;
-    tVariantCreate(&pSqlExpr->value, pToken);
+    if (pToken){
+      pToken->type = TSDB_DATA_TYPE_NULL;
+      tVariantCreate(&pSqlExpr->value, pToken);
+    }
     pSqlExpr->tokenId = optrType;
     pSqlExpr->type    = SQL_NODE_VALUE;
   } else if (optrType == TK_INTEGER || optrType == TK_STRING || optrType == TK_FLOAT || optrType == TK_BOOL) {
-    toTSDBType(pToken->type);
-
-    tVariantCreate(&pSqlExpr->value, pToken);
+    if (pToken) {
+      toTSDBType(pToken->type);
+      tVariantCreate(&pSqlExpr->value, pToken);
+    }
     pSqlExpr->tokenId = optrType;
     pSqlExpr->type    = SQL_NODE_VALUE;
   } else if (optrType == TK_NOW) {
@@ -162,9 +165,11 @@ tSqlExpr *tSqlExprCreateIdValue(SStrToken *pToken, int32_t optrType) {
   } else if (optrType == TK_VARIABLE) {
     // use nanosecond by default
     // TODO set value after getting database precision
-    int32_t ret = parseAbsoluteDuration(pToken->z, pToken->n, &pSqlExpr->value.i64, TSDB_TIME_PRECISION_NANO);
-    if (ret != TSDB_CODE_SUCCESS) {
-      terrno = TSDB_CODE_TSC_SQL_SYNTAX_ERROR;
+    if (pToken) {
+      int32_t ret = parseAbsoluteDuration(pToken->z, pToken->n, &pSqlExpr->value.i64, TSDB_TIME_PRECISION_NANO);
+      if (ret != TSDB_CODE_SUCCESS) {
+        terrno = TSDB_CODE_TSC_SQL_SYNTAX_ERROR;
+      }
     }
 
     pSqlExpr->flags  |= 1 << EXPR_FLAG_NS_TIMESTAMP;
@@ -340,8 +345,9 @@ static FORCE_INLINE int32_t tStrTokenCompare(SStrToken* left, SStrToken* right)
   return (left->type == right->type && left->n == right->n && strncasecmp(left->z, right->z, left->n) == 0) ? 0 : 1;
 }
 
+// this function is not used for temporary
 int32_t tSqlExprCompare(tSqlExpr *left, tSqlExpr *right) {
-  if ((left == NULL && right) || (left && right == NULL)) {
+  if ((left == NULL && right) || (left && right == NULL) || (left == NULL && right == NULL)) {
     return 1;
   }
 
diff --git a/src/query/src/qTableMeta.c b/src/query/src/qTableMeta.c
index d25d6b7004..f687b8aa1f 100644
--- a/src/query/src/qTableMeta.c
+++ b/src/query/src/qTableMeta.c
@@ -72,7 +72,7 @@ SSchema* tscGetColumnSchemaById(STableMeta* pTableMeta, int16_t colId) {
 }
 
 STableMeta* tscCreateTableMetaFromMsg(STableMetaMsg* pTableMetaMsg) {
-  assert(pTableMetaMsg != NULL && pTableMetaMsg->numOfColumns >= 2 && pTableMetaMsg->numOfTags >= 0);
+  assert(pTableMetaMsg != NULL && pTableMetaMsg->numOfColumns >= 2);
 
   int32_t schemaSize = (pTableMetaMsg->numOfColumns + pTableMetaMsg->numOfTags) * sizeof(SSchema);
   STableMeta* pTableMeta = calloc(1, sizeof(STableMeta) + schemaSize);
diff --git a/src/query/src/queryMain.c b/src/query/src/queryMain.c
index 0d140d5ffb..7d30f7c668 100644
--- a/src/query/src/queryMain.c
+++ b/src/query/src/queryMain.c
@@ -261,7 +261,7 @@ int32_t qRetrieveQueryResultInfo(qinfo_t qinfo, bool* buildRes, void* pRspContex
   SQInfo *pQInfo = (SQInfo *)qinfo;
 
   if (pQInfo == NULL || !isValidQInfo(pQInfo)) {
-    qError("QInfo:0x%"PRIx64" invalid qhandle", pQInfo->qId);
+    qError("QInfo invalid qhandle");
     return TSDB_CODE_QRY_INVALID_QHANDLE;
   }
 
diff --git a/src/util/inc/tlist.h b/src/util/inc/tlist.h
index 6c96ec0b13..7581904540 100644
--- a/src/util/inc/tlist.h
+++ b/src/util/inc/tlist.h
@@ -44,7 +44,7 @@ typedef struct {
 #define listNEles(l) (l)->numOfEles
 #define listEleSize(l) (l)->eleSize
 #define isListEmpty(l) ((l)->numOfEles == 0)
-#define listNodeFree(n) free(n);
+#define listNodeFree(n) free(n)
 
 SList *    tdListNew(int eleSize);
 void *     tdListFree(SList *list);