diff --git a/src/client/inc/tscUtil.h b/src/client/inc/tscUtil.h
index c858bd5867c64da4c7397aed2035119ff414d112..d183fb4a721a57011ba7c09c304d4cf8ad7180dd 100644
--- a/src/client/inc/tscUtil.h
+++ b/src/client/inc/tscUtil.h
@@ -41,6 +41,15 @@ extern "C" {
 #define UTIL_TABLE_IS_TMP_TABLE(metaInfo) \
   (((metaInfo)->pTableMeta != NULL) && ((metaInfo)->pTableMeta->tableType == TSDB_TEMP_TABLE))
 
+#define UTIL_GET_VGROUPMAP(pSql) \
+  (pSql->pTscObj->pClusterInfo->vgroupMap)
+
+#define UTIL_GET_TABLEMETA(pSql) \
+  (pSql->pTscObj->pClusterInfo->tableMetaMap)
+
+#define UTIL_GET_VGROUPLIST(pSql) \
+  (pSql->pTscObj->pClusterInfo->vgroupListBuf)
+
 #pragma pack(push,1)
 // this struct is transfered as binary, padding two bytes to avoid
 // an 'uid' whose low bytes is 0xff being recoginized as NULL,
@@ -106,10 +115,11 @@ typedef struct SBlockKeyInfo {
   SBlockKeyTuple* pKeyTuple;
 } SBlockKeyInfo;
 
+
 int32_t converToStr(char *str, int type, void *buf, int32_t bufSize, int32_t *len);
 
 int32_t tscCreateDataBlock(size_t initialSize, int32_t rowSize, int32_t startOffset, SName* name, STableMeta* pTableMeta, STableDataBlocks** dataBlocks);
-void tscDestroyDataBlock(STableDataBlocks* pDataBlock, bool removeMeta);
+void tscDestroyDataBlock(SSqlObj *pSql, STableDataBlocks* pDataBlock, bool removeMeta);
 void    tscSortRemoveDataBlockDupRowsRaw(STableDataBlocks* dataBuf);
 int     tscSortRemoveDataBlockDupRows(STableDataBlocks* dataBuf, SBlockKeyInfo* pBlkKeyInfo);
 int32_t tsSetBlockInfo(SSubmitBlk *pBlocks, const STableMeta *pTableMeta, int32_t numOfRows);
@@ -120,12 +130,12 @@ void doRetrieveSubqueryData(SSchedMsg *pMsg);
 SParamInfo* tscAddParamToDataBlock(STableDataBlocks* pDataBlock, char type, uint8_t timePrec, int16_t bytes,
                                    uint32_t offset);
 
-void*   tscDestroyBlockArrayList(SArray* pDataBlockList);
+void*   tscDestroyBlockArrayList(SSqlObj* pSql, SArray* pDataBlockList);
 void*  tscDestroyUdfArrayList(SArray* pUdfList);
-void*   tscDestroyBlockHashTable(SHashObj* pBlockHashTable, bool removeMeta);
+void*   tscDestroyBlockHashTable(SSqlObj* pSql, SHashObj* pBlockHashTable, bool removeMeta);
 
 int32_t tscCopyDataBlockToPayload(SSqlObj* pSql, STableDataBlocks* pDataBlock);
-int32_t tscMergeTableDataBlocks(SInsertStatementParam *pInsertParam, bool freeBlockMap);
+int32_t tscMergeTableDataBlocks(SSqlObj *pSql, SInsertStatementParam *pInsertParam, bool freeBlockMap);
 int32_t tscGetDataBlockFromList(SHashObj* pHashList, int64_t id, int32_t size, int32_t startOffset, int32_t rowSize, SName* pName, STableMeta* pTableMeta,
                                 STableDataBlocks** dataBlocks, SArray* pBlockList);
 
@@ -353,7 +363,7 @@ STableMeta* createSuperTableMeta(STableMetaMsg* pChild);
 uint32_t tscGetTableMetaSize(STableMeta* pTableMeta);
 CChildTableMeta* tscCreateChildMeta(STableMeta* pTableMeta);
 uint32_t tscGetTableMetaMaxSize();
-int32_t tscCreateTableMetaFromSTableMeta(STableMeta** ppChild, const char* name, size_t *tableMetaCapacity, STableMeta **ppStable);
+int32_t tscCreateTableMetaFromSTableMeta(SSqlObj *pSql, STableMeta** ppChild, const char* name, size_t *tableMetaCapacity, STableMeta **ppStable);
 STableMeta* tscTableMetaDup(STableMeta* pTableMeta);
 SVgroupsInfo* tscVgroupsInfoDup(SVgroupsInfo* pVgroupsInfo);
 
@@ -374,6 +384,7 @@ void tscRemoveCachedTableMeta(STableMetaInfo* pTableMetaInfo, uint64_t id);
 
 char* cloneCurrentDBName(SSqlObj* pSql);
 
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/client/inc/tsclient.h b/src/client/inc/tsclient.h
index dd4ff7eb57f20cfc8d31328630fbb14b7acf7017..eebb471e305132fa5b3b403d149d449d36072ab2 100644
--- a/src/client/inc/tsclient.h
+++ b/src/client/inc/tsclient.h
@@ -48,6 +48,7 @@ struct SSqlInfo;
 
 typedef void (*__async_cb_func_t)(void *param, TAOS_RES *tres, int32_t numOfRows);
 
+
 typedef struct SNewVgroupInfo {
   int32_t    vgId;
   int8_t     inUse;
@@ -139,6 +140,13 @@ typedef enum {
   ROW_COMPARE_NEED = 1,
 } ERowCompareStat;
 
+typedef struct {
+  void *vgroupMap;  
+  void *tableMetaMap;
+  void *vgroupListBuf; 
+  int64_t ref;
+} SClusterInfo;
+
 int tsParseTime(SStrToken *pToken, int64_t *time, char **next, char *error, int16_t timePrec);
 
 int  initMemRowBuilder(SMemRowBuilder *pBuilder, uint32_t nRows, uint32_t nCols, uint32_t nBoundCols,
@@ -324,6 +332,7 @@ typedef struct STscObj {
   char               acctId[TSDB_ACCT_ID_LEN];
   char               db[TSDB_ACCT_ID_LEN + TSDB_DB_NAME_LEN];
   char               sversion[TSDB_VERSION_LEN];
+  char               clusterId[TSDB_CLUSTER_ID_LEN];
   char               writeAuth : 1;
   char               superAuth : 1;
   uint32_t           connId;
@@ -332,9 +341,11 @@ typedef struct STscObj {
   struct SSqlObj *   sqlList;
   struct SSqlStream *streamList;
   SRpcObj           *pRpcObj;
+  SClusterInfo       *pClusterInfo;
   SRpcCorEpSet      *tscCorMgmtEpSet;
   pthread_mutex_t    mutex;
   int32_t            numOfObj; // number of sqlObj from this tscObj
+      
   SReqOrigin         from;
 } STscObj;
 
@@ -417,6 +428,9 @@ int  tscAcquireRpc(const char *key, const char *user, const char *secret,void **
 void tscReleaseRpc(void *param);
 void tscInitMsgsFp();
 
+void *tscAcquireClusterInfo(const char *clusterId);
+void tscReleaseClusterInfo(const char *clusterId);
+
 int tsParseSql(SSqlObj *pSql, bool initial);
 
 void tscProcessMsgFromServer(SRpcMsg *rpcMsg, SRpcEpSet *pEpSet);
diff --git a/src/client/src/tscLocal.c b/src/client/src/tscLocal.c
index 07db18b498873f4a023d8ea76aadd7e76a4cd8d2..df9857e97e7b8cc2f3ed8543939bc30d1fe5608b 100644
--- a/src/client/src/tscLocal.c
+++ b/src/client/src/tscLocal.c
@@ -924,8 +924,8 @@ int tscProcessLocalCmd(SSqlObj *pSql) {
   } else if (pCmd->command == TSDB_SQL_SHOW_CREATE_DATABASE) {
     pRes->code = tscProcessShowCreateDatabase(pSql); 
   } else if (pCmd->command == TSDB_SQL_RESET_CACHE) {
-    taosHashClear(tscTableMetaMap);
-    taosCacheEmpty(tscVgroupListBuf);
+    taosHashClear(UTIL_GET_TABLEMETA(pSql));
+    taosCacheEmpty(UTIL_GET_VGROUPLIST(pSql));
     pRes->code = TSDB_CODE_SUCCESS;
   } else if (pCmd->command == TSDB_SQL_SERV_VERSION) {
     pRes->code = tscProcessServerVer(pSql);
diff --git a/src/client/src/tscParseInsert.c b/src/client/src/tscParseInsert.c
index 1bf27e6cad1d57fdfd4b786d1cdcea981bf3333b..4e2b89d64f95a284d1e50dd1847af61ab7b6b653 100644
--- a/src/client/src/tscParseInsert.c
+++ b/src/client/src/tscParseInsert.c
@@ -1529,7 +1529,7 @@ int tsParseInsertSql(SSqlObj *pSql) {
 
   // merge according to vgId
   if (!TSDB_QUERY_HAS_TYPE(pInsertParam->insertType, TSDB_QUERY_TYPE_STMT_INSERT) && taosHashGetSize(pInsertParam->pTableBlockHashList) > 0) {
-    if ((code = tscMergeTableDataBlocks(pInsertParam, true)) != TSDB_CODE_SUCCESS) {
+    if ((code = tscMergeTableDataBlocks(pSql, pInsertParam, true)) != TSDB_CODE_SUCCESS) {
       goto _clean;
     }
   }
@@ -1635,7 +1635,7 @@ static int doPackSendDataBlock(SSqlObj* pSql, SInsertStatementParam *pInsertPara
     return tscInvalidOperationMsg(pInsertParam->msg, "too many rows in sql, total number of rows should be less than 32767", NULL);
   }
 
-  if ((code = tscMergeTableDataBlocks(pInsertParam, true)) != TSDB_CODE_SUCCESS) {
+  if ((code = tscMergeTableDataBlocks(pSql, pInsertParam, true)) != TSDB_CODE_SUCCESS) {
     return code;
   }
 
@@ -1696,7 +1696,7 @@ static void parseFileSendDataBlock(void *param, TAOS_RES *tres, int32_t numOfRow
   SInsertStatementParam *pInsertParam = &pCmd->insertParam;
   destroyTableNameList(pInsertParam);
 
-  pInsertParam->pDataBlocks = tscDestroyBlockArrayList(pInsertParam->pDataBlocks);
+  pInsertParam->pDataBlocks = tscDestroyBlockArrayList(pParentSql, pInsertParam->pDataBlocks);
 
   if (pInsertParam->pTableBlockHashList == NULL) {
     pInsertParam->pTableBlockHashList = taosHashInit(16, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BIGINT), true, false);
diff --git a/src/client/src/tscParseLineProtocol.c b/src/client/src/tscParseLineProtocol.c
index 22392ba306faeed05af5d695ca0090057ac211cf..382198e8b3e8422651b0072818a73bbd7b5c6feb 100644
--- a/src/client/src/tscParseLineProtocol.c
+++ b/src/client/src/tscParseLineProtocol.c
@@ -574,10 +574,10 @@ static int32_t retrieveTableMeta(TAOS* taos, char* tableName, STableMeta** pTabl
     char fullTableName[TSDB_TABLE_FNAME_LEN] = {0};
     memset(fullTableName, 0, tListLen(fullTableName));
     tNameExtractFullName(&sname, fullTableName);
-    tscFreeRegisteredSqlObj(pSql);
 
     size_t size = 0;
-    taosHashGetCloneExt(tscTableMetaMap, fullTableName, strlen(fullTableName), NULL, (void**)&tableMeta, &size);
+    taosHashGetCloneExt(UTIL_GET_TABLEMETA(pSql), fullTableName, strlen(fullTableName), NULL, (void**)&tableMeta, &size);
+    tscFreeRegisteredSqlObj(pSql);
   }
 
   if (tableMeta != NULL) {
diff --git a/src/client/src/tscPrepare.c b/src/client/src/tscPrepare.c
index d0ac0ccf4ee4bfa381a78090409a761717ceb4b0..f6a64cb5b1c04b461e38acce2ea1cae65dec71e6 100644
--- a/src/client/src/tscPrepare.c
+++ b/src/client/src/tscPrepare.c
@@ -1163,7 +1163,7 @@ static int insertStmtExecute(STscStmt* stmt) {
 
   fillTablesColumnsNull(stmt->pSql);
 
-  int code = tscMergeTableDataBlocks(&stmt->pSql->cmd.insertParam, false);
+  int code = tscMergeTableDataBlocks(stmt->pSql, &stmt->pSql->cmd.insertParam, false);
   if (code != TSDB_CODE_SUCCESS) {
     return code;
   }
@@ -1194,7 +1194,7 @@ static int insertStmtExecute(STscStmt* stmt) {
 
   pCmd->insertParam.numOfTables = 0;
   tfree(pCmd->insertParam.pTableNameList);
-  pCmd->insertParam.pDataBlocks = tscDestroyBlockArrayList(pCmd->insertParam.pDataBlocks);
+  pCmd->insertParam.pDataBlocks = tscDestroyBlockArrayList(pSql, pCmd->insertParam.pDataBlocks);
 
   return pSql->res.code;
 }
@@ -1215,7 +1215,7 @@ static void insertBatchClean(STscStmt* pStmt) {
 
   tfree(pCmd->insertParam.pTableNameList);
 
-  pCmd->insertParam.pDataBlocks = tscDestroyBlockArrayList(pCmd->insertParam.pDataBlocks);
+  pCmd->insertParam.pDataBlocks = tscDestroyBlockArrayList(pSql, pCmd->insertParam.pDataBlocks);
   pCmd->insertParam.numOfTables = 0;
 
   taosHashClear(pCmd->insertParam.pTableBlockHashList);
@@ -1242,7 +1242,7 @@ static int insertBatchStmtExecute(STscStmt* pStmt) {
 
   fillTablesColumnsNull(pStmt->pSql);
 
-  if ((code = tscMergeTableDataBlocks(&pStmt->pSql->cmd.insertParam, false)) != TSDB_CODE_SUCCESS) {
+  if ((code = tscMergeTableDataBlocks(pStmt->pSql, &pStmt->pSql->cmd.insertParam, false)) != TSDB_CODE_SUCCESS) {
     return code;
   }
 
@@ -1773,8 +1773,8 @@ int taos_stmt_close(TAOS_STMT* stmt) {
       if (pStmt->pSql && pStmt->pSql->res.code != 0) {
         rmMeta = true;
       }
-      tscDestroyDataBlock(pStmt->mtb.lastBlock, rmMeta);
-      pStmt->mtb.pTableBlockHashList = tscDestroyBlockHashTable(pStmt->mtb.pTableBlockHashList, rmMeta);
+      tscDestroyDataBlock(pStmt->pSql, pStmt->mtb.lastBlock, rmMeta);
+      pStmt->mtb.pTableBlockHashList = tscDestroyBlockHashTable(pStmt->pSql, pStmt->mtb.pTableBlockHashList, rmMeta);
       if (pStmt->pSql){
         taosHashCleanup(pStmt->pSql->cmd.insertParam.pTableBlockHashList);
       }
diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index a62a8ac3efca0836faab778224aa4a831e84e580..4d5bfe350aa6435ef04a9646491fe2c93a996e92 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -8280,7 +8280,7 @@ int32_t loadAllTableMeta(SSqlObj* pSql, struct SSqlInfo* pInfo) {
 
     size_t len = strlen(name);
       
-    if (NULL == taosHashGetCloneExt(tscTableMetaMap, name, len, NULL,  (void **)&pTableMeta, &tableMetaCapacity)) {
+    if (NULL == taosHashGetCloneExt(UTIL_GET_TABLEMETA(pSql), name, len, NULL,  (void **)&pTableMeta, &tableMetaCapacity)) {
       // not found
       tfree(pTableMeta);
     }
@@ -8291,7 +8291,7 @@ int32_t loadAllTableMeta(SSqlObj* pSql, struct SSqlInfo* pInfo) {
       // avoid mem leak, may should update pTableMeta
       void* pVgroupIdList = NULL;
       if (pTableMeta->tableType == TSDB_CHILD_TABLE) {
-        code = tscCreateTableMetaFromSTableMeta((STableMeta **)(&pTableMeta), name, &tableMetaCapacity, (STableMeta **)(&pSTMeta));
+        code = tscCreateTableMetaFromSTableMeta(pSql, (STableMeta **)(&pTableMeta), name, &tableMetaCapacity, (STableMeta **)(&pSTMeta));
         pSql->pBuf = (void *)pSTMeta; 
 
         // create the child table meta from super table failed, try load it from mnode
@@ -8303,7 +8303,7 @@ int32_t loadAllTableMeta(SSqlObj* pSql, struct SSqlInfo* pInfo) {
       } else if (pTableMeta->tableType == TSDB_SUPER_TABLE) {
         // the vgroup list of super table is not kept in local buffer, so here need retrieve it from the mnode each time
         tscDebug("0x%"PRIx64" try to acquire cached super table %s vgroup id list", pSql->self, name);
-        void* pv = taosCacheAcquireByKey(tscVgroupListBuf, name, len);
+        void* pv = taosCacheAcquireByKey(UTIL_GET_VGROUPLIST(pSql), name, len);
         if (pv == NULL) {
           char* t = strdup(name);
           taosArrayPush(pVgroupList, &t);
@@ -8316,7 +8316,7 @@ int32_t loadAllTableMeta(SSqlObj* pSql, struct SSqlInfo* pInfo) {
           }
 
           taosArrayAddBatch(pVgroupIdList, pdata->data, (int32_t) pdata->num);
-          taosCacheRelease(tscVgroupListBuf, &pv, false);
+          taosCacheRelease(UTIL_GET_VGROUPLIST(pSql), &pv, false);
         }
       }
 
@@ -8466,7 +8466,7 @@ static int32_t doLoadAllTableMeta(SSqlObj* pSql, SQueryInfo* pQueryInfo, SSqlNod
 
         // check if current buffer contains the vgroup info. If not, add it
         SNewVgroupInfo existVgroupInfo = {.inUse = -1,};
-        taosHashGetClone(tscVgroupMap, id, sizeof(*id), NULL, &existVgroupInfo);
+        taosHashGetClone(UTIL_GET_VGROUPMAP(pSql), id, sizeof(*id), NULL, &existVgroupInfo);
 
         assert(existVgroupInfo.inUse >= 0);
         SVgroupMsg *pVgroup = &pTableMetaInfo->vgroupList->vgroups[j];
diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index dcfbc857d5d6792b3796a098ea61046439fc5d0f..b7661d51f910dd320af95acfaae857bb51056b20 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -158,7 +158,7 @@ static void tscUpdateVgroupInfo(SSqlObj *pSql, SRpcEpSet *pEpSet) {
   assert(vgId > 0);
 
   SNewVgroupInfo vgroupInfo = {.vgId = -1};
-  taosHashGetClone(tscVgroupMap, &vgId, sizeof(vgId), NULL, &vgroupInfo);
+  taosHashGetClone(UTIL_GET_VGROUPMAP(pSql), &vgId, sizeof(vgId), NULL, &vgroupInfo);
   assert(vgroupInfo.numOfEps > 0 && vgroupInfo.vgId > 0);
 
   tscDebug("before: Endpoint in use:%d, numOfEps:%d", vgroupInfo.inUse, vgroupInfo.numOfEps);
@@ -170,7 +170,7 @@ static void tscUpdateVgroupInfo(SSqlObj *pSql, SRpcEpSet *pEpSet) {
   }
 
   tscDebug("after: EndPoint in use:%d, numOfEps:%d", vgroupInfo.inUse, vgroupInfo.numOfEps);
-  taosHashPut(tscVgroupMap, &vgId, sizeof(vgId), &vgroupInfo, sizeof(SNewVgroupInfo));
+  taosHashPut(UTIL_GET_VGROUPMAP(pSql), &vgId, sizeof(vgId), &vgroupInfo, sizeof(SNewVgroupInfo));
 
   // Update the local cached epSet info cached by SqlObj
   int32_t inUse = pSql->epSet.inUse;
@@ -654,7 +654,7 @@ int tscBuildSubmitMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
   pSql->cmd.msgType = TSDB_MSG_TYPE_SUBMIT;
 
   SNewVgroupInfo vgroupInfo = {0};
-  taosHashGetClone(tscVgroupMap, &pTableMeta->vgId, sizeof(pTableMeta->vgId), NULL, &vgroupInfo);
+  taosHashGetClone(UTIL_GET_VGROUPMAP(pSql), &pTableMeta->vgId, sizeof(pTableMeta->vgId), NULL, &vgroupInfo);
   tscDumpEpSetFromVgroupInfo(&pSql->epSet, &vgroupInfo);
 
   tscDebug("0x%"PRIx64" submit msg built, numberOfEP:%d", pSql->self, pSql->epSet.numOfEps);
@@ -737,7 +737,7 @@ static char *doSerializeTableInfo(SQueryTableMsg *pQueryMsg, SSqlObj *pSql, STab
       vgId = pTableMeta->vgId;
 
       SNewVgroupInfo vgroupInfo = {0};
-      taosHashGetClone(tscVgroupMap, &pTableMeta->vgId, sizeof(pTableMeta->vgId), NULL, &vgroupInfo);
+      taosHashGetClone(UTIL_GET_VGROUPMAP(pSql), &pTableMeta->vgId, sizeof(pTableMeta->vgId), NULL, &vgroupInfo);
       tscDumpEpSetFromVgroupInfo(&pSql->epSet, &vgroupInfo);
     }
 
@@ -1650,7 +1650,7 @@ int tscBuildUpdateTagMsg(SSqlObj* pSql, SSqlInfo *pInfo) {
   STableMeta *pTableMeta = tscGetMetaInfo(pQueryInfo, 0)->pTableMeta;
 
   SNewVgroupInfo vgroupInfo = {.vgId = -1};
-  taosHashGetClone(tscVgroupMap, &pTableMeta->vgId, sizeof(pTableMeta->vgId), NULL, &vgroupInfo);
+  taosHashGetClone(UTIL_GET_VGROUPMAP(pSql), &pTableMeta->vgId, sizeof(pTableMeta->vgId), NULL, &vgroupInfo);
   assert(vgroupInfo.vgId > 0);
 
   tscDumpEpSetFromVgroupInfo(&pSql->epSet, &vgroupInfo);
@@ -2036,21 +2036,21 @@ static int32_t tableMetaMsgConvert(STableMetaMsg* pMetaMsg) {
 }
 
 // update the vgroupInfo if needed
-static void doUpdateVgroupInfo(int32_t vgId, SVgroupMsg *pVgroupMsg) {
+static void doUpdateVgroupInfo(SSqlObj *pSql, int32_t vgId, SVgroupMsg *pVgroupMsg) {
   assert(vgId > 0);
 
   SNewVgroupInfo vgroupInfo = {.inUse = -1};
-  taosHashGetClone(tscVgroupMap, &vgId, sizeof(vgId), NULL, &vgroupInfo);
+  taosHashGetClone(UTIL_GET_VGROUPMAP(pSql), &vgId, sizeof(vgId), NULL, &vgroupInfo);
 
   // vgroup info exists, compare with it
   if (((vgroupInfo.inUse >= 0) && !vgroupInfoIdentical(&vgroupInfo, pVgroupMsg)) || (vgroupInfo.inUse < 0)) {
     vgroupInfo = createNewVgroupInfo(pVgroupMsg);
-    taosHashPut(tscVgroupMap, &vgId, sizeof(vgId), &vgroupInfo, sizeof(vgroupInfo));
-    tscDebug("add/update new VgroupInfo, vgId:%d, total cached:%d", vgId, (int32_t) taosHashGetSize(tscVgroupMap));
+    taosHashPut(UTIL_GET_VGROUPMAP(pSql), &vgId, sizeof(vgId), &vgroupInfo, sizeof(vgroupInfo));
+    tscDebug("add/update new VgroupInfo, vgId:%d, total cached:%d", vgId, (int32_t) taosHashGetSize(UTIL_GET_VGROUPMAP(pSql)));
   }
 }
 
-static void doAddTableMetaToLocalBuf(STableMeta* pTableMeta, STableMetaMsg* pMetaMsg, bool updateSTable) {
+static void doAddTableMetaToLocalBuf(SSqlObj *pSql, STableMeta* pTableMeta, STableMetaMsg* pMetaMsg, bool updateSTable) {
   if (pTableMeta->tableType == TSDB_CHILD_TABLE) {
     // add or update the corresponding super table meta data info
     int32_t len = (int32_t) strnlen(pTableMeta->sTableName, TSDB_TABLE_FNAME_LEN);
@@ -2059,18 +2059,18 @@ static void doAddTableMetaToLocalBuf(STableMeta* pTableMeta, STableMetaMsg* pMet
     if (updateSTable) {
       STableMeta* pSupTableMeta = createSuperTableMeta(pMetaMsg);
       uint32_t size = tscGetTableMetaSize(pSupTableMeta);
-      int32_t code = taosHashPut(tscTableMetaMap, pTableMeta->sTableName, len, pSupTableMeta, size);
+      int32_t code = taosHashPut(UTIL_GET_TABLEMETA(pSql), pTableMeta->sTableName, len, pSupTableMeta, size);
       assert(code == TSDB_CODE_SUCCESS);
 
       tfree(pSupTableMeta);
     }
 
     CChildTableMeta* cMeta = tscCreateChildMeta(pTableMeta);
-    taosHashPut(tscTableMetaMap, pMetaMsg->tableFname, strlen(pMetaMsg->tableFname), cMeta, sizeof(CChildTableMeta));
+    taosHashPut(UTIL_GET_TABLEMETA(pSql), pMetaMsg->tableFname, strlen(pMetaMsg->tableFname), cMeta, sizeof(CChildTableMeta));
     tfree(cMeta);
   } else {
     uint32_t s = tscGetTableMetaSize(pTableMeta);
-    taosHashPut(tscTableMetaMap, pMetaMsg->tableFname, strlen(pMetaMsg->tableFname), pTableMeta, s);
+    taosHashPut(UTIL_GET_TABLEMETA(pSql), pMetaMsg->tableFname, strlen(pMetaMsg->tableFname), pTableMeta, s);
   }
 }
 
@@ -2098,9 +2098,9 @@ int tscProcessTableMetaRsp(SSqlObj *pSql) {
   tNameExtractFullName(&pTableMetaInfo->name, name);
   assert(strncmp(pMetaMsg->tableFname, name, tListLen(pMetaMsg->tableFname)) == 0);
 
-  doAddTableMetaToLocalBuf(pTableMeta, pMetaMsg, true);
+  doAddTableMetaToLocalBuf(pSql, pTableMeta, pMetaMsg, true);
   if (pTableMeta->tableType != TSDB_SUPER_TABLE) {
-    doUpdateVgroupInfo(pTableMeta->vgId, &pMetaMsg->vgroup);
+    doUpdateVgroupInfo(pSql, pTableMeta->vgId, &pMetaMsg->vgroup);
   }
 
   tscDebug("0x%"PRIx64" recv table meta, uid:%" PRIu64 ", tid:%d, name:%s, numOfCols:%d, numOfTags:%d", pSql->self,
@@ -2111,7 +2111,7 @@ int tscProcessTableMetaRsp(SSqlObj *pSql) {
   return TSDB_CODE_SUCCESS;
 }
 
-static SArray* createVgroupIdListFromMsg(char* pMsg, SHashObj* pSet, char* name, int32_t* size, uint64_t id) {
+static SArray* createVgroupIdListFromMsg(SSqlObj *pSql, char* pMsg, SHashObj* pSet, char* name, int32_t* size, uint64_t id) {
   SVgroupsMsg *pVgroupMsg = (SVgroupsMsg *)pMsg;
 
   pVgroupMsg->numOfVgroups = htonl(pVgroupMsg->numOfVgroups);
@@ -2134,7 +2134,7 @@ static SArray* createVgroupIdListFromMsg(char* pMsg, SHashObj* pSet, char* name,
 
       if (taosHashGet(pSet, &vmsg->vgId, sizeof(vmsg->vgId)) == NULL) {
         taosHashPut(pSet, &vmsg->vgId, sizeof(vmsg->vgId), "", 0);
-        doUpdateVgroupInfo(vmsg->vgId, vmsg);
+        doUpdateVgroupInfo(pSql, vmsg->vgId, vmsg);
       }
     }
   }
@@ -2142,7 +2142,7 @@ static SArray* createVgroupIdListFromMsg(char* pMsg, SHashObj* pSet, char* name,
   return vgroupIdList;
 }
 
-static SVgroupsInfo* createVgroupInfoFromMsg(char* pMsg, int32_t* size, uint64_t id) {
+static SVgroupsInfo* createVgroupInfoFromMsg(SSqlObj *pSql, char* pMsg, int32_t* size, uint64_t id) {
   SVgroupsMsg *pVgroupMsg = (SVgroupsMsg *)pMsg;
   pVgroupMsg->numOfVgroups = htonl(pVgroupMsg->numOfVgroups);
 
@@ -2174,7 +2174,7 @@ static SVgroupsInfo* createVgroupInfoFromMsg(char* pMsg, int32_t* size, uint64_t
 //        pVgroup->epAddr[k].fqdn = strndup(vmsg->epAddr[k].fqdn, TSDB_FQDN_LEN);
       }
 
-      doUpdateVgroupInfo(pVgroup->vgId, vmsg);
+      doUpdateVgroupInfo(pSql, pVgroup->vgId, vmsg);
     }
   }
 
@@ -2309,12 +2309,12 @@ int tscProcessMultiTableMetaRsp(SSqlObj *pSql) {
     }
 
     // create the tableMeta and add it into the TableMeta map
-    doAddTableMetaToLocalBuf(pTableMeta, pMetaMsg, updateStableMeta);
+    doAddTableMetaToLocalBuf(pParentSql, pTableMeta, pMetaMsg, updateStableMeta);
 
     // for each vgroup, only update the information once.
     int64_t vgId = pMetaMsg->vgroup.vgId;
     if (pTableMeta->tableType != TSDB_SUPER_TABLE && taosHashGet(pSet, &vgId, sizeof(vgId)) == NULL) {
-      doUpdateVgroupInfo((int32_t) vgId, &pMetaMsg->vgroup);
+      doUpdateVgroupInfo(pParentSql, (int32_t) vgId, &pMetaMsg->vgroup);
       taosHashPut(pSet, &vgId, sizeof(vgId), "", 0);
     }
 
@@ -2339,7 +2339,7 @@ int tscProcessMultiTableMetaRsp(SSqlObj *pSql) {
       taosArrayDestroy(p->vgroupIdList);
     }
 
-    p->vgroupIdList = createVgroupIdListFromMsg(pMsg, pSet, fname, &size, pSql->self);
+    p->vgroupIdList = createVgroupIdListFromMsg(pParentSql, pMsg, pSet, fname, &size, pSql->self);
 
     int32_t numOfVgId = (int32_t) taosArrayGetSize(p->vgroupIdList);
     int32_t s = sizeof(tFilePage) + numOfVgId * sizeof(int32_t);
@@ -2348,8 +2348,8 @@ int tscProcessMultiTableMetaRsp(SSqlObj *pSql) {
     idList->num = numOfVgId;
     memcpy(idList->data, TARRAY_GET_START(p->vgroupIdList), numOfVgId * sizeof(int32_t));
 
-    void* idListInst = taosCachePut(tscVgroupListBuf, fname, len, idList, s, 5000);
-    taosCacheRelease(tscVgroupListBuf, (void*) &idListInst, false);
+    void* idListInst = taosCachePut(UTIL_GET_VGROUPLIST(pParentSql), fname, len, idList, s, 5000);
+    taosCacheRelease(UTIL_GET_VGROUPLIST(pParentSql), (void*) &idListInst, false);
 
     tfree(idList);
     pMsg += size;
@@ -2439,7 +2439,7 @@ int tscProcessSTableVgroupRsp(SSqlObj *pSql) {
       continue;
     }
     int32_t size = 0;
-    pInfo->vgroupList = createVgroupInfoFromMsg(pMsg, &size, pSql->self);
+    pInfo->vgroupList = createVgroupInfoFromMsg(parent, pMsg, &size, pSql->self);
     pMsg += size;
   }
 
@@ -2570,7 +2570,8 @@ int tscProcessConnectRsp(SSqlObj *pSql) {
   pObj->writeAuth = pConnect->writeAuth;
   pObj->superAuth = pConnect->superAuth;
   pObj->connId = htonl(pConnect->connId);
-
+  tstrncpy(pObj->clusterId, pConnect->clusterId, sizeof(pObj->clusterId));  
+  
   createHbObj(pObj);
 
   //launch a timer to send heartbeat to maintain the connection and send status to mnode
@@ -2595,9 +2596,9 @@ int tscProcessDropDbRsp(SSqlObj *pSql) {
   //TODO LOCK DB WHEN MODIFY IT
   //pSql->pTscObj->db[0] = 0;
   
-  taosHashClear(tscTableMetaMap);
-  taosHashClear(tscVgroupMap);
-  taosCacheEmpty(tscVgroupListBuf);
+  taosHashClear(UTIL_GET_TABLEMETA(pSql));
+  taosHashClear(UTIL_GET_VGROUPMAP(pSql));
+  taosCacheEmpty(UTIL_GET_VGROUPLIST(pSql));
   return 0;
 }
 
@@ -2617,7 +2618,7 @@ int tscProcessAlterTableMsgRsp(SSqlObj *pSql) {
   tscDebug("0x%"PRIx64" remove tableMeta in hashMap after alter-table: %s", pSql->self, name);
 
   bool isSuperTable = UTIL_TABLE_IS_SUPER_TABLE(pTableMetaInfo);
-  taosHashRemove(tscTableMetaMap, name, strnlen(name, TSDB_TABLE_FNAME_LEN));
+  taosHashRemove(UTIL_GET_TABLEMETA(pSql), name, strnlen(name, TSDB_TABLE_FNAME_LEN));
   tfree(pTableMetaInfo->pTableMeta);
 
   if (isSuperTable) {  // if it is a super table, iterate the hashTable and remove all the childTableMeta
@@ -2932,7 +2933,7 @@ int32_t tscGetTableMetaImpl(SSqlObj* pSql, STableMetaInfo *pTableMetaInfo, bool
     memset(pTableMetaInfo->pTableMeta, 0, pTableMetaInfo->tableMetaCapacity);
   }
 
-  if (NULL == taosHashGetCloneExt(tscTableMetaMap, name, len, NULL, (void **)&(pTableMetaInfo->pTableMeta), &pTableMetaInfo->tableMetaCapacity)) {
+  if (NULL == taosHashGetCloneExt(UTIL_GET_TABLEMETA(pSql), name, len, NULL, (void **)&(pTableMetaInfo->pTableMeta), &pTableMetaInfo->tableMetaCapacity)) {
     tfree(pTableMetaInfo->pTableMeta);
   }
   
@@ -2942,7 +2943,7 @@ int32_t tscGetTableMetaImpl(SSqlObj* pSql, STableMetaInfo *pTableMetaInfo, bool
   if (pMeta && pMeta->id.uid > 0) {
     // in case of child table, here only get the
     if (pMeta->tableType == TSDB_CHILD_TABLE) {
-      int32_t code = tscCreateTableMetaFromSTableMeta(&pTableMetaInfo->pTableMeta, name, &pTableMetaInfo->tableMetaCapacity, (STableMeta **)(&pSTMeta));
+      int32_t code = tscCreateTableMetaFromSTableMeta(pSql, &pTableMetaInfo->pTableMeta, name, &pTableMetaInfo->tableMetaCapacity, (STableMeta **)(&pSTMeta));
       pSql->pBuf   = (void *)(pSTMeta); 
       if (code != TSDB_CODE_SUCCESS) {
         return getTableMetaFromMnode(pSql, pTableMetaInfo, autocreate);
diff --git a/src/client/src/tscSql.c b/src/client/src/tscSql.c
index 5fdaad0d667c19548f699a9a8cfed7c9f017ad1b..2c8ef9b764a0aa2bbf8dd9304776175a8a599a27 100644
--- a/src/client/src/tscSql.c
+++ b/src/client/src/tscSql.c
@@ -194,6 +194,7 @@ TAOS *taos_connect_internal(const char *ip, const char *user, const char *pass,
     tscBuildAndSendRequest(pSql, NULL);
     tsem_wait(&pSql->rspSem);
 
+    pSql->pTscObj->pClusterInfo = (SClusterInfo *)tscAcquireClusterInfo(pSql->pTscObj->clusterId);
     if (pSql->res.code != TSDB_CODE_SUCCESS) {
       terrno = pSql->res.code;
       if (terrno ==TSDB_CODE_RPC_FQDN_ERROR) {
@@ -256,6 +257,7 @@ static void asyncConnCallback(void *param, TAOS_RES *tres, int code) {
   SSqlObj *pSql = (SSqlObj *) tres;
   assert(pSql != NULL);
   
+  pSql->pTscObj->pClusterInfo = (SClusterInfo *)tscAcquireClusterInfo(pSql->pTscObj->clusterId);
   pSql->fetchFp(pSql->param, tres, code);
 }
 
@@ -268,7 +270,6 @@ TAOS *taos_connect_a(char *ip, char *user, char *pass, char *db, uint16_t port,
   }
 
   if (taos) *taos = pObj;
-
   pSql->fetchFp = fp;
   pSql->res.code = tscBuildAndSendRequest(pSql, NULL);
   tscDebug("%p DB async connection is opening", taos);
diff --git a/src/client/src/tscSubquery.c b/src/client/src/tscSubquery.c
index 99a2a79dc60c89530eb9c2c7f6b5645ca0133ba1..58fb6c979b6d46cd71727b87c2e887d20abcdc15 100644
--- a/src/client/src/tscSubquery.c
+++ b/src/client/src/tscSubquery.c
@@ -3213,7 +3213,7 @@ static void multiVnodeInsertFinalize(void* param, TAOS_RES* tres, int numOfRows)
     for(int32_t i = 0; i < pParentObj->cmd.insertParam.numOfTables; ++i) {
       char name[TSDB_TABLE_FNAME_LEN] = {0};
       tNameExtractFullName(pParentObj->cmd.insertParam.pTableNameList[i], name);
-      taosHashRemove(tscTableMetaMap, name, strnlen(name, TSDB_TABLE_FNAME_LEN));
+      taosHashRemove(UTIL_GET_TABLEMETA(pParentObj), name, strnlen(name, TSDB_TABLE_FNAME_LEN));
     }
 
     pParentObj->res.code = TSDB_CODE_SUCCESS;
@@ -3358,7 +3358,7 @@ int32_t tscHandleMultivnodeInsert(SSqlObj *pSql) {
     goto _error;
   }
 
-  pCmd->insertParam.pDataBlocks = tscDestroyBlockArrayList(pCmd->insertParam.pDataBlocks);
+  pCmd->insertParam.pDataBlocks = tscDestroyBlockArrayList(pSql, pCmd->insertParam.pDataBlocks);
 
   // use the local variable
   for (int32_t j = 0; j < numOfSub; ++j) {
diff --git a/src/client/src/tscSystem.c b/src/client/src/tscSystem.c
index b3b83db80a70c19f79d1cd6a732d729817436dd3..edb8169f761e2b5aaba1ddfd7cda8a9008298948 100644
--- a/src/client/src/tscSystem.c
+++ b/src/client/src/tscSystem.c
@@ -33,9 +33,11 @@
 
 int32_t    sentinel = TSC_VAR_NOT_RELEASE;
 
-SHashObj  *tscVgroupMap;         // hash map to keep the vgroup info from mnode
-SHashObj  *tscTableMetaMap;      // table meta info buffer
-SCacheObj *tscVgroupListBuf;     // super table vgroup list information, only survives 5 seconds for each super table vgroup list
+//SHashObj  *tscVgroupMap;         // hash map to keep the vgroup info from mnode
+//SHashObj  *tscTableMetaMap;      // table meta info buffer
+//SCacheObj *tscVgroupListBuf;     // super table vgroup list information, only survives 5 seconds for each super table vgroup list
+SHashObj  *tscClusterMap = NULL;        // cluster obj
+static pthread_mutex_t clusterMutex; // mutex to protect open the cluster obj
 
 int32_t    tscObjRef = -1;
 void      *tscTmr;
@@ -121,6 +123,57 @@ int32_t tscAcquireRpc(const char *key, const char *user, const char *secretEncry
   return 0;
 }
 
+void tscClusterInfoDestroy(SClusterInfo *pObj) {
+  if (pObj == NULL) { return; }
+  taosHashCleanup(pObj->vgroupMap);
+  taosHashCleanup(pObj->tableMetaMap);
+  taosCacheCleanup(pObj->vgroupListBuf);
+  tfree(pObj);
+}
+
+void *tscAcquireClusterInfo(const char *clusterId) {
+  pthread_mutex_lock(&clusterMutex);
+  
+  size_t len = strlen(clusterId);
+  SClusterInfo *pObj   = NULL;
+  SClusterInfo **ppObj = taosHashGet(tscClusterMap, clusterId, len); 
+  if (ppObj == NULL || *ppObj == NULL) {
+    pObj = calloc(1, sizeof(SClusterInfo));
+    if (pObj) {
+      pObj->vgroupMap     = taosHashInit(256, taosGetDefaultHashFunction(TSDB_DATA_TYPE_INT), true, HASH_ENTRY_LOCK);
+      pObj->tableMetaMap  = taosHashInit(1024, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BINARY), true, HASH_ENTRY_LOCK); //
+      pObj->vgroupListBuf = taosCacheInit(TSDB_DATA_TYPE_BINARY, 5, false, NULL, "stable-vgroup-list");
+      if (pObj->vgroupMap == NULL || pObj->tableMetaMap == NULL || pObj->vgroupListBuf == NULL) {
+        tscClusterInfoDestroy(pObj);
+        pObj = NULL;
+      } else {
+        taosHashPut(tscClusterMap, clusterId, len, &pObj, POINTER_BYTES);
+      } 
+    }
+  } else {
+    pObj = *ppObj;
+  }
+
+  if (pObj) { pObj->ref += 1; }
+  
+  pthread_mutex_unlock(&clusterMutex);
+  return pObj;
+}
+void tscReleaseClusterInfo(const char *clusterId) {
+  pthread_mutex_lock(&clusterMutex);
+
+  size_t len = strlen(clusterId); 
+  SClusterInfo *pObj = NULL;
+  SClusterInfo **ppObj = taosHashGet(tscClusterMap, clusterId, len); 
+  if (ppObj != NULL && *ppObj != NULL) {
+    pObj = *ppObj;
+  }
+  if (pObj && --pObj->ref == 0) {
+    taosHashRemove(tscClusterMap, clusterId, len);
+    tscClusterInfoDestroy(pObj); 
+  }
+  pthread_mutex_unlock(&clusterMutex);
+}
 void taos_init_imp(void) {
   char temp[128] = {0};
 
@@ -188,12 +241,16 @@ void taos_init_imp(void) {
     taosTmrReset(tscCheckDiskUsage, 20 * 1000, NULL, tscTmr, &tscCheckDiskUsageTmr);      
   }
 
-  if (tscTableMetaMap == NULL) {
+  if (tscClusterMap == NULL) {
     tscObjRef        = taosOpenRef(40960, tscFreeRegisteredSqlObj);
-    tscVgroupMap     = taosHashInit(256, taosGetDefaultHashFunction(TSDB_DATA_TYPE_INT), true, HASH_ENTRY_LOCK);
-    tscTableMetaMap  = taosHashInit(1024, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BINARY), true, HASH_ENTRY_LOCK);
-    tscVgroupListBuf = taosCacheInit(TSDB_DATA_TYPE_BINARY, 5, false, NULL, "stable-vgroup-list");
-    tscDebug("TableMeta:%p, vgroup:%p is initialized", tscTableMetaMap, tscVgroupMap);
+
+    tscClusterMap    = taosHashInit(32, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BINARY), true, HASH_ENTRY_LOCK); 
+    pthread_mutex_init(&clusterMutex, NULL); 
+    //tscVgroupMap     = taosHashInit(256, taosGetDefaultHashFunction(TSDB_DATA_TYPE_INT), true, HASH_ENTRY_LOCK);
+    //tscTableMetaMap  = taosHashInit(1024, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BINARY), true, HASH_ENTRY_LOCK);
+    //tscVgroupListBuf = taosCacheInit(TSDB_DATA_TYPE_BINARY, 5, false, NULL, "stable-vgroup-list");
+    //tscDebug("TableMeta:%p, vgroup:%p is initialized", tscTableMetaMap, tscVgroupMap);
+
   }
    
   int refreshTime = 5;
@@ -222,12 +279,6 @@ void taos_cleanup(void) {
     scriptEnvPoolCleanup();
   }
 
-  taosHashCleanup(tscTableMetaMap);
-  tscTableMetaMap = NULL;
-
-  taosHashCleanup(tscVgroupMap);
-  tscVgroupMap = NULL;
-
   int32_t id = tscObjRef;
   tscObjRef = -1;
   taosCloseRef(id);
@@ -251,14 +302,16 @@ void taos_cleanup(void) {
   }
 
   pthread_mutex_destroy(&setConfMutex);
-  taosCacheCleanup(tscVgroupListBuf);
-  tscVgroupListBuf = NULL;
 
   if (tscEmbedded == 0) {
     rpcCleanup();
     taosCloseLog();
   };
 
+  taosHashCleanup(tscClusterMap);
+  tscClusterMap = NULL;
+  pthread_mutex_destroy(&clusterMutex);
+
   p = tscTmr;
   tscTmr = NULL;
   taosTmrCleanUp(p);
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index 04d1472bb0101e903aa697ccc443d60e386c4ba2..de588a953b5b38b94de7617e81eeef3bdb96037f 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -1421,6 +1421,7 @@ void destroyTableNameList(SInsertStatementParam* pInsertParam) {
 }
 
 void tscResetSqlCmd(SSqlCmd* pCmd, bool clearCachedMeta, uint64_t id) {
+  SSqlObj *pSql = (SSqlObj*)taosAcquireRef(tscObjRef, id);
   pCmd->command   = 0;
   pCmd->numOfCols = 0;
   pCmd->count     = 0;
@@ -1429,13 +1430,14 @@ void tscResetSqlCmd(SSqlCmd* pCmd, bool clearCachedMeta, uint64_t id) {
   pCmd->insertParam.sql = NULL;
   destroyTableNameList(&pCmd->insertParam);
 
-  pCmd->insertParam.pTableBlockHashList = tscDestroyBlockHashTable(pCmd->insertParam.pTableBlockHashList, clearCachedMeta);
-  pCmd->insertParam.pDataBlocks = tscDestroyBlockArrayList(pCmd->insertParam.pDataBlocks);
+  pCmd->insertParam.pTableBlockHashList = tscDestroyBlockHashTable(pSql, pCmd->insertParam.pTableBlockHashList, clearCachedMeta);
+  pCmd->insertParam.pDataBlocks = tscDestroyBlockArrayList(pSql, pCmd->insertParam.pDataBlocks);
   tfree(pCmd->insertParam.tagData.data);
   pCmd->insertParam.tagData.dataLen = 0;
 
   tscFreeQueryInfo(pCmd, clearCachedMeta, id);
   pCmd->pTableMetaMap = tscCleanupTableMetaMap(pCmd->pTableMetaMap);
+  taosReleaseRef(tscObjRef, id); 
 }
 
 void* tscCleanupTableMetaMap(SHashObj* pTableMetaMap) {
@@ -1571,7 +1573,7 @@ void tscDestroyBoundColumnInfo(SParsedDataColInfo* pColInfo) {
   tfree(pColInfo->colIdxInfo);
 }
 
-void tscDestroyDataBlock(STableDataBlocks* pDataBlock, bool removeMeta) {
+void tscDestroyDataBlock(SSqlObj *pSql, STableDataBlocks* pDataBlock, bool removeMeta) {
   if (pDataBlock == NULL) {
     return;
   }
@@ -1582,7 +1584,7 @@ void tscDestroyDataBlock(STableDataBlocks* pDataBlock, bool removeMeta) {
     char name[TSDB_TABLE_FNAME_LEN] = {0};
     tNameExtractFullName(&pDataBlock->tableName, name);
 
-    taosHashRemove(tscTableMetaMap, name, strnlen(name, TSDB_TABLE_FNAME_LEN));
+    taosHashRemove(UTIL_GET_TABLEMETA(pSql), name, strnlen(name, TSDB_TABLE_FNAME_LEN));
   }
 
   if (!pDataBlock->cloned) {
@@ -1623,7 +1625,7 @@ SParamInfo* tscAddParamToDataBlock(STableDataBlocks* pDataBlock, char type, uint
   return param;
 }
 
-void*  tscDestroyBlockArrayList(SArray* pDataBlockList) {
+void*  tscDestroyBlockArrayList(SSqlObj *pSql, SArray* pDataBlockList) {
   if (pDataBlockList == NULL) {
     return NULL;
   }
@@ -1631,7 +1633,7 @@ void*  tscDestroyBlockArrayList(SArray* pDataBlockList) {
   size_t size = taosArrayGetSize(pDataBlockList);
   for (int32_t i = 0; i < size; i++) {
     void* d = taosArrayGetP(pDataBlockList, i);
-    tscDestroyDataBlock(d, false);
+    tscDestroyDataBlock(pSql, d, false);
   }
 
   taosArrayDestroy(pDataBlockList);
@@ -1679,14 +1681,14 @@ void*  tscDestroyUdfArrayList(SArray* pUdfList) {
 
 
 
-void* tscDestroyBlockHashTable(SHashObj* pBlockHashTable, bool removeMeta) {
+void* tscDestroyBlockHashTable(SSqlObj *pSql, SHashObj* pBlockHashTable, bool removeMeta) {
   if (pBlockHashTable == NULL) {
     return NULL;
   }
 
   STableDataBlocks** p = taosHashIterate(pBlockHashTable, NULL);
   while(p) {
-    tscDestroyDataBlock(*p, removeMeta);
+    tscDestroyDataBlock(pSql, *p, removeMeta);
     p = taosHashIterate(pBlockHashTable, p);
   }
 
@@ -1927,7 +1929,7 @@ static int32_t getRowExpandSize(STableMeta* pTableMeta) {
   return result;
 }
 
-static void extractTableNameList(SInsertStatementParam *pInsertParam, bool freeBlockMap) {
+static void extractTableNameList(SSqlObj *pSql, SInsertStatementParam *pInsertParam, bool freeBlockMap) {
   pInsertParam->numOfTables = (int32_t) taosHashGetSize(pInsertParam->pTableBlockHashList);
   if (pInsertParam->pTableNameList == NULL) {
     pInsertParam->pTableNameList = malloc(pInsertParam->numOfTables * POINTER_BYTES);
@@ -1944,11 +1946,11 @@ static void extractTableNameList(SInsertStatementParam *pInsertParam, bool freeB
   }
 
   if (freeBlockMap) {
-    pInsertParam->pTableBlockHashList = tscDestroyBlockHashTable(pInsertParam->pTableBlockHashList, false);
+    pInsertParam->pTableBlockHashList = tscDestroyBlockHashTable(pSql, pInsertParam->pTableBlockHashList, false);
   }
 }
 
-int32_t tscMergeTableDataBlocks(SInsertStatementParam *pInsertParam, bool freeBlockMap) {
+int32_t tscMergeTableDataBlocks(SSqlObj *pSql, SInsertStatementParam *pInsertParam, bool freeBlockMap) {
   const int INSERT_HEAD_SIZE = sizeof(SMsgDesc) + sizeof(SSubmitMsg);
   int       code = 0;
   bool      isRawPayload = IS_RAW_PAYLOAD(pInsertParam->payloadType);
@@ -1973,7 +1975,7 @@ int32_t tscMergeTableDataBlocks(SInsertStatementParam *pInsertParam, bool freeBl
       if (ret != TSDB_CODE_SUCCESS) {
         tscError("0x%"PRIx64" failed to prepare the data block buffer for merging table data, code:%d", pInsertParam->objectId, ret);
         taosHashCleanup(pVnodeDataBlockHashList);
-        tscDestroyBlockArrayList(pVnodeDataBlockList);
+        tscDestroyBlockArrayList(pSql, pVnodeDataBlockList);
         tfree(blkKeyInfo.pKeyTuple);
         return ret;
       }
@@ -1992,7 +1994,7 @@ int32_t tscMergeTableDataBlocks(SInsertStatementParam *pInsertParam, bool freeBl
           tscError("0x%"PRIx64" failed to allocate memory for merging submit block, size:%d", pInsertParam->objectId, dataBuf->nAllocSize);
 
           taosHashCleanup(pVnodeDataBlockHashList);
-          tscDestroyBlockArrayList(pVnodeDataBlockList);
+          tscDestroyBlockArrayList(pSql, pVnodeDataBlockList);
           tfree(dataBuf->pData);
           tfree(blkKeyInfo.pKeyTuple);
 
@@ -2010,7 +2012,7 @@ int32_t tscMergeTableDataBlocks(SInsertStatementParam *pInsertParam, bool freeBl
       } else {
         if ((code = tscSortRemoveDataBlockDupRows(pOneTableBlock, &blkKeyInfo)) != 0) {
           taosHashCleanup(pVnodeDataBlockHashList);
-          tscDestroyBlockArrayList(pVnodeDataBlockList);
+          tscDestroyBlockArrayList(pSql, pVnodeDataBlockList);
           tfree(dataBuf->pData);
           tfree(blkKeyInfo.pKeyTuple);
           return code;
@@ -2057,7 +2059,7 @@ int32_t tscMergeTableDataBlocks(SInsertStatementParam *pInsertParam, bool freeBl
     pOneTableBlock = *p;
   }
 
-  extractTableNameList(pInsertParam, freeBlockMap);
+  extractTableNameList(pSql, pInsertParam, freeBlockMap);
 
   // free the table data blocks;
   pInsertParam->pDataBlocks = pVnodeDataBlockList;
@@ -2077,6 +2079,7 @@ void tscCloseTscObj(void *param) {
   tfree(pObj->tscCorMgmtEpSet);
   tscReleaseRpc(pObj->pRpcObj);
   pthread_mutex_destroy(&pObj->mutex);
+  tscReleaseClusterInfo(pObj->clusterId);
 
   tfree(pObj);
 }
@@ -4550,7 +4553,7 @@ CChildTableMeta* tscCreateChildMeta(STableMeta* pTableMeta) {
   return cMeta;
 }
 
-int32_t tscCreateTableMetaFromSTableMeta(STableMeta** ppChild, const char* name, size_t *tableMetaCapacity, STableMeta**ppSTable) {
+int32_t tscCreateTableMetaFromSTableMeta(SSqlObj *pSql, STableMeta** ppChild, const char* name, size_t *tableMetaCapacity, STableMeta**ppSTable) {
   assert(*ppChild != NULL);
   STableMeta* p      = *ppSTable;
   STableMeta* pChild = *ppChild;
@@ -4560,11 +4563,10 @@ int32_t tscCreateTableMetaFromSTableMeta(STableMeta** ppChild, const char* name,
     memset((char *)p, 0, sz);
   }
 
-  if (NULL == taosHashGetCloneExt(tscTableMetaMap, pChild->sTableName, strnlen(pChild->sTableName, TSDB_TABLE_FNAME_LEN), NULL, (void **)&p, &sz)) {
+  if (NULL == taosHashGetCloneExt(UTIL_GET_TABLEMETA(pSql), pChild->sTableName, strnlen(pChild->sTableName, TSDB_TABLE_FNAME_LEN), NULL, (void **)&p, &sz)) {
     tfree(p);
-  } else {
-    *ppSTable = p;
-  }
+  }   
+  *ppSTable = p;
 
   // tableMeta exists, build child table meta according to the super table meta
   // the uid need to be checked in addition to the general name of the super table.
@@ -4586,7 +4588,7 @@ int32_t tscCreateTableMetaFromSTableMeta(STableMeta** ppChild, const char* name,
     *ppChild = pChild;
     return TSDB_CODE_SUCCESS;
   } else { // super table has been removed, current tableMeta is also expired. remove it here
-    taosHashRemove(tscTableMetaMap, name, strnlen(name, TSDB_TABLE_FNAME_LEN));
+    taosHashRemove(UTIL_GET_TABLEMETA(pSql), name, strnlen(name, TSDB_TABLE_FNAME_LEN));
     return -1;
   }
 }
@@ -5105,18 +5107,20 @@ SNewVgroupInfo createNewVgroupInfo(SVgroupMsg *pVgroupMsg) {
 
 void tscRemoveCachedTableMeta(STableMetaInfo* pTableMetaInfo, uint64_t id) {
   char fname[TSDB_TABLE_FNAME_LEN] = {0};
-  tNameExtractFullName(&pTableMetaInfo->name, fname);
+  SSqlObj *p = (SSqlObj *)taosAcquireRef(tscObjRef, id); 
 
+  tNameExtractFullName(&pTableMetaInfo->name, fname);
   int32_t len = (int32_t) strnlen(fname, TSDB_TABLE_FNAME_LEN);
   if (UTIL_TABLE_IS_SUPER_TABLE(pTableMetaInfo)) {
-    void* pv = taosCacheAcquireByKey(tscVgroupListBuf, fname, len);
+    void* pv = taosCacheAcquireByKey(UTIL_GET_VGROUPLIST(p), fname, len);
     if (pv != NULL) {
-      taosCacheRelease(tscVgroupListBuf, &pv, true);
+      taosCacheRelease(UTIL_GET_VGROUPLIST(p), &pv, true);
     }
   }
 
-  taosHashRemove(tscTableMetaMap, fname, len);
-  tscDebug("0x%"PRIx64" remove table meta %s, numOfRemain:%d", id, fname, (int32_t) taosHashGetSize(tscTableMetaMap));
+  taosHashRemove(UTIL_GET_TABLEMETA(p), fname, len);
+  tscDebug("0x%"PRIx64" remove table meta %s, numOfRemain:%d", id, fname, (int32_t) taosHashGetSize(UTIL_GET_TABLEMETA(p)));
+  taosReleaseRef(tscObjRef, id); 
 }
 
 char* cloneCurrentDBName(SSqlObj* pSql) {
diff --git a/tests/examples/c/connect_two_cluster.c b/tests/examples/c/connect_two_cluster.c
new file mode 100644
index 0000000000000000000000000000000000000000..fa54dd437036f12915d62a60f96b90e6a7adc45f
--- /dev/null
+++ b/tests/examples/c/connect_two_cluster.c
@@ -0,0 +1,162 @@
+#include <stdio.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include "taos.h"
+int numOfThreads = 1;
+
+void* connectClusterAndDeal(void *arg) {
+  int port = *(int *)arg;
+  const char *host = "127.0.0.1";  
+  const char *user = "root";  
+  const char *passwd = "taosdata"; 
+  TAOS* taos1 = taos_connect(host, user, passwd, "", port); 
+  TAOS* taos2 = taos_connect(host, user, passwd, "", port + 1000); 
+  if (NULL == taos1 || NULL == taos2) {
+    printf("connect to (%d/%d) failed \n", port, port + 1000); 
+    return NULL;
+  } 
+  TAOS_RES *result = NULL;
+  result = taos_query(taos1, "drop database if exists db"); 
+  if (0 != taos_errno(result)) {
+    printf("failed %s\n", taos_errstr(result));
+  }
+  taos_free_result(result);
+
+  taos_query(taos2, "drop database if exists db"); 
+  if (0 != taos_errno(result)) {
+    printf("failed %s\n", taos_errstr(result));
+  }
+  
+  taos_free_result(result);
+  // ========= build database
+  {
+    result = taos_query(taos1, "create database db");
+    if (0 != taos_errno(result)) {
+      printf("failed %s\n", taos_errstr(result));
+    }
+    
+    taos_free_result(result);
+  }
+  {
+    result = taos_query(taos2, "create database db");
+    if (0 != taos_errno(result)) {
+      printf("failed %s\n", taos_errstr(result));
+    }
+    taos_free_result(result);
+  }
+  
+  //======== create table 
+  {
+    result = taos_query(taos1, "create stable db.stest (ts timestamp, port int) tags(tport int)");
+    if (0 != taos_errno(result)) {
+      printf("failed %s\n", taos_errstr(result));
+    }
+    taos_free_result(result);
+  }
+  {
+    result = taos_query(taos2, "create stable db.stest (ts timestamp, port int) tags(tport int)");
+    if (0 != taos_errno(result)) {
+      printf("failed %s\n", taos_errstr(result));
+    }
+    taos_free_result(result);
+
+  }
+  //======== create table 
+  {
+    result = taos_query(taos1, "use db");
+    if (0 != taos_errno(result)) {
+      printf("failed %s\n", taos_errstr(result));
+    }
+    taos_free_result(result);
+  }
+  {
+    result = taos_query(taos2, "use db");
+    if (0 != taos_errno(result)) {
+      printf("failed %s\n", taos_errstr(result));
+    }
+    taos_free_result(result);
+
+  }
+  {
+    char buf[1024] = {0};
+    sprintf(buf, "insert into db.t1 using stest tags(%d) values(now, %d)", port, port);
+    for (int i = 0; i < 100000; i++) {
+      //printf("error here\t");
+      result = taos_query(taos1, buf);
+    if (0 != taos_errno(result)) {
+      printf("failed %s\n", taos_errstr(result));
+    }
+      taos_free_result(result);
+      //sleep(1); 
+    }
+  }
+
+  {
+    char buf[1024] = {0};
+    sprintf(buf, "insert into db.t1 using stest tags(%d) values(now, %d)", port + 1000, port + 1000);
+    for (int i = 0; i < 100000; i++) {
+      result = taos_query(taos2, buf);
+      if (0 != taos_errno(result)) {
+        printf("failed %s\n", taos_errstr(result));
+      }
+      taos_free_result(result);
+      //sleep(1); 
+    }
+  }
+  // query result
+  {
+    result = taos_query(taos1, "select * from stest");
+    if (result == NULL || taos_errno(result) != 0) {
+      printf("query failed %s\n", taos_errstr(result));
+      taos_free_result(result);
+    }
+    TAOS_ROW row;
+    int rows = 0;
+    int num_fields = taos_field_count(result);
+    TAOS_FIELD *fields = taos_fetch_fields(result);
+    while ((row = taos_fetch_row(result))) {
+      char temp[1024] = {0};
+      rows++;
+      taos_print_row(temp, row, fields , num_fields);
+      printf("%s\n", temp);
+    }
+    taos_free_result(result);
+  } 
+
+  // query result
+  {
+    result = taos_query(taos2, "select * from stest");
+    if (result == NULL || taos_errno(result) != 0) {
+      printf("query failed %s\n", taos_errstr(result));
+      taos_free_result(result);
+    }
+    TAOS_ROW row;
+    int rows = 0;
+    int num_fields = taos_field_count(result);
+    TAOS_FIELD *fields = taos_fetch_fields(result);
+    while ((row = taos_fetch_row(result))) {
+      char temp[1024] = {0};
+      rows++;
+      taos_print_row(temp, row, fields , num_fields);
+      printf("%s\n", temp);
+    }
+    taos_free_result(result);
+  } 
+  taos_close(taos1); 
+  taos_close(taos2); 
+  return NULL;
+}
+int main(int argc, char* argv[]) {
+  pthread_t *pthreads = malloc(sizeof(pthread_t) * numOfThreads);   
+  
+  int *port = malloc(sizeof(int) * numOfThreads);
+  port[0] = 6030;
+  for (int i = 0; i < numOfThreads; i++) {
+    pthread_create(&pthreads[i], NULL, connectClusterAndDeal, (void *)&port[i]);
+  }
+  for (int i = 0; i < numOfThreads; i++) {
+    pthread_join(pthreads[i], NULL);
+  }
+  free(port);
+}
diff --git a/tests/pytest/client/one_client_connect_two_server.py b/tests/pytest/client/one_client_connect_two_server.py
new file mode 100644
index 0000000000000000000000000000000000000000..4d5b127405ffbdaa533a9f628b4bb2323b168d71
--- /dev/null
+++ b/tests/pytest/client/one_client_connect_two_server.py
@@ -0,0 +1,342 @@
+###################################################################
+#           Copyright (c) 2016 by TAOS Technologies, Inc.
+#                     All rights reserved.
+#
+#  This file is proprietary and confidential to TAOS Technologies.
+#  No part of this file may be reproduced, stored, transmitted,
+#  disclosed or used in any form or by any means other than as
+#  expressly provided by the written permission from Jianhui Tao
+#
+###################################################################
+
+# -*- coding: utf-8 -*-
+
+import sys
+import json
+import taos
+import time
+import random
+
+from util.log import *
+from util.cases import *
+from util.sql import *
+from util.dnodes import *
+
+
+'''
+
+Before test start，Two TDengine services have been set up on different servers 
+
+'''
+
+host1 = '192.168.1.101'
+host2 = '192.168.1.102'
+user = 'root'
+password = 'taosdata'
+cfgdir = '/home/cp/taos/TDengine/sim/dnode1/cfg'
+
+conn1 = taos.connect(host=host1, user=user, password=password, config=cfgdir)
+conn2 = taos.connect(host=host2, user=user, password=password, config=cfgdir)
+cursor1 = conn1.cursor()
+cursor2 = conn2.cursor()
+tdSql1 = TDSql()
+tdSql2 = TDSql()
+tdSql1.init(cursor1)
+tdSql2.init(cursor2)
+
+dbname11 = 'db11'
+dbname12 = 'db12'
+dbname21 = 'db21'
+stbname11 = 'stb11'
+stbname12 = 'stb12'
+stbname21 = 'stb21'
+tbnum = 100
+data_row = 100
+db1_stb1_column = 'ts timestamp, c1 int, c2 float, c3 timestamp, c4 binary(16), c5 double, c6 bool, c7 bigint, c8 smallint, c9 tinyint, c10 nchar(16)  '
+db1_stb1_tag = 'st1 int, st2 float, st3 timestamp, st4 binary(16), st5 double, st6 bool, st7 bigint, st8 smallint, st9 tinyint, st10 nchar(16)'
+
+def dbsql(dbname):
+    return f"create database {dbname} keep 3650"
+
+def stbsql(stbname, columntype, tagtype):
+    return f'create stable {stbname} ({columntype}) tags ({tagtype}) '
+
+def tbsql(tbname, stbname, tags):
+    return f'create table {tbname} using {stbname} tags ({tags})'
+
+def datasql(tbname, data):
+    return f'insert into {tbname} values ({data})'
+
+def testquery():
+    ti = random.randint(0,tbnum-1)
+
+    tdSql1.query(f"select c1, c2, c3, c4, c5, c6, c7, c8, c9, c10 from tm{ti}")
+    tdSql1.checkData(0, 0, ti)
+    tdSql1.checkData(0, 1, ti)
+    tdSql1.checkData(0, 2, ti)
+    tdSql1.checkData(0, 3, f'binary_{ti}')
+    tdSql1.checkData(0, 4, ti)
+    tdSql1.checkData(0, 5, ti%2)
+    tdSql1.checkData(0, 6, ti)
+    tdSql1.checkData(0, 7, ti%32768)
+    tdSql1.checkData(0, 8, ti%128)
+    tdSql1.checkData(0, 9, f'nchar_{ti}')
+    tdSql2.query(f"select c1, c2, c3, c4, c5, c6, c7, c8, c9, c10 from tn{ti}")
+    tdSql2.checkData(0, 0, ti+10000)
+    tdSql2.checkData(0, 1, ti+10000)
+    tdSql2.checkData(0, 2, ti+10000)
+    tdSql2.checkData(0, 3, f'binary_{ti+10000}')
+    tdSql2.checkData(0, 4, ti+10000)
+    tdSql2.checkData(0, 5, (ti+10000)%2)
+    tdSql2.checkData(0, 6, ti+10000)
+    tdSql2.checkData(0, 7, (ti+10000)%32768)
+    tdSql2.checkData(0, 8, (ti+10000)%128)
+    tdSql2.checkData(0, 9, f'nchar_{ti+10000}')
+
+    tdSql1.query(f"select last(c1, c2, c3, c4, c5, c6, c7, c8, c9, c10) from {stbname11}")
+    tdSql1.checkData(0, 0, data_row-1)
+    tdSql1.checkData(0, 1, data_row-1)
+    tdSql1.checkData(0, 2, data_row-1)
+    tdSql1.checkData(0, 3, f'binary_{data_row-1}')
+    tdSql1.checkData(0, 4, data_row-1)
+    tdSql1.checkData(0, 5, (data_row-1)%2)
+    tdSql1.checkData(0, 6, data_row-1)
+    tdSql1.checkData(0, 7, (data_row-1)%32768)
+    tdSql1.checkData(0, 8, (data_row-1)%128)
+    tdSql1.checkData(0, 9, f'nchar_{data_row-1}')
+
+    tdSql1.query(f"select first(c1, c2, c3, c4, c5, c6, c7, c8, c9, c10) from {stbname11}")
+    tdSql1.checkData(0, 0, 0)
+    tdSql1.checkData(0, 1, 0)
+    tdSql1.checkData(0, 2, 0)
+    tdSql1.checkData(0, 3, f'binary_0')
+    tdSql1.checkData(0, 4, 0)
+    tdSql1.checkData(0, 5, 0)
+    tdSql1.checkData(0, 6, 0)
+    tdSql1.checkData(0, 7, 0)
+    tdSql1.checkData(0, 8, 0)
+    tdSql1.checkData(0, 9, f'nchar_0')
+
+    tdSql1.error("select * from")
+
+    tdSql1.query(f"select last(*) from tm1")
+    tdSql1.checkData(0, 1, 1)
+    tdSql1.checkData(0, 4, "binary_1")
+
+
+    tdSql1.query(f"select min(c1),max(c2) from {stbname11}")
+    tdSql1.checkData(0, 0, 0)
+    tdSql1.checkData(0, 1, data_row-1)
+
+    tdSql2.query(f"select count(*), count(c1) from {stbname21}")
+    tdSql2.checkData(0, 0, data_row)
+    tdSql2.checkData(0, 1, data_row)
+
+    tdSql2.query(f"select first(c1, c2, c3, c4, c5, c6, c7, c8, c9, c10) from {stbname21}")
+    tdSql2.checkData(0, 0, 10000)
+    tdSql2.checkData(0, 1, 10000)
+    tdSql2.checkData(0, 2, 10000)
+    tdSql2.checkData(0, 3, f'binary_10000')
+    tdSql2.checkData(0, 4, 10000)
+    tdSql2.checkData(0, 5, 10000%2)
+    tdSql2.checkData(0, 6, 10000)
+    tdSql2.checkData(0, 7, 10000%32768)
+    tdSql2.checkData(0, 8, 10000%128)
+    tdSql2.checkData(0, 9, f'nchar_10000')
+
+    tdSql2.query(f"select last(c1, c2, c3, c4, c5, c6, c7, c8, c9, c10) from {stbname21}")
+    tdSql2.checkData(0, 0, data_row+9999)
+    tdSql2.checkData(0, 1, data_row+9999)
+    tdSql2.checkData(0, 2, data_row+9999)
+    tdSql2.checkData(0, 3, f'binary_{data_row+9999}')
+    tdSql2.checkData(0, 4, data_row+9999)
+    tdSql2.checkData(0, 5, (data_row+9999)%2)
+    tdSql2.checkData(0, 6, data_row+9999)
+    tdSql2.checkData(0, 7, (data_row+9999)%32768)
+    tdSql2.checkData(0, 8, (data_row+9999)%128)
+    tdSql2.checkData(0, 9, f'nchar_{data_row+9999}')
+
+    tdSql1.query(f"select max(c1) from (select top(c1,10) c1 from {stbname11})")
+    tdSql1.checkData(0, 0, data_row-1)
+    tdSql2.query(f"select max(c1) from (select top(c1,10) c1 from {stbname21})")
+    tdSql2.checkData(0, 0, data_row+9999)
+
+    tdSql1.query(f"select avg(c1) from {stbname11}")
+    tdSql1.checkData(0, 0, sum(range(data_row))/data_row)
+    tdSql2.query(f"select avg(c1) from {stbname21}")
+    tdSql2.checkData(0, 0, sum(range(data_row))/data_row+10000)
+
+    tdSql1.query(f"select spread(c1) from {stbname11}")
+    tdSql1.checkData(0, 0, data_row-1)
+    tdSql2.query(f"select spread(c1) from {stbname21}")
+    tdSql2.checkData(0, 0, data_row-1)
+
+    tdSql1.query(f"select max(c1)*2 from {stbname11}")
+    tdSql1.checkData(0, 0, (data_row-1)*2)
+    tdSql2.query(f"select max(c1)*2 from {stbname21}")
+    tdSql2.checkData(0, 0, (data_row+9999)*2)
+
+    tdSql1.query(f"select avg(c1) from {stbname11} where c1 <= 10")
+    tdSql1.checkData(0, 0, 5)
+    tdSql2.query(f"select avg(c1) from {stbname21} where c1 <= 10010")
+    tdSql2.checkData(0, 0, 10005)
+
+    tdSql1.query(f"select * from {stbname11} where tbname like 'tn%'")
+    tdSql1.checkRows(0)
+    tdSql2.query(f"select * from {stbname21} where tbname like 'tm%'")
+    tdSql2.checkRows(0)
+
+    tdSql1.query(f"select max(c1) from {stbname11} group by tbname")
+    tdSql1.checkRows(tbnum)
+    tdSql2.query(f"select max(c1) from {stbname21} group by tbname")
+    tdSql2.checkRows(tbnum)
+
+    tdSql1.error(f"select * from {stbname11}, {stbname21} where {stbname11}.ts = {stbname21}.ts and {stbname11}.st1 = {stbname21}.st1")
+    tdSql2.error(f"select * from {stbname11}, {stbname21} where {stbname11}.ts = {stbname21}.ts and {stbname11}.st1 = {stbname21}.st1")
+
+if __name__ == '__main__':
+
+    tdSql1.execute('reset query cache')
+    tdSql2.execute('reset query cache')
+    tdSql1.execute(f'drop database if exists {dbname11}')
+    tdSql1.execute(f'drop database if exists {dbname12}')
+    tdSql1.execute(f'drop database if exists {dbname21}')
+    tdSql2.execute(f'drop database if exists {dbname21}')
+    tdSql2.execute(f'drop database if exists {dbname11}')
+    tdSql2.execute(f'drop database if exists {dbname12}')
+
+    tdSql1.execute(dbsql(dbname11))
+    tdSql1.query('show databases')
+    tdSql1.checkRows(1)
+    tdSql2.query('show databases')
+    tdSql2.checkRows(0)
+
+    tdSql2.execute(dbsql(dbname21))
+
+    tdSql1.query(f'show databases')
+    tdSql1.checkData(0, 0, dbname11)
+    tdSql2.query(f'show databases')
+    tdSql2.checkData(0, 0, dbname21)
+
+    tdSql1.execute(f'use {dbname11}')
+    tdSql1.query("show stables")
+    tdSql1.checkRows(0)
+    tdSql2.error("show stables")
+
+
+    ### conn1 create stable
+    tdSql1.execute(stbsql(stbname11, db1_stb1_column, db1_stb1_tag))
+    tdSql1.query(f"show stables like '{stbname11}' ")
+    tdSql1.checkRows(1)
+    tdSql2.error("show stables")
+
+    # 'st1 int, st2 float, st3 timestamp, st4 binary(16), st5 double, st6 bool, st7 bigint, st8 smallint, st9 tinyint, st10 nchar(16)'
+    for i in range(100):
+        t1name = f"t{i}"
+        stname = stbname11
+        tags = f'{i}, {i}, {i}, "binary_{i}", {i}, {i%2}, {i}, {i%32768}, {i%128}, "nchar_{i}"'
+        tdSql1.execute(tbsql(t1name, stname, tags))
+
+    tdSql2.error(f'select * from t{random.randint(0, 99)}')
+
+    tdSql1.query("show tables")
+    tdSql1.checkRows(100)
+    tdSql2.error("show tables")
+
+    tdSql1.query(f'select * from {stbname11}')
+    # tdSql1.query(f'select * from t1')
+    tdSql1.checkRows(0)
+    tdSql2.error(f'select * from {stname}')
+
+    # conn1 insert data
+    # 'ts timestamp, c1 int, c2 float, c3 timestamp, c4 binary(16), c5 double, c6 bool, c7 bigint, c8 smallint, c9 tinyint, c10 nchar(16)  '
+    nowtime = int(round(time.time() * 1000))
+    for i in range(100):
+        data = f'{nowtime+i*10}, {i}, {i}, {i}, "binary_{i}", {i}, {i%2}, {i}, {i%32768}, {i%128}, "nchar_{i}"'
+        tdSql1.execute(datasql(f"t{i}", data))
+        # tdSql2.error(datasql(f't{i}', data))
+    ti = random.randint(0,99)
+    tdSql1.query(f"select c1, c2, c3, c4, c5, c6, c7, c8, c9, c10 from t{ti}")
+    tdSql1.checkData(0, 0, ti)
+    tdSql1.checkData(0, 1, ti)
+    tdSql1.checkData(0, 2, ti)
+    tdSql1.checkData(0, 3, f'binary_{ti}')
+    tdSql1.checkData(0, 4, ti)
+    tdSql1.checkData(0, 5, ti%2)
+    tdSql1.checkData(0, 6, ti)
+    tdSql1.checkData(0, 7, ti%32768)
+    tdSql1.checkData(0, 8, ti%128)
+    tdSql1.checkData(0, 9, f'nchar_{ti}')
+    tdSql2.error(f"select c1, c2, c3, c4, c5, c6, c7, c8, c9, c10 from t{ti}")
+
+    # delete conn1.database and reinsert the data to conn1.db and conn2.db
+    tdSql1.execute(f"drop database if exists {dbname11}")
+    tdSql1.query("show databases")
+    tdSql1.checkRows(0)
+    tdSql2.query(f"show databases")
+    tdSql2.checkData(0, 0, dbname21)
+
+    tdSql1.execute(dbsql(dbname11))
+    tdSql1.query(f"show databases")
+    tdSql1.checkData(0, 0, dbname11)
+    tdSql2.query(f"show databases ")
+    tdSql2.checkData(0, 0, dbname21)
+
+    tdSql1.execute(dbsql(dbname12))
+    tdSql1.query("show databases")
+    tdSql1.checkData(0, 0, dbname11)
+    tdSql1.checkData(1, 0, dbname12)
+    tdSql2.query("show databases")
+    tdSql2.checkData(0, 0, dbname21)
+
+    tdSql1.execute(f"use {dbname11}")
+    tdSql1.query("show stables")
+    tdSql1.checkRows(0)
+    tdSql2.error("show stables")
+
+    tdSql2.execute(f"use {dbname21}")
+    tdSql2.query("show stables")
+    tdSql2.checkRows(0)
+    tdSql2.error(f"use {dbname12}")
+
+    tdSql1.execute(stbsql(stbname11, db1_stb1_column, db1_stb1_tag))
+    tdSql1.query("show stables")
+    tdSql1.checkRows(1)
+    tdSql2.query("show stables")
+    tdSql2.checkRows(0)
+
+    tdSql2.execute(stbsql(stbname21, db1_stb1_column, db1_stb1_tag))
+    tdSql1.query("show stables ")
+    tdSql1.checkRows(1)
+    tdSql1.query(f"show stables like '{stbname11}' ")
+    tdSql1.checkRows(1)
+    tdSql2.query("show stables ")
+    tdSql1.checkRows(1)
+    tdSql2.query(f"show stables like '{stbname21}' ")
+    tdSql1.checkRows(1)
+
+    for i in range(tbnum):
+        t1name = f"tm{i}"
+        t2name = f"tn{i}"
+        s1tname = stbname11
+        s2tname = stbname21
+        tags = f'{i}, {i}, {i}, "binary_{i}", {i}, {i % 2}, {i}, {i % 32768}, {i % 128}, "nchar_{i}"'
+        tdSql1.execute(tbsql(t1name, s1tname, tags))
+        # tdSql2.error(f'select * from {t1name}')
+        tdSql2.execute(tbsql(t2name, s2tname, tags))
+        # tdSql2.query(f'select * from {t2name}')
+        # tdSql1.error(f'select * from {t2name}')
+
+
+    tdSql1.query("show tables like 'tm%' ")
+    tdSql1.checkRows(tbnum)
+    tdSql2.query("show tables like 'tn%' ")
+    tdSql2.checkRows(tbnum)
+
+    for i in range(data_row):
+        data1 = f'{nowtime + i * 10}, {i}, {i}, {i}, "binary_{i}", {i}, {i % 2}, {i}, {i % 32768}, {i % 128}, "nchar_{i}"'
+        data2 = f'{nowtime+i*10}, {i+10000}, {i+10000}, {i+10000}, "binary_{i+10000}", {i+10000}, {(i+10000)%2}, {i+10000}, {(i+10000)%32768}, {(i+10000)%128}, "nchar_{i+10000}" '
+        tdSql1.execute(datasql(f"tm{i}", data1))
+        tdSql2.execute(datasql(f'tn{i}', data2))
+
+    testquery()
\ No newline at end of file