diff --git a/packaging/cfg/taos.cfg b/packaging/cfg/taos.cfg
index 9d61b0df68f3480834fddacd5d701ee0559352e8..fa289c277cf273396375690c8a496fd4eacd77fe 100644
--- a/packaging/cfg/taos.cfg
+++ b/packaging/cfg/taos.cfg
@@ -100,6 +100,9 @@
 # default system charset
 # charset               UTF-8
 
+# system time zone
+# timezone              Asia/Shanghai (CST, +0800)
+
 # enable/disable commit log
 # clog                  1
 
diff --git a/src/client/inc/tscUtil.h b/src/client/inc/tscUtil.h
index 6666fa24a605c186678b2642b9735432b75a8df4..da4ebc4e9cadbeda7755ad35d57889035ffcd0b2 100644
--- a/src/client/inc/tscUtil.h
+++ b/src/client/inc/tscUtil.h
@@ -107,14 +107,6 @@ void tscAddSpecialColumnForSelect(SSqlCmd* pCmd, int32_t outputColIndex, int16_t
 
 void addRequiredTagColumn(SSqlCmd* pCmd, int32_t tagColIndex, int32_t tableIndex);
 
-//TODO refactor, remove
-void SStringFree(SString* str);
-void SStringCopy(SString* pDest, const SString* pSrc);
-SString SStringCreate(const char* str);
-
-int32_t SStringAlloc(SString* pStr, int32_t size);
-int32_t SStringEnsureRemain(SString* pStr, int32_t size);
-
 int32_t setMeterID(SSqlObj* pSql, SSQLToken* pzTableName, int32_t tableIndex);
 void tscClearInterpInfo(SSqlCmd* pCmd);
 
@@ -226,7 +218,7 @@ void addGroupInfoForSubquery(SSqlObj* pParentObj, SSqlObj* pSql, int32_t tableIn
 
 void doAddGroupColumnForSubquery(SSqlCmd* pCmd, int32_t tagIndex);
 
-int16_t tscGetJoinTagColIndexByUid(SSqlCmd* pCmd, uint64_t uid);
+int16_t tscGetJoinTagColIndexByUid(STagCond* pTagCond, uint64_t uid);
 
 TAOS* taos_connect_a(char* ip, char* user, char* pass, char* db, uint16_t port, void (*fp)(void*, TAOS_RES*, int),
                      void* param, void** taos);
diff --git a/src/client/inc/tsclient.h b/src/client/inc/tsclient.h
index 6226cf1f1d836c8ba42d131b42c03a644ba0ce74..d439ba9929ac7c58eb08d946cc7289fd1d8dbee7 100644
--- a/src/client/inc/tsclient.h
+++ b/src/client/inc/tsclient.h
@@ -188,7 +188,7 @@ typedef struct SString {
 
 typedef struct SCond {
   uint64_t uid;
-  SString  cond;
+  char* cond;
 } SCond;
 
 typedef struct SJoinNode {
diff --git a/src/client/src/tscAsync.c b/src/client/src/tscAsync.c
index d11a279247ff170ba4b931b11a93589e3e2b3693..abf91e7c4339bdebe7c72f14551da0e1d53132c5 100644
--- a/src/client/src/tscAsync.c
+++ b/src/client/src/tscAsync.c
@@ -51,7 +51,7 @@ void taos_query_a(TAOS *taos, const char *sqlstr, void (*fp)(void *, TAOS_RES *,
   }
 
   int32_t sqlLen = strlen(sqlstr);
-  if (sqlLen > TSDB_MAX_SQL_LEN) {
+  if (sqlLen > tsMaxSQLStringLen) {
     tscError("sql string too long");
     tscQueueAsyncError(fp, param);
     return;
diff --git a/src/client/src/tscJoinProcess.c b/src/client/src/tscJoinProcess.c
index 17ea5cf8862f3fdb42f95cc80b84acf9394d26ae..ed44d540667284e6af66e184152d0b2fe0a27dc3 100644
--- a/src/client/src/tscJoinProcess.c
+++ b/src/client/src/tscJoinProcess.c
@@ -307,7 +307,7 @@ int32_t tscLaunchSecondSubquery(SSqlObj* pSql) {
       SSqlExpr* pExpr = tscSqlExprGet(&pNew->cmd, 0);
       assert(pNew->cmd.tagCond.joinInfo.hasJoin);
 
-      int16_t tagColIndex = tscGetJoinTagColIndexByUid(&pNew->cmd, pMeterMetaInfo->pMeterMeta->uid);
+      int16_t tagColIndex = tscGetJoinTagColIndexByUid(&pNew->cmd.tagCond, pMeterMetaInfo->pMeterMeta->uid);
       pExpr->param[0].i64Key = tagColIndex;
       pExpr->numOfParams = 1;
 
diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index ba465c28b963155ef83b9d9617267fe0c0b26beb..d0aa290d3183dd549f3065863037e6d80db0d4ae 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -21,6 +21,7 @@
 #include "taosmsg.h"
 #include "tstoken.h"
 #include "ttime.h"
+#include "tstrbuild.h"
 
 #include "tscUtil.h"
 #include "tschemautil.h"
@@ -3103,26 +3104,23 @@ static int32_t optrToString(tSQLExpr* pExpr, char** exprString) {
   return TSDB_CODE_SUCCESS;
 }
 
-static int32_t tablenameListToString(tSQLExpr* pExpr, char* str) {
+static int32_t tablenameListToString(tSQLExpr* pExpr, /*char* str*/SStringBuilder* sb) {
   tSQLExprList* pList = pExpr->pParam;
   if (pList->nExpr <= 0) {
     return TSDB_CODE_INVALID_SQL;
   }
 
   if (pList->nExpr > 0) {
-    strcpy(str, QUERY_COND_REL_PREFIX_IN);
-    str += QUERY_COND_REL_PREFIX_IN_LEN;
+    taosStringBuilderAppendStringLen(sb, QUERY_COND_REL_PREFIX_IN, QUERY_COND_REL_PREFIX_IN_LEN);
   }
 
   int32_t len = 0;
   for (int32_t i = 0; i < pList->nExpr; ++i) {
     tSQLExpr* pSub = pList->a[i].pNode;
-    strncpy(str + len, pSub->val.pz, pSub->val.nLen);
-
-    len += pSub->val.nLen;
+    taosStringBuilderAppendStringLen(sb, pSub->val.pz, pSub->val.nLen);
 
     if (i < pList->nExpr - 1) {
-      str[len++] = TBNAME_LIST_SEP[0];
+      taosStringBuilderAppendString(sb, TBNAME_LIST_SEP);
     }
 
     if (pSub->val.nLen <= 0 || pSub->val.nLen > TSDB_METER_NAME_LEN) {
@@ -3133,11 +3131,9 @@ static int32_t tablenameListToString(tSQLExpr* pExpr, char* str) {
   return TSDB_CODE_SUCCESS;
 }
 
-static int32_t tablenameCondToString(tSQLExpr* pExpr, char* str) {
-  strcpy(str, QUERY_COND_REL_PREFIX_LIKE);
-  str += strlen(QUERY_COND_REL_PREFIX_LIKE);
-
-  strcpy(str, pExpr->val.pz);
+static int32_t tablenameCondToString(tSQLExpr* pExpr, /*char* str*/SStringBuilder* sb) {
+  taosStringBuilderAppendStringLen(sb, QUERY_COND_REL_PREFIX_LIKE, QUERY_COND_REL_PREFIX_LIKE_LEN);
+  taosStringBuilderAppendString(sb, pExpr->val.pz);
 
   return TSDB_CODE_SUCCESS;
 }
@@ -3241,7 +3237,7 @@ static int32_t getTagCondString(SSqlCmd* pCmd, tSQLExpr* pExpr, char** str) {
   return tSQLExprLeafToString(pExpr, true, str);
 }
 
-static int32_t getTablenameCond(SSqlCmd* pCmd, tSQLExpr* pTableCond, char* str) {
+static int32_t getTablenameCond(SSqlCmd* pCmd, tSQLExpr* pTableCond, /*char* str*/SStringBuilder* sb) {
   const char* msg0 = "invalid table name list";
 
   if (pTableCond == NULL) {
@@ -3258,9 +3254,9 @@ static int32_t getTablenameCond(SSqlCmd* pCmd, tSQLExpr* pTableCond, char* str)
   int32_t ret = TSDB_CODE_SUCCESS;
 
   if (pTableCond->nSQLOptr == TK_IN) {
-    ret = tablenameListToString(pRight, str);
+    ret = tablenameListToString(pRight, sb);
   } else if (pTableCond->nSQLOptr == TK_LIKE) {
-    ret = tablenameCondToString(pRight, str);
+    ret = tablenameCondToString(pRight, sb);
   }
 
   if (ret != TSDB_CODE_SUCCESS) {
@@ -3828,8 +3824,7 @@ int tableNameCompar(const void* lhs, const void* rhs) {
   return ret > 0 ? 1 : -1;
 }
 
-static int32_t setTableCondForMetricQuery(SSqlObj* pSql, tSQLExpr* pExpr, int16_t tableCondIndex,
-                                          char* tmpTableCondBuf) {
+static int32_t setTableCondForMetricQuery(SSqlObj* pSql, tSQLExpr* pExpr, int16_t tableCondIndex, SStringBuilder* sb) {
   SSqlCmd*    pCmd = &pSql->cmd;
   const char* msg = "meter name too long";
 
@@ -3842,26 +3837,25 @@ static int32_t setTableCondForMetricQuery(SSqlObj* pSql, tSQLExpr* pExpr, int16_
   STagCond* pTagCond = &pSql->cmd.tagCond;
   pTagCond->tbnameCond.uid = pMeterMetaInfo->pMeterMeta->uid;
 
-  SString* pTableCond = &pCmd->tagCond.tbnameCond.cond;
-  SStringAlloc(pTableCond, 4096);
-
   assert(pExpr->nSQLOptr == TK_LIKE || pExpr->nSQLOptr == TK_IN);
 
   if (pExpr->nSQLOptr == TK_LIKE) {
-    strcpy(pTableCond->z, tmpTableCondBuf);
-    pTableCond->n = strlen(pTableCond->z);
+    char* str = taosStringBuilderGetResult(sb, NULL);
+    pCmd->tagCond.tbnameCond.cond = strdup(str);
     return TSDB_CODE_SUCCESS;
   }
 
-  strcpy(pTableCond->z, QUERY_COND_REL_PREFIX_IN);
-  pTableCond->n += strlen(QUERY_COND_REL_PREFIX_IN);
+  SStringBuilder sb1 = {0};
+  taosStringBuilderAppendStringLen(&sb1, QUERY_COND_REL_PREFIX_IN, QUERY_COND_REL_PREFIX_IN_LEN);
 
   char db[TSDB_METER_ID_LEN] = {0};
 
   // remove the duplicated input table names
   int32_t num = 0;
-  char**  segments = strsplit(tmpTableCondBuf + QUERY_COND_REL_PREFIX_IN_LEN, TBNAME_LIST_SEP, &num);
-  qsort(segments, num, sizeof(void*), tableNameCompar);
+  char* tableNameString = taosStringBuilderGetResult(sb, NULL);
+  
+  char**  segments = strsplit(tableNameString + QUERY_COND_REL_PREFIX_IN_LEN, TBNAME_LIST_SEP, &num);
+  qsort(segments, num, POINTER_BYTES, tableNameCompar);
 
   int32_t j = 1;
   for (int32_t i = 1; i < num; ++i) {
@@ -3875,25 +3869,30 @@ static int32_t setTableCondForMetricQuery(SSqlObj* pSql, tSQLExpr* pExpr, int16_
   char*     acc = getAccountId(pSql);
 
   for (int32_t i = 0; i < num; ++i) {
-    SStringEnsureRemain(pTableCond, TSDB_METER_ID_LEN);
-
     if (i >= 1) {
-      pTableCond->z[pTableCond->n++] = TBNAME_LIST_SEP[0];
+      taosStringBuilderAppendStringLen(&sb1, TBNAME_LIST_SEP, 1);
     }
-
+    
+    char idBuf[TSDB_METER_ID_LEN + 1] = {0};
     int32_t   xlen = strlen(segments[i]);
     SSQLToken t = {.z = segments[i], .n = xlen, .type = TK_STRING};
 
-    int32_t ret = setObjFullName(pTableCond->z + pTableCond->n, acc, &dbToken, &t, &xlen);
+    int32_t ret = setObjFullName(idBuf, acc, &dbToken, &t, &xlen);
     if (ret != TSDB_CODE_SUCCESS) {
+      taosStringBuilderDestroy(&sb1);
       tfree(segments);
+      
       invalidSqlErrMsg(pCmd, msg);
       return ret;
     }
-
-    pTableCond->n += xlen;
+    
+    taosStringBuilderAppendString(&sb1, idBuf);
   }
-
+  
+  char* str = taosStringBuilderGetResult(&sb1, NULL);
+  pCmd->tagCond.tbnameCond.cond = strdup(str);
+  
+  taosStringBuilderDestroy(&sb1);
   tfree(segments);
   return TSDB_CODE_SUCCESS;
 }
@@ -4071,10 +4070,9 @@ int32_t doParseWhereClause(SSqlObj* pSql, tSQLExpr** pExpr, SCondExpr* condExpr)
   SSqlCmd* pCmd = &pSql->cmd;
 
   /*
-   * tags query condition may be larger than 512bytes,
-   * therefore, we need to prepare enough large space
+   * tags query condition may be larger than 512bytes, therefore, we need to prepare enough large space
    */
-  char tableNameCond[TSDB_MAX_SQL_LEN] = {0};
+  SStringBuilder sb = {0};
 
   int32_t ret = TSDB_CODE_SUCCESS;
   if ((ret = getQueryCondExpr(pCmd, pExpr, condExpr, &type, (*pExpr)->nSQLOptr)) != TSDB_CODE_SUCCESS) {
@@ -4119,7 +4117,7 @@ int32_t doParseWhereClause(SSqlObj* pSql, tSQLExpr** pExpr, SCondExpr* condExpr)
   }
 
   // 4. get the table name query condition
-  if ((ret = getTablenameCond(pCmd, condExpr->pTableCond, tableNameCond)) != TSDB_CODE_SUCCESS) {
+  if ((ret = getTablenameCond(pCmd, condExpr->pTableCond, &sb)) != TSDB_CODE_SUCCESS) {
     return ret;
   }
 
@@ -4135,7 +4133,10 @@ int32_t doParseWhereClause(SSqlObj* pSql, tSQLExpr** pExpr, SCondExpr* condExpr)
 
   // 7. query condition for table name
   pCmd->tagCond.relType = (condExpr->relType == TK_AND) ? TSDB_RELATION_AND : TSDB_RELATION_OR;
-  ret = setTableCondForMetricQuery(pSql, condExpr->pTableCond, condExpr->tableCondIndex, tableNameCond);
+  
+  ret = setTableCondForMetricQuery(pSql, condExpr->pTableCond, condExpr->tableCondIndex, &sb);
+  taosStringBuilderDestroy(&sb);
+  
   if (!validateFilterExpr(pCmd)) {
     return invalidSqlErrMsg(pCmd, msg);
   }
@@ -5156,7 +5157,7 @@ void addGroupInfoForSubquery(SSqlObj* pParentObj, SSqlObj* pSql, int32_t tableIn
 
     if (pExpr->functionId != TSDB_FUNC_TAG) {
       SMeterMetaInfo* pMeterMetaInfo = tscGetMeterMetaInfo(&pSql->cmd, 0);
-      int16_t         columnInfo = tscGetJoinTagColIndexByUid(pCmd, pMeterMetaInfo->pMeterMeta->uid);
+      int16_t         columnInfo = tscGetJoinTagColIndexByUid(&pCmd->tagCond, pMeterMetaInfo->pMeterMeta->uid);
       SColumnIndex    index = {.tableIndex = 0, .columnIndex = columnInfo};
       SSchema*        pSchema = tsGetTagSchema(pMeterMetaInfo->pMeterMeta);
 
diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index d25b2dde53b4456c0127a3a340c6a0e334451712..bf175c55405d940e0d8da9e6552436193c13d0f5 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -689,7 +689,7 @@ int32_t tscLaunchJoinSubquery(SSqlObj *pSql, int16_t tableIndex, int16_t vnodeId
     SSqlExpr *pExpr = tscSqlExprGet(&pNew->cmd, 0);
 
     SMeterMetaInfo *pMeterMetaInfo = tscGetMeterMetaInfo(&pNew->cmd, 0);
-    int16_t         tagColIndex = tscGetJoinTagColIndexByUid(&pNew->cmd, pMeterMetaInfo->pMeterMeta->uid);
+    int16_t         tagColIndex = tscGetJoinTagColIndexByUid(&pSupporter->tagCond, pMeterMetaInfo->pMeterMeta->uid);
 
     pExpr->param->i64Key = tagColIndex;
     pExpr->numOfParams = 1;
@@ -2741,10 +2741,14 @@ static int32_t tscEstimateMetricMetaMsgSize(SSqlCmd *pCmd) {
 
   int32_t n = 0;
   for (int32_t i = 0; i < pCmd->tagCond.numOfTagCond; ++i) {
-    n += pCmd->tagCond.cond[i].cond.n;
+    n += strlen(pCmd->tagCond.cond[i].cond);
   }
 
-  int32_t tagLen = n * TSDB_NCHAR_SIZE + pCmd->tagCond.tbnameCond.cond.n * TSDB_NCHAR_SIZE;
+  int32_t tagLen = n * TSDB_NCHAR_SIZE;
+  if (pCmd->tagCond.tbnameCond.cond != NULL) {
+   tagLen += strlen(pCmd->tagCond.tbnameCond.cond) * TSDB_NCHAR_SIZE;
+  }
+  
   int32_t joinCondLen = (TSDB_METER_ID_LEN + sizeof(int16_t)) * 2;
   int32_t elemSize = sizeof(SMetricMetaElemMsg) * pCmd->numOfTables;
 
@@ -2816,8 +2820,9 @@ int tscBuildMetricMetaMsg(SSqlObj *pSql) {
     if (pTagCond->numOfTagCond > 0) {
       SCond *pCond = tsGetMetricQueryCondPos(pTagCond, uid);
       if (pCond != NULL) {
-        condLen = pCond->cond.n + 1;
-        bool ret = taosMbsToUcs4(pCond->cond.z, pCond->cond.n, pMsg, pCond->cond.n * TSDB_NCHAR_SIZE);
+        condLen = strlen(pCond->cond) + 1;
+        
+        bool ret = taosMbsToUcs4(pCond->cond, condLen, pMsg, condLen * TSDB_NCHAR_SIZE);
         if (!ret) {
           tscError("%p mbs to ucs4 failed:%s", pSql, tsGetMetricQueryCondPos(pTagCond, uid));
           return 0;
@@ -2836,15 +2841,17 @@ int tscBuildMetricMetaMsg(SSqlObj *pSql) {
       offset = pMsg - (char *)pMetaMsg;
 
       pElem->tableCond = htonl(offset);
-      pElem->tableCondLen = htonl(pTagCond->tbnameCond.cond.n);
+      
+      uint32_t len = strlen(pTagCond->tbnameCond.cond);
+      pElem->tableCondLen = htonl(len);
 
-      memcpy(pMsg, pTagCond->tbnameCond.cond.z, pTagCond->tbnameCond.cond.n);
-      pMsg += pTagCond->tbnameCond.cond.n;
+      memcpy(pMsg, pTagCond->tbnameCond.cond, len);
+      pMsg += len;
     }
 
     SSqlGroupbyExpr *pGroupby = &pCmd->groupbyExpr;
 
-    if (pGroupby->tableIndex != i) {
+    if (pGroupby->tableIndex != i && pGroupby->numOfGroupCols > 0) {
       pElem->orderType = 0;
       pElem->orderIndex = 0;
       pElem->numOfGroupCols = 0;
diff --git a/src/client/src/tscSql.c b/src/client/src/tscSql.c
index 233a37dc5930f8b5d16d608882ced99148493c4f..4d7f2734a940500f04af0c2cf1abb4ac8f6e6335 100644
--- a/src/client/src/tscSql.c
+++ b/src/client/src/tscSql.c
@@ -270,7 +270,7 @@ int taos_query(TAOS *taos, const char *sqlstr) {
   SSqlRes *pRes = &pSql->res;
 
   size_t sqlLen = strlen(sqlstr);
-  if (sqlLen > TSDB_MAX_SQL_LEN) {
+  if (sqlLen > tsMaxSQLStringLen) {
     pRes->code = tscInvalidSQLErrMsg(pSql->cmd.payload, "sql too long", NULL);  // set the additional error msg for invalid sql
     tscError("%p SQL result:%d, %s pObj:%p", pSql, pRes->code, taos_errstr(taos), pObj);
     
@@ -786,7 +786,6 @@ int taos_errno(TAOS *taos) {
 char *taos_errstr(TAOS *taos) {
   STscObj *pObj = (STscObj *)taos;
   uint8_t  code;
-//  char          temp[256] = {0};
 
   if (pObj == NULL || pObj->signature != pObj) return tsError[globalCode];
 
@@ -797,11 +796,13 @@ char *taos_errstr(TAOS *taos) {
 
   // for invalid sql, additional information is attached to explain why the sql is invalid
   if (code == TSDB_CODE_INVALID_SQL) {
-//    snprintf(temp, tListLen(temp), "invalid SQL: %s", pObj->pSql->cmd.payload);
-//    strcpy(pObj->pSql->cmd.payload, temp);
     return pObj->pSql->cmd.payload;
   } else {
-    return tsError[code];
+    if (code < 0 || code > TSDB_CODE_MAX_ERROR_CODE) {
+      return tsError[TSDB_CODE_SUCCESS];
+    } else {
+      return tsError[code];
+    }
   }
 }
 
@@ -924,7 +925,7 @@ int taos_validate_sql(TAOS *taos, const char *sql) {
   tscTrace("%p Valid SQL: %s pObj:%p", pSql, sql, pObj);
 
   int32_t sqlLen = strlen(sql);
-  if (sqlLen > TSDB_MAX_SQL_LEN) {
+  if (sqlLen > tsMaxSQLStringLen) {
     tscError("%p sql too long", pSql);
     pRes->code = TSDB_CODE_INVALID_SQL;
     return pRes->code;
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index baafb57f6a57b924b22abe71460ed5cd034ff853..7fd3d7706bc4bf7234593b29f51bff7fc04f417d 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -51,7 +51,6 @@ void tscGetMetricMetaCacheKey(SSqlCmd* pCmd, char* str, uint64_t uid) {
   assert(len < tListLen(tagIdBuf));
 
   const int32_t maxKeySize = TSDB_MAX_TAGS_LEN;  // allowed max key size
-  char*         tmp = calloc(1, TSDB_MAX_SQL_LEN);
 
   SCond* cond = tsGetMetricQueryCondPos(pTagCond, uid);
 
@@ -60,12 +59,24 @@ void tscGetMetricMetaCacheKey(SSqlCmd* pCmd, char* str, uint64_t uid) {
     sprintf(join, "%s,%s", pTagCond->joinInfo.left.meterId, pTagCond->joinInfo.right.meterId);
   }
 
-  int32_t keyLen =
-      snprintf(tmp, TSDB_MAX_SQL_LEN, "%s,%s,%s,%d,%s,[%s],%d", pMeterMetaInfo->name,
-               (cond != NULL ? cond->cond.z : NULL), pTagCond->tbnameCond.cond.n > 0 ? pTagCond->tbnameCond.cond.z : NULL,
+  // estimate the buffer size
+  size_t tbnameCondLen = pTagCond->tbnameCond.cond != NULL? strlen(pTagCond->tbnameCond.cond):0;
+  size_t redundantLen = 20;
+  
+  size_t bufSize = strlen(pMeterMetaInfo->name) + tbnameCondLen + strlen(join) + strlen(tagIdBuf);
+  if (cond != NULL) {
+    bufSize += strlen(cond->cond);
+  }
+  
+  bufSize = (size_t) ((bufSize + redundantLen) * 1.5);
+  char* tmp = calloc(1, bufSize);
+
+  int32_t keyLen = snprintf(tmp, bufSize, "%s,%s,%s,%d,%s,[%s],%d", pMeterMetaInfo->name,
+               (cond != NULL ? cond->cond : NULL),
+               (tbnameCondLen > 0 ? pTagCond->tbnameCond.cond : NULL),
                pTagCond->relType, join, tagIdBuf, pCmd->groupbyExpr.orderType);
 
-  assert(keyLen <= TSDB_MAX_SQL_LEN);
+  assert(keyLen <= bufSize);
 
   if (keyLen < maxKeySize) {
     strcpy(str, tmp);
@@ -99,7 +110,7 @@ void tsSetMetricQueryCond(STagCond* pTagCond, uint64_t uid, const char* str) {
 
   SCond* pDest = &pTagCond->cond[pTagCond->numOfTagCond];
   pDest->uid = uid;
-  pDest->cond = SStringCreate(str);
+  pDest->cond = strdup(str);
 
   pTagCond->numOfTagCond += 1;
 }
@@ -1340,14 +1351,20 @@ bool tscValidateColumnId(SSqlCmd* pCmd, int32_t colId) {
 
 void tscTagCondCopy(STagCond* dest, const STagCond* src) {
   memset(dest, 0, sizeof(STagCond));
+  
+  if (src->tbnameCond.cond != NULL) {
+    dest->tbnameCond.cond = strdup(src->tbnameCond.cond);
+  }
 
-  SStringCopy(&dest->tbnameCond.cond, &src->tbnameCond.cond);
   dest->tbnameCond.uid = src->tbnameCond.uid;
 
   memcpy(&dest->joinInfo, &src->joinInfo, sizeof(SJoinInfo));
 
   for (int32_t i = 0; i < src->numOfTagCond; ++i) {
-    SStringCopy(&dest->cond[i].cond, &src->cond[i].cond);
+    if (src->cond[i].cond != NULL) {
+      dest->cond[i].cond = strdup(src->cond[i].cond);
+    }
+    
     dest->cond[i].uid = src->cond[i].uid;
   }
 
@@ -1356,10 +1373,9 @@ void tscTagCondCopy(STagCond* dest, const STagCond* src) {
 }
 
 void tscTagCondRelease(STagCond* pCond) {
-  SStringFree(&pCond->tbnameCond.cond);
-
+  free(pCond->tbnameCond.cond);
   for (int32_t i = 0; i < pCond->numOfTagCond; ++i) {
-    SStringFree(&pCond->cond[i].cond);
+    free(pCond->cond[i].cond);
   }
 
   memset(pCond, 0, sizeof(STagCond));
@@ -1571,123 +1587,6 @@ void tscResetForNextRetrieve(SSqlRes* pRes) {
   pRes->numOfRows = 0;
 }
 
-SString SStringCreate(const char* str) {
-  size_t len = strlen(str);
-
-  SString dest = {.n = len, .alloc = len + 1};
-  dest.z = calloc(1, dest.alloc);
-  strcpy(dest.z, str);
-
-  return dest;
-}
-
-void SStringCopy(SString* pDest, const SString* pSrc) {
-  if (pSrc->n > 0) {
-    pDest->n = pSrc->n;
-    pDest->alloc = pDest->n + 1;  // one additional space for null terminate
-
-    pDest->z = calloc(1, pDest->alloc);
-
-    memcpy(pDest->z, pSrc->z, pDest->n);
-  } else {
-    memset(pDest, 0, sizeof(SString));
-  }
-}
-
-void SStringFree(SString* pStr) {
-  if (pStr->alloc > 0) {
-    tfree(pStr->z);
-    pStr->alloc = 0;
-  }
-}
-
-void SStringShrink(SString* pStr) {
-  if (pStr->alloc > (pStr->n + 1) && pStr->alloc > (pStr->n * 2)) {
-    pStr->z = realloc(pStr->z, pStr->n + 1);
-    assert(pStr->z != NULL);
-
-    pStr->alloc = pStr->n + 1;
-  }
-}
-
-int32_t SStringAlloc(SString* pStr, int32_t size) {
-  if (pStr->alloc >= size) {
-    return TSDB_CODE_SUCCESS;
-  }
-
-  size = ALIGN8(size);
-
-  char* tmp = NULL;
-  if (pStr->z != NULL) {
-    tmp = realloc(pStr->z, size);
-    memset(pStr->z + pStr->n, 0, size - pStr->n);
-  } else {
-    tmp = calloc(1, size);
-  }
-
-  if (tmp == NULL) {
-#ifdef WINDOWS
-    LPVOID lpMsgBuf;
-    FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL,
-                  GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),  // Default language
-                  (LPTSTR)&lpMsgBuf, 0, NULL);
-    tscTrace("failed to allocate memory, reason:%s", lpMsgBuf);
-    LocalFree(lpMsgBuf);
-#else
-    char errmsg[256] = {0};
-    strerror_r(errno, errmsg, tListLen(errmsg));
-    tscTrace("failed to allocate memory, reason:%s", errmsg);
-#endif
-    return TSDB_CODE_CLI_OUT_OF_MEMORY;
-  }
-
-  pStr->z = tmp;
-  pStr->alloc = size;
-
-  return TSDB_CODE_SUCCESS;
-}
-
-#define MIN_ALLOC_SIZE 8
-
-int32_t SStringEnsureRemain(SString* pStr, int32_t size) {
-  if (pStr->alloc - pStr->n > size) {
-    return TSDB_CODE_SUCCESS;
-  }
-
-  // remain space is insufficient, allocate more spaces
-  int32_t inc = (size >= MIN_ALLOC_SIZE) ? size : MIN_ALLOC_SIZE;
-  if (inc < (pStr->alloc >> 1)) {
-    inc = (pStr->alloc >> 1);
-  }
-
-  // get the new size
-  int32_t newsize = pStr->alloc + inc;
-
-  char* tmp = realloc(pStr->z, newsize);
-  if (tmp == NULL) {
-#ifdef WINDOWS
-    LPVOID lpMsgBuf;
-    FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL,
-                  GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),  // Default language
-                  (LPTSTR)&lpMsgBuf, 0, NULL);
-    tscTrace("failed to allocate memory, reason:%s", lpMsgBuf);
-    LocalFree(lpMsgBuf);
-#else
-    char errmsg[256] = {0};
-    strerror_r(errno, errmsg, tListLen(errmsg));
-    tscTrace("failed to allocate memory, reason:%s", errmsg);
-#endif
-
-    return TSDB_CODE_CLI_OUT_OF_MEMORY;
-  }
-
-  memset(tmp + pStr->n, 0, inc);
-  pStr->alloc = newsize;
-  pStr->z = tmp;
-
-  return TSDB_CODE_SUCCESS;
-}
-
 SSqlObj* createSubqueryObj(SSqlObj* pSql, int32_t vnodeIndex, int16_t tableIndex, void (*fp)(), void* param,
                            SSqlObj* pPrevSql) {
   SSqlCmd* pCmd = &pSql->cmd;
@@ -1822,9 +1721,7 @@ void tscDoQuery(SSqlObj* pSql) {
   }
 }
 
-int16_t tscGetJoinTagColIndexByUid(SSqlCmd* pCmd, uint64_t uid) {
-  STagCond* pTagCond = &pCmd->tagCond;
-
+int16_t tscGetJoinTagColIndexByUid(STagCond* pTagCond, uint64_t uid) {
   if (pTagCond->joinInfo.left.uid == uid) {
     return pTagCond->joinInfo.left.tagCol;
   } else {
diff --git a/src/inc/taoserror.h b/src/inc/taoserror.h
index 5510212dbc37f6ce3ebb33c43d34ca93fc0649c1..5fee1d7da563eac57f3cb482ca12869e2b8bafe7 100644
--- a/src/inc/taoserror.h
+++ b/src/inc/taoserror.h
@@ -128,7 +128,7 @@ extern "C" {
 #define TSDB_CODE_CACHE_BLOCK_TS_DISORDERED  107      // time stamp in cache block is disordered
 #define TSDB_CODE_FILE_BLOCK_TS_DISORDERED   108      // time stamp in file block is disordered
 #define TSDB_CODE_INVALID_COMMIT_LOG         109      // commit log init failed
-#define TSDB_CODE_SERVER_NO_SPACE            110
+#define TSDB_CODE_SERV_NO_DISKSPACE          110
 #define TSDB_CODE_NOT_SUPER_TABLE            111      // operation only available for super table
 #define TSDB_CODE_DUPLICATE_TAGS             112      // tags value for join not unique
 #define TSDB_CODE_INVALID_SUBMIT_MSG         113
@@ -137,6 +137,8 @@ extern "C" {
 #define TSDB_CODE_INVALID_VNODE_STATUS       116
 #define TSDB_CODE_FAILED_TO_LOCK_RESOURCES   117
 
+#define TSDB_CODE_MAX_ERROR_CODE             118
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/inc/tglobalcfg.h b/src/inc/tglobalcfg.h
index ede3c97ce9f874152e8b81d78b6b1b19adc49b49..ed91964d611ccd4e578007794fcf9c9940123cf0 100644
--- a/src/inc/tglobalcfg.h
+++ b/src/inc/tglobalcfg.h
@@ -106,7 +106,6 @@ extern int  tsMaxDbs;
 extern int  tsMaxTables;
 extern int  tsMaxDnodes;
 extern int  tsMaxVGroups;
-extern int  tsShellActivityTimer;
 extern char tsMgmtZone[];
 
 extern char tsLocalIp[];
@@ -127,6 +126,7 @@ extern int tsEnableHttpModule;
 extern int tsEnableMonitorModule;
 extern int tsRestRowLimit;
 extern int tsCompressMsgSize;
+extern int tsMaxSQLStringLen;
 
 extern char tsSocketType[4];
 
diff --git a/src/inc/tsdb.h b/src/inc/tsdb.h
index 8b057654c68a4c8f39bf541e07f1e171ebed0091..1190dc8420fe360a667c2d932cfc8a20e4321015 100644
--- a/src/inc/tsdb.h
+++ b/src/inc/tsdb.h
@@ -100,6 +100,7 @@ extern "C" {
 #define TSDB_COL_NAME_LEN         64
 #define TSDB_MAX_SAVED_SQL_LEN    TSDB_MAX_COLUMNS * 16
 #define TSDB_MAX_SQL_LEN          TSDB_PAYLOAD_SIZE
+#define TSDB_MAX_ALLOWED_SQL_LEN  (8*1024*1024U)          // sql length should be less than 6mb
 
 #define TSDB_MAX_BYTES_PER_ROW    TSDB_MAX_COLUMNS * 16
 #define TSDB_MAX_TAGS_LEN         512
diff --git a/src/rpc/src/tstring.c b/src/rpc/src/tstring.c
index e3daca130a83c1c363dad3eeb9bef1d2394842b2..63f65b882f59b07b434d908e33aba455c43b5178 100644
--- a/src/rpc/src/tstring.c
+++ b/src/rpc/src/tstring.c
@@ -238,7 +238,7 @@ char *tsError[] = {"success",
                    "only super table has metric meta info",
                    "tags value not unique for join",
                    "invalid submit message",
-                   "not active table(not created yet or deleted already)",  //114
+                   "not active table(not created yet or dropped already)",  //114
                    "invalid table id",
                    "invalid vnode status",    //116
                    "failed to lock resources",
diff --git a/src/system/detail/inc/vnodeQueryImpl.h b/src/system/detail/inc/vnodeQueryImpl.h
index 35279ca011f1a8aeec012e1d2311862dde2f95ca..2002483f03136fcc65d0bb1727ac169d12473db7 100644
--- a/src/system/detail/inc/vnodeQueryImpl.h
+++ b/src/system/detail/inc/vnodeQueryImpl.h
@@ -27,7 +27,13 @@ extern "C" {
 #define GET_QINFO_ADDR(x)    ((char*)(x)-offsetof(SQInfo, query))
 #define Q_STATUS_EQUAL(p, s) (((p) & (s)) != 0)
 
+/*
+ * set the output buffer page size is 16k
+ * The page size should be sufficient for at least one output result or intermediate result.
+ * Some intermediate results may be extremely large, such as top/bottom(100) query.
+ */
 #define DEFAULT_INTERN_BUF_SIZE            16384L
+
 #define INIT_ALLOCATE_DISK_PAGES           60L
 #define DEFAULT_DATA_FILE_MAPPING_PAGES    2L
 #define DEFAULT_DATA_FILE_MMAP_WINDOW_SIZE (DEFAULT_DATA_FILE_MAPPING_PAGES * DEFAULT_INTERN_BUF_SIZE)
@@ -160,7 +166,7 @@ void pointInterpSupporterDestroy(SPointInterpoSupporter* pPointInterpSupport);
 void pointInterpSupporterSetData(SQInfo* pQInfo, SPointInterpoSupporter* pPointInterpSupport);
 
 int64_t loadRequiredBlockIntoMem(SQueryRuntimeEnv* pRuntimeEnv, SPositionInfo* position);
-void doCloseAllOpenedResults(SMeterQuerySupportObj* pSupporter);
+int32_t doCloseAllOpenedResults(SMeterQuerySupportObj* pSupporter);
 void disableFunctForSuppleScan(SQueryRuntimeEnv* pRuntimeEnv, int32_t order);
 void enableFunctForMasterScan(SQueryRuntimeEnv* pRuntimeEnv, int32_t order);
 
@@ -185,7 +191,7 @@ void freeMeterBlockInfoEx(SMeterDataBlockInfoEx* pDataBlockInfoEx, int32_t len);
 
 void setExecutionContext(SMeterQuerySupportObj* pSupporter, SOutputRes* outputRes, int32_t meterIdx, int32_t groupIdx,
                          SMeterQueryInfo* sqinfo);
-void setIntervalQueryExecutionContext(SMeterQuerySupportObj* pSupporter, int32_t meterIdx, SMeterQueryInfo* sqinfo);
+int32_t setIntervalQueryExecutionContext(SMeterQuerySupportObj* pSupporter, int32_t meterIdx, SMeterQueryInfo* sqinfo);
 
 int64_t getQueryStartPositionInCache(SQueryRuntimeEnv* pRuntimeEnv, int32_t* slot, int32_t* pos, bool ignoreQueryRange);
 int64_t getNextAccessedKeyInData(SQuery* pQuery, int64_t* pPrimaryCol, SBlockInfo* pBlockInfo, int32_t blockStatus);
@@ -224,11 +230,11 @@ void changeMeterQueryInfoForSuppleQuery(SMeterQueryInfo *pMeterQueryInfo, TSKEY
 /**
  * add the new allocated disk page to meter query info
  * the new allocated disk page is used to keep the intermediate (interval) results
- *
+ * @param pQuery
  * @param pMeterQueryInfo
  * @param pSupporter
  */
-tFilePage* addDataPageForMeterQueryInfo(SMeterQueryInfo *pMeterQueryInfo, SMeterQuerySupportObj *pSupporter);
+tFilePage* addDataPageForMeterQueryInfo(SQuery* pQuery, SMeterQueryInfo *pMeterQueryInfo, SMeterQuerySupportObj *pSupporter);
 
 /**
  * save the query range data into SMeterQueryInfo
diff --git a/src/system/detail/src/vnodeQueryImpl.c b/src/system/detail/src/vnodeQueryImpl.c
index 9620ab38dcbc357f1649a9b909b1abecb4c73233..5174753d8224a15b20af798844e50057cc13b2ce 100644
--- a/src/system/detail/src/vnodeQueryImpl.c
+++ b/src/system/detail/src/vnodeQueryImpl.c
@@ -67,13 +67,13 @@ static void doApplyIntervalQueryOnBlock(SMeterQuerySupportObj *pSupporter, SMete
                                         SBlockInfo *pBlockInfo, int64_t *pPrimaryCol, char *sdata, SField *pFields,
                                         __block_search_fn_t searchFn);
 
-static void saveResult(SMeterQuerySupportObj *pSupporter, SMeterQueryInfo *pMeterQueryInfo, int32_t numOfResult);
+static int32_t saveResult(SMeterQuerySupportObj *pSupporter, SMeterQueryInfo *pMeterQueryInfo, int32_t numOfResult);
 static void applyIntervalQueryOnBlock(SMeterQuerySupportObj *pSupporter, SMeterDataInfo *pInfoEx, char *data,
                                       int64_t *pPrimaryData, SBlockInfo *pBlockInfo, int32_t blockStatus,
                                       SField *pFields, __block_search_fn_t searchFn);
 
 static void resetMergeResultBuf(SQuery *pQuery, SQLFunctionCtx *pCtx);
-static void flushFromResultBuf(SMeterQuerySupportObj *pSupporter, const SQuery *pQuery,
+static int32_t flushFromResultBuf(SMeterQuerySupportObj *pSupporter, const SQuery *pQuery,
                                const SQueryRuntimeEnv *pRuntimeEnv);
 static void validateTimestampForSupplementResult(SQueryRuntimeEnv *pRuntimeEnv, int64_t numOfIncrementRes);
 static void getBasicCacheInfoSnapshot(SQuery *pQuery, SCacheInfo *pCacheInfo, int32_t vid);
@@ -413,7 +413,7 @@ char *vnodeGetHeaderFileData(SQueryRuntimeEnv *pRuntimeEnv, int32_t vnodeId, int
     vnodeSetOpenedFileNames(pVnodeFileInfo);
     
     if (doOpenQueryFileData(pQInfo, pVnodeFileInfo, vnodeId) != TSDB_CODE_SUCCESS) {
-      doCloseOpenedFileData(pVnodeFileInfo);  // there may be partially open fd, close it anyway.
+      doCloseOpenedFileData(pVnodeFileInfo);  // all the fds may be partially opened, close them anyway.
       return pVnodeFileInfo->pHeaderFileData;
     }
   }
@@ -1291,9 +1291,6 @@ static int32_t blockwiseApplyAllFunctions(SQueryRuntimeEnv *pRuntimeEnv, int32_t
 
   for (int32_t k = 0; k < pQuery->numOfOutputCols; ++k) {
     int32_t functionId = pQuery->pSelectExpr[k].pBase.functionId;
-    //    if (!functionNeedToExecute(pRuntimeEnv, &pCtx[k], functionId)) {
-    //      continue;
-    //    }
 
     SField dummyField = {0};
 
@@ -3052,7 +3049,7 @@ static void vnodeRecordAllFiles(SQInfo *pQInfo, int32_t vnodeId) {
   sprintf(pVnodeFilesInfo->dbFilePathPrefix, "%s/vnode%d/db/", tsDirectory, vnodeId);
   DIR *pDir = opendir(pVnodeFilesInfo->dbFilePathPrefix);
   if (pDir == NULL) {
-    dError("QInfo:%p failed to open directory:%s", pQInfo, pVnodeFilesInfo->dbFilePathPrefix);
+    dError("QInfo:%p failed to open directory:%s, %s", pQInfo, pVnodeFilesInfo->dbFilePathPrefix, strerror(errno));
     return;
   }
 
@@ -3920,11 +3917,16 @@ int32_t vnodeMultiMeterQueryPrepare(SQInfo *pQInfo, SQuery *pQuery, void *param)
       dError("QInfo:%p failed to create file: %s on disk. %s", pQInfo, pSupporter->extBufFile, strerror(errno));
       return TSDB_CODE_SERV_OUT_OF_MEMORY;
     }
-
-    // set 4k page for each meter
+    
     pSupporter->numOfPages = pSupporter->numOfMeters;
 
-    ftruncate(pSupporter->meterOutputFd, pSupporter->numOfPages * DEFAULT_INTERN_BUF_SIZE);
+    ret = ftruncate(pSupporter->meterOutputFd, pSupporter->numOfPages * DEFAULT_INTERN_BUF_SIZE);
+    if (ret != TSDB_CODE_SUCCESS) {
+      dError("QInfo:%p failed to create intermediate result output file:%s. %s", pQInfo, pSupporter->extBufFile,
+          strerror(errno));
+      return TSDB_CODE_SERV_NO_DISKSPACE;
+    }
+    
     pSupporter->runtimeEnv.numOfRowsPerPage = (DEFAULT_INTERN_BUF_SIZE - sizeof(tFilePage)) / pQuery->rowSize;
     pSupporter->lastPageId = -1;
     pSupporter->bufSize = pSupporter->numOfPages * DEFAULT_INTERN_BUF_SIZE;
@@ -3932,7 +3934,7 @@ int32_t vnodeMultiMeterQueryPrepare(SQInfo *pQInfo, SQuery *pQuery, void *param)
     pSupporter->meterOutputMMapBuf =
         mmap(NULL, pSupporter->bufSize, PROT_READ | PROT_WRITE, MAP_SHARED, pSupporter->meterOutputFd, 0);
     if (pSupporter->meterOutputMMapBuf == MAP_FAILED) {
-      dError("QInfo:%p failed to map data file: %s to disk. %s", pQInfo, pSupporter->extBufFile, strerror(errno));
+      dError("QInfo:%p failed to map temp file: %s. %s", pQInfo, pSupporter->extBufFile, strerror(errno));
       return TSDB_CODE_SERV_OUT_OF_MEMORY;
     }
   }
@@ -4733,20 +4735,24 @@ int32_t mergeMetersResultToOneGroups(SMeterQuerySupportObj *pSupporter) {
   SQuery *          pQuery = pRuntimeEnv->pQuery;
 
   int64_t st = taosGetTimestampMs();
+  int32_t ret = TSDB_CODE_SUCCESS;
 
   while (pSupporter->subgroupIdx < pSupporter->pSidSet->numOfSubSet) {
     int32_t start = pSupporter->pSidSet->starterPos[pSupporter->subgroupIdx];
     int32_t end = pSupporter->pSidSet->starterPos[pSupporter->subgroupIdx + 1];
 
-    int32_t ret =
-        doMergeMetersResultsToGroupRes(pSupporter, pQuery, pRuntimeEnv, pSupporter->pMeterDataInfo, start, end);
+    ret = doMergeMetersResultsToGroupRes(pSupporter, pQuery, pRuntimeEnv, pSupporter->pMeterDataInfo, start, end);
+    if (ret < 0) {       // not enough disk space to save the data into disk
+      return -1;
+    }
+    
     pSupporter->subgroupIdx += 1;
 
-    /* this group generates at least one result, return results */
+    // this group generates at least one result, return results
     if (ret > 0) {
       break;
     }
-
+    
     assert(pSupporter->numOfGroupResultPages == 0);
     dTrace("QInfo:%p no result in group %d, continue", GET_QINFO_ADDR(pQuery), pSupporter->subgroupIdx - 1);
   }
@@ -4754,7 +4760,7 @@ int32_t mergeMetersResultToOneGroups(SMeterQuerySupportObj *pSupporter) {
   dTrace("QInfo:%p merge res data into group, index:%d, total group:%d, elapsed time:%lldms", GET_QINFO_ADDR(pQuery),
          pSupporter->subgroupIdx - 1, pSupporter->pSidSet->numOfSubSet, taosGetTimestampMs() - st);
 
-  return pSupporter->numOfGroupResultPages;
+  return TSDB_CODE_SUCCESS;
 }
 
 void copyResToQueryResultBuf(SMeterQuerySupportObj *pSupporter, SQuery *pQuery) {
@@ -4762,7 +4768,9 @@ void copyResToQueryResultBuf(SMeterQuerySupportObj *pSupporter, SQuery *pQuery)
     pSupporter->numOfGroupResultPages = 0;
 
     // current results of group has been sent to client, try next group
-    mergeMetersResultToOneGroups(pSupporter);
+    if (mergeMetersResultToOneGroups(pSupporter) != TSDB_CODE_SUCCESS) {
+      return;      // failed to save data in the disk
+    }
 
     // set current query completed
     if (pSupporter->numOfGroupResultPages == 0 && pSupporter->subgroupIdx == pSupporter->pSidSet->numOfSubSet) {
@@ -4840,7 +4848,10 @@ int32_t doMergeMetersResultsToGroupRes(SMeterQuerySupportObj *pSupporter, SQuery
     } else {
       // copy data to disk buffer
       if (buffer[0]->numOfElems == pQuery->pointsToRead) {
-        flushFromResultBuf(pSupporter, pQuery, pRuntimeEnv);
+        if (flushFromResultBuf(pSupporter, pQuery, pRuntimeEnv) != TSDB_CODE_SUCCESS) {
+          return -1;
+        }
+        
         resetMergeResultBuf(pQuery, pCtx);
       }
 
@@ -4887,7 +4898,14 @@ int32_t doMergeMetersResultsToGroupRes(SMeterQuerySupportObj *pSupporter, SQuery
   }
 
   if (buffer[0]->numOfElems != 0) {  // there are data in buffer
-    flushFromResultBuf(pSupporter, pQuery, pRuntimeEnv);
+    if (flushFromResultBuf(pSupporter, pQuery, pRuntimeEnv) != TSDB_CODE_SUCCESS) {
+      dError("QInfo:%p failed to flush data into temp file, abort query", GET_QINFO_ADDR(pQuery), pSupporter->extBufFile);
+      tfree(pTree);
+      tfree(pValidMeter);
+      tfree(posArray);
+      
+      return -1;
+    }
   }
 
   int64_t endt = taosGetTimestampMs();
@@ -4906,25 +4924,44 @@ int32_t doMergeMetersResultsToGroupRes(SMeterQuerySupportObj *pSupporter, SQuery
   return pSupporter->numOfGroupResultPages;
 }
 
-static void extendDiskBuf(SMeterQuerySupportObj *pSupporter, int32_t numOfPages) {
+static int32_t extendDiskBuf(const SQuery* pQuery, SMeterQuerySupportObj *pSupporter, int32_t numOfPages) {
   assert(pSupporter->numOfPages * DEFAULT_INTERN_BUF_SIZE == pSupporter->bufSize);
-
+  
+  SQInfo* pQInfo = (SQInfo*) GET_QINFO_ADDR(pQuery);
+  
   int32_t ret = munmap(pSupporter->meterOutputMMapBuf, pSupporter->bufSize);
   pSupporter->numOfPages = numOfPages;
 
-  // disk-based output buffer is exhausted, try to extend the disk-based buffer
+  /*
+   * disk-based output buffer is exhausted, try to extend the disk-based buffer, the available disk space may
+   * be insufficient
+   */
   ret = ftruncate(pSupporter->meterOutputFd, pSupporter->numOfPages * DEFAULT_INTERN_BUF_SIZE);
   if (ret != 0) {
-    perror("error in allocate the disk-based buffer");
-    return;
+    dError("QInfo:%p failed to create intermediate result output file:%s. %s", pQInfo, pSupporter->extBufFile,
+           strerror(errno));
+    pQInfo->code = -TSDB_CODE_SERV_NO_DISKSPACE;
+    pQInfo->killed = 1;
+    
+    return pQInfo->code;
   }
 
   pSupporter->bufSize = pSupporter->numOfPages * DEFAULT_INTERN_BUF_SIZE;
   pSupporter->meterOutputMMapBuf =
       mmap(NULL, pSupporter->bufSize, PROT_READ | PROT_WRITE, MAP_SHARED, pSupporter->meterOutputFd, 0);
+  
+  if (pSupporter->meterOutputMMapBuf == MAP_FAILED) {
+    dError("QInfo:%p failed to map temp file: %s. %s", pQInfo, pSupporter->extBufFile, strerror(errno));
+    pQInfo->code = -TSDB_CODE_SERV_OUT_OF_MEMORY;
+    pQInfo->killed = 1;
+    
+    return pQInfo->code;
+  }
+  
+  return TSDB_CODE_SUCCESS;
 }
 
-void flushFromResultBuf(SMeterQuerySupportObj *pSupporter, const SQuery *pQuery, const SQueryRuntimeEnv *pRuntimeEnv) {
+int32_t flushFromResultBuf(SMeterQuerySupportObj *pSupporter, const SQuery *pQuery, const SQueryRuntimeEnv *pRuntimeEnv) {
   int32_t numOfMeterResultBufPages = pSupporter->lastPageId + 1;
   int64_t dstSize = numOfMeterResultBufPages * DEFAULT_INTERN_BUF_SIZE +
                     pSupporter->groupResultSize * (pSupporter->numOfGroupResultPages + 1);
@@ -4935,7 +4972,9 @@ void flushFromResultBuf(SMeterQuerySupportObj *pSupporter, const SQuery *pQuery,
       requiredPages += pSupporter->numOfMeters;
     }
 
-    extendDiskBuf(pSupporter, requiredPages);
+    if (extendDiskBuf(pQuery, pSupporter, requiredPages) != TSDB_CODE_SUCCESS) {
+      return -1;
+    }
   }
 
   char *lastPosition = pSupporter->meterOutputMMapBuf + DEFAULT_INTERN_BUF_SIZE * numOfMeterResultBufPages +
@@ -4949,6 +4988,7 @@ void flushFromResultBuf(SMeterQuerySupportObj *pSupporter, const SQuery *pQuery,
   }
 
   pSupporter->numOfGroupResultPages += 1;
+  return TSDB_CODE_SUCCESS;
 }
 
 void resetMergeResultBuf(SQuery *pQuery, SQLFunctionCtx *pCtx) {
@@ -4966,7 +5006,7 @@ void setMeterDataInfo(SMeterDataInfo *pMeterDataInfo, SMeterObj *pMeterObj, int3
   pMeterDataInfo->meterOrderIdx = meterIdx;
 }
 
-void doCloseAllOpenedResults(SMeterQuerySupportObj *pSupporter) {
+int32_t doCloseAllOpenedResults(SMeterQuerySupportObj *pSupporter) {
   SQueryRuntimeEnv *pRuntimeEnv = &pSupporter->runtimeEnv;
   SQuery *          pQuery = pRuntimeEnv->pQuery;
 
@@ -4980,11 +5020,20 @@ void doCloseAllOpenedResults(SMeterQuerySupportObj *pSupporter) {
         pRuntimeEnv->pMeterObj = getMeterObj(pSupporter->pMeterObj, pSupporter->pSidSet->pSids[index]->sid);
         assert(pRuntimeEnv->pMeterObj == pMeterInfo[i].pMeterObj);
 
-        setIntervalQueryExecutionContext(pSupporter, i, pMeterInfo[i].pMeterQInfo);
-        saveResult(pSupporter, pMeterInfo[i].pMeterQInfo, pMeterInfo[i].pMeterQInfo->lastResRows);
+        int32_t ret = setIntervalQueryExecutionContext(pSupporter, i, pMeterInfo[i].pMeterQInfo);
+        if (ret != TSDB_CODE_SUCCESS) {
+          return ret;
+        }
+        
+        ret = saveResult(pSupporter, pMeterInfo[i].pMeterQInfo, pMeterInfo[i].pMeterQInfo->lastResRows);
+        if (ret != TSDB_CODE_SUCCESS) {
+          return ret;
+        }
       }
     }
   }
+  
+  return TSDB_CODE_SUCCESS;
 }
 
 void disableFunctForSuppleScan(SQueryRuntimeEnv *pRuntimeEnv, int32_t order) {
@@ -5690,18 +5739,24 @@ void changeMeterQueryInfoForSuppleQuery(SMeterQueryInfo *pMeterQueryInfo, TSKEY
   }
 }
 
-static tFilePage *allocNewPage(SMeterQuerySupportObj *pSupporter, uint32_t *pageId) {
+static tFilePage *allocNewPage(SQuery* pQuery, SMeterQuerySupportObj *pSupporter, uint32_t *pageId) {
   if (pSupporter->lastPageId == pSupporter->numOfPages - 1) {
-    extendDiskBuf(pSupporter, pSupporter->numOfPages + pSupporter->numOfMeters);
+    if (extendDiskBuf(pQuery, pSupporter, pSupporter->numOfPages + pSupporter->numOfMeters) != TSDB_CODE_SUCCESS) {
+      return NULL;
+    }
   }
 
   *pageId = (++pSupporter->lastPageId);
   return getFilePage(pSupporter, *pageId);
 }
 
-tFilePage *addDataPageForMeterQueryInfo(SMeterQueryInfo *pMeterQueryInfo, SMeterQuerySupportObj *pSupporter) {
+tFilePage *addDataPageForMeterQueryInfo(SQuery* pQuery, SMeterQueryInfo *pMeterQueryInfo, SMeterQuerySupportObj *pSupporter) {
   uint32_t   pageId = 0;
-  tFilePage *pPage = allocNewPage(pSupporter, &pageId);
+  
+  tFilePage *pPage = allocNewPage(pQuery, pSupporter, &pageId);
+  if (pPage == NULL) {  // failed to allocate disk-based buffer for intermediate results
+    return NULL;
+  }
 
   if (pMeterQueryInfo->numOfPages >= pMeterQueryInfo->numOfAlloc) {
     pMeterQueryInfo->numOfAlloc = pMeterQueryInfo->numOfAlloc << 1;
@@ -6199,46 +6254,53 @@ void validateTimestampForSupplementResult(SQueryRuntimeEnv *pRuntimeEnv, int64_t
   }
 }
 
-void setOutputBufferForIntervalQuery(SMeterQuerySupportObj *pSupporter, SMeterQueryInfo *pMeterQueryInfo) {
+int32_t setOutputBufferForIntervalQuery(SMeterQuerySupportObj *pSupporter, SMeterQueryInfo *pMeterQueryInfo) {
   SQueryRuntimeEnv *pRuntimeEnv = &pSupporter->runtimeEnv;
   tFilePage *       pData = NULL;
 
+  SQuery* pQuery = pRuntimeEnv->pQuery;
+  
   // in the first scan, new space needed for results
   if (pMeterQueryInfo->numOfPages == 0) {
-    pData = addDataPageForMeterQueryInfo(pMeterQueryInfo, pSupporter);
+    pData = addDataPageForMeterQueryInfo(pQuery, pMeterQueryInfo, pSupporter);
   } else {
     int32_t lastPageId = pMeterQueryInfo->pageList[pMeterQueryInfo->numOfPages - 1];
     pData = getFilePage(pSupporter, lastPageId);
 
     if (pData->numOfElems >= pRuntimeEnv->numOfRowsPerPage) {
-      pData = addDataPageForMeterQueryInfo(pMeterQueryInfo, pSupporter);
-      assert(pData->numOfElems == 0);  // number of elements must be 0 for new allocated buffer
+      pData = addDataPageForMeterQueryInfo(pRuntimeEnv->pQuery, pMeterQueryInfo, pSupporter);
+      if (pData != NULL) {
+        assert(pData->numOfElems == 0);  // number of elements must be 0 for new allocated buffer
+      }
     }
   }
+  
+  if (pData == NULL) {
+    return -1;
+  }
 
   for (int32_t i = 0; i < pRuntimeEnv->pQuery->numOfOutputCols; ++i) {
     pRuntimeEnv->pCtx[i].aOutputBuf = getOutputResPos(pRuntimeEnv, pData, pData->numOfElems, i);
     pRuntimeEnv->pCtx[i].resultInfo = &pMeterQueryInfo->resultInfo[i];
   }
+  
+  return TSDB_CODE_SUCCESS;
 }
 
-void setIntervalQueryExecutionContext(SMeterQuerySupportObj *pSupporter, int32_t meterIdx,
+int32_t setIntervalQueryExecutionContext(SMeterQuerySupportObj *pSupporter, int32_t meterIdx,
                                       SMeterQueryInfo *pMeterQueryInfo) {
   SQueryRuntimeEnv *pRuntimeEnv = &pSupporter->runtimeEnv;
-  SQuery *          pQuery = pRuntimeEnv->pQuery;
 
   if (IS_MASTER_SCAN(pRuntimeEnv)) {
-    setOutputBufferForIntervalQuery(pSupporter, pMeterQueryInfo);
+    if (setOutputBufferForIntervalQuery(pSupporter, pMeterQueryInfo) != TSDB_CODE_SUCCESS) {
+      // not enough disk space or memory buffer for intermediate results
+      return -1;
+    }
 
     if (pMeterQueryInfo->lastResRows == 0) {
       initCtxOutputBuf(pRuntimeEnv);
     }
 
-    // reset the number of iterated elements, once this function is called. since the pCtx for different
-    for (int32_t j = 0; j < pQuery->numOfOutputCols; ++j) {
-      //      pRuntimeEnv->pCtx[j].numOfIteratedElems = 0;
-    }
-
   } else {
     if (pMeterQueryInfo->reverseFillRes) {
       setCtxOutputPointerForSupplementScan(pSupporter, pMeterQueryInfo);
@@ -6249,7 +6311,9 @@ void setIntervalQueryExecutionContext(SMeterQuerySupportObj *pSupporter, int32_t
        *
        * If the master scan does not produce any results, new spaces needed to be allocated during supplement scan
        */
-      setOutputBufferForIntervalQuery(pSupporter, pMeterQueryInfo);
+      if (setOutputBufferForIntervalQuery(pSupporter, pMeterQueryInfo) != TSDB_CODE_SUCCESS) {
+        return -1;
+      }
     }
   }
 
@@ -6659,14 +6723,14 @@ static void validateResultBuf(SMeterQuerySupportObj *pSupporter, SMeterQueryInfo
   }
 }
 
-void saveResult(SMeterQuerySupportObj *pSupporter, SMeterQueryInfo *pMeterQueryInfo, int32_t numOfResult) {
+int32_t saveResult(SMeterQuerySupportObj *pSupporter, SMeterQueryInfo *pMeterQueryInfo, int32_t numOfResult) {
   SQueryRuntimeEnv *pRuntimeEnv = &pSupporter->runtimeEnv;
   SQuery *          pQuery = pRuntimeEnv->pQuery;
 
   // no results generated, do nothing for master scan
   if (numOfResult <= 0) {
     if (IS_MASTER_SCAN(pRuntimeEnv)) {
-      return;
+      return TSDB_CODE_SUCCESS;
     } else {
       /*
        * There is a case that no result generated during the the supplement scan, and during the main
@@ -6691,7 +6755,7 @@ void saveResult(SMeterQuerySupportObj *pSupporter, SMeterQueryInfo *pMeterQueryI
         setCtxOutputPointerForSupplementScan(pSupporter, pMeterQueryInfo);
       }
 
-      return;
+      return TSDB_CODE_SUCCESS;
     }
   }
 
@@ -6720,7 +6784,9 @@ void saveResult(SMeterQuerySupportObj *pSupporter, SMeterQueryInfo *pMeterQueryI
     pMeterQueryInfo->numOfRes += numOfResult;
     assert(pData->numOfElems <= pRuntimeEnv->numOfRowsPerPage);
 
-    setOutputBufferForIntervalQuery(pSupporter, pMeterQueryInfo);
+    if (setOutputBufferForIntervalQuery(pSupporter, pMeterQueryInfo) != TSDB_CODE_SUCCESS) {
+      return -1;
+    }
 
     for (int32_t i = 0; i < pQuery->numOfOutputCols; ++i) {
       resetResultInfo(&pMeterQueryInfo->resultInfo[i]);
@@ -6743,6 +6809,8 @@ void saveResult(SMeterQuerySupportObj *pSupporter, SMeterQueryInfo *pMeterQueryI
         tColModelDisplay(cm, outputPage->data, outputPage->numOfElems, pRuntimeEnv->numOfRowsPerPage);
 #endif
   }
+  
+  return TSDB_CODE_SUCCESS;
 }
 
 static int32_t getSubsetNumber(SMeterQuerySupportObj *pSupporter) {
diff --git a/src/system/detail/src/vnodeQueryProcess.c b/src/system/detail/src/vnodeQueryProcess.c
index dea865e5cdf2ba833b5f49c96fb98033e752e550..cec76d1cba836d3161d32240b1ccf3af91230fa5 100644
--- a/src/system/detail/src/vnodeQueryProcess.c
+++ b/src/system/detail/src/vnodeQueryProcess.c
@@ -157,7 +157,11 @@ static SMeterDataInfo *queryOnMultiDataCache(SQInfo *pQInfo, SMeterDataInfo *pMe
 
         setExecutionContext(pSupporter, pSupporter->pResult, k, pMeterInfo[k].groupIdx, pMeterQueryInfo);
       } else {
-        setIntervalQueryExecutionContext(pSupporter, k, pMeterQueryInfo);
+        int32_t ret = setIntervalQueryExecutionContext(pSupporter, k, pMeterQueryInfo);
+        if (ret != TSDB_CODE_SUCCESS) {
+          pQInfo->killed = 1;
+          return NULL;
+        }
       }
 
       qTrace("QInfo:%p vid:%d sid:%d id:%s, query in cache, qrange:%lld-%lld, lastKey:%lld", pQInfo, pMeterObj->vnode,
@@ -306,7 +310,7 @@ static SMeterDataInfo *queryOnMultiDataFiles(SQInfo *pQInfo, SMeterDataInfo *pMe
     if (pReqMeterDataInfo == NULL) {
       dError("QInfo:%p failed to allocate memory to perform query processing, abort", pQInfo);
 
-      pQInfo->code = TSDB_CODE_SERV_OUT_OF_MEMORY;
+      pQInfo->code = -TSDB_CODE_SERV_OUT_OF_MEMORY;
       pQInfo->killed = 1;
       return NULL;
     }
@@ -338,7 +342,7 @@ static SMeterDataInfo *queryOnMultiDataFiles(SQInfo *pQInfo, SMeterDataInfo *pMe
       dError("QInfo:%p failed to allocate memory to perform query processing, abort", pQInfo);
       tfree(pReqMeterDataInfo);
 
-      pQInfo->code = TSDB_CODE_SERV_OUT_OF_MEMORY;
+      pQInfo->code = -TSDB_CODE_SERV_OUT_OF_MEMORY;
       pQInfo->killed = 1;
       return NULL;
     }
@@ -393,7 +397,12 @@ static SMeterDataInfo *queryOnMultiDataFiles(SQInfo *pQInfo, SMeterDataInfo *pMe
         setExecutionContext(pSupporter, pSupporter->pResult, pOneMeterDataInfo->meterOrderIdx,
                             pOneMeterDataInfo->groupIdx, pMeterQueryInfo);
       } else {  // interval query
-        setIntervalQueryExecutionContext(pSupporter, pOneMeterDataInfo->meterOrderIdx, pMeterQueryInfo);
+        int32_t ret = setIntervalQueryExecutionContext(pSupporter, pOneMeterDataInfo->meterOrderIdx, pMeterQueryInfo);
+        if (ret != TSDB_CODE_SUCCESS) {
+          tfree(pReqMeterDataInfo);  // error code has been set
+          pQInfo->killed = 1;
+          return NULL;
+        }
       }
 
       SCompBlock *pBlock = pInfoEx->pBlock.compBlock;
@@ -900,7 +909,12 @@ static void vnodeMultiMeterQueryProcessor(SQInfo *pQInfo) {
   dTrace("QInfo:%p main scan completed, elapsed time: %lldms, supplementary scan start, order:%d", pQInfo, et - st,
          pQuery->order.order ^ 1);
 
-  doCloseAllOpenedResults(pSupporter);
+  // failed to save all intermediate results into disk, abort further query processing
+  if (doCloseAllOpenedResults(pSupporter) != TSDB_CODE_SUCCESS) {
+    dError("QInfo:%p failed to save intermediate results, abort further query processing", pQInfo);
+    return;
+  }
+  
   doMultiMeterSupplementaryScan(pQInfo);
 
   if (isQueryKilled(pQuery)) {
@@ -911,12 +925,13 @@ static void vnodeMultiMeterQueryProcessor(SQInfo *pQInfo) {
   if (pQuery->nAggTimeInterval > 0) {
     assert(pSupporter->subgroupIdx == 0 && pSupporter->numOfGroupResultPages == 0);
 
-    mergeMetersResultToOneGroups(pSupporter);
-    copyResToQueryResultBuf(pSupporter, pQuery);
-
+    if (mergeMetersResultToOneGroups(pSupporter) == TSDB_CODE_SUCCESS) {
+      copyResToQueryResultBuf(pSupporter, pQuery);
+      
 #ifdef _DEBUG_VIEW
-    displayInterResult(pQuery->sdata, pQuery, pQuery->sdata[0]->len);
+      displayInterResult(pQuery->sdata, pQuery, pQuery->sdata[0]->len);
 #endif
+    }
   } else {  // not a interval query
     copyFromGroupBuf(pQInfo, pSupporter->pResult);
   }
diff --git a/src/system/detail/src/vnodeRead.c b/src/system/detail/src/vnodeRead.c
index 81e4f6e370ae0a8591ec7c63fcdabc53732df2ec..d6f0796121ddc180325ad4cdf8e9012bd35cebfa 100644
--- a/src/system/detail/src/vnodeRead.c
+++ b/src/system/detail/src/vnodeRead.c
@@ -824,11 +824,11 @@ int vnodeRetrieveQueryInfo(void *handle, int *numOfRows, int *rowSize, int16_t *
   }
 
   if (pQInfo->killed) {
-    dTrace("QInfo:%p it is already killed, %p, code:%d", pQInfo, pQuery, pQInfo->code);
+    dTrace("QInfo:%p query is killed, %p, code:%d", pQInfo, pQuery, pQInfo->code);
     if (pQInfo->code == TSDB_CODE_SUCCESS) {
       return TSDB_CODE_QUERY_CANCELLED;
     } else { // in case of not TSDB_CODE_SUCCESS, return the code to client
-      return pQInfo->code;
+      return abs(pQInfo->code);
     }
   }
 
@@ -837,8 +837,13 @@ int vnodeRetrieveQueryInfo(void *handle, int *numOfRows, int *rowSize, int16_t *
   *rowSize = pQuery->rowSize;
 
   *timePrec = vnodeList[pQInfo->pObj->vnode].cfg.precision;
-
-  if (pQInfo->code < 0) return -pQInfo->code;
+  
+  dTrace("QInfo:%p, retrieve data info completed, precision:%d, rowsize:%d, rows:%d, code:%d", pQInfo, *timePrec,
+      *rowSize, *numOfRows, pQInfo->code);
+  
+  if (pQInfo->code < 0) {  // less than 0 means there are error existed.
+    return -pQInfo->code;
+  }
 
   return TSDB_CODE_SUCCESS;
 }
diff --git a/src/system/detail/src/vnodeShell.c b/src/system/detail/src/vnodeShell.c
index f4b3cdbbe72a7adc2321987335f861ce9b2034c2..ba9e682f8b775e082542ebe834ccbd2f8ab1a52b 100644
--- a/src/system/detail/src/vnodeShell.c
+++ b/src/system/detail/src/vnodeShell.c
@@ -606,7 +606,7 @@ int vnodeProcessShellSubmitRequest(char *pMsg, int msgLen, SShellObj *pObj) {
 
   if (tsAvailDataDirGB < tsMinimalDataDirGB) {
     dError("server disk space remain %.3f GB, need at least %.3f GB, stop writing", tsAvailDataDirGB, tsMinimalDataDirGB);
-    code = TSDB_CODE_SERVER_NO_SPACE;
+    code = TSDB_CODE_SERV_NO_DISKSPACE;
     goto _submit_over;
   }
 
diff --git a/src/util/src/tglobalcfg.c b/src/util/src/tglobalcfg.c
index cef11d30cba8fe4488a0cc6adcad7b4143f4fe8d..80f76a3d25be300866f4f90c0ebb444242402185 100644
--- a/src/util/src/tglobalcfg.c
+++ b/src/util/src/tglobalcfg.c
@@ -124,6 +124,7 @@ int tsMgmtEqualVnodeNum = 0;
 int tsEnableHttpModule = 1;
 int tsEnableMonitorModule = 1;
 int tsRestRowLimit = 10240;
+int tsMaxSQLStringLen = TSDB_MAX_SQL_LEN;
 
 /*
  * denote if the server needs to compress response message at the application layer to client, including query rsp,
@@ -653,7 +654,11 @@ static void doInitGlobalConfig() {
   tsInitConfigOption(cfg++, "compressMsgSize", &tsCompressMsgSize, TSDB_CFG_VTYPE_INT,
                      TSDB_CFG_CTYPE_B_CONFIG | TSDB_CFG_CTYPE_B_CLIENT | TSDB_CFG_CTYPE_B_SHOW,
                      -1, 10000000, 0, TSDB_CFG_UTYPE_NONE);
-
+  
+  tsInitConfigOption(cfg++, "maxSQLLength", &tsMaxSQLStringLen, TSDB_CFG_VTYPE_INT,
+                     TSDB_CFG_CTYPE_B_CONFIG | TSDB_CFG_CTYPE_B_CLIENT | TSDB_CFG_CTYPE_B_SHOW,
+                     TSDB_MAX_SQL_LEN, TSDB_MAX_ALLOWED_SQL_LEN, 0, TSDB_CFG_UTYPE_BYTE);
+  
   // locale & charset
   tsInitConfigOption(cfg++, "timezone", tsTimezone, TSDB_CFG_VTYPE_STRING,
                      TSDB_CFG_CTYPE_B_CONFIG | TSDB_CFG_CTYPE_B_CLIENT,
diff --git a/src/util/src/tstrbuild.c b/src/util/src/tstrbuild.c
index 6fb970bd6e3de13d6119089759fcf030d6c618fc..691435749317f637b28140a30808f2896c8c04f6 100644
--- a/src/util/src/tstrbuild.c
+++ b/src/util/src/tstrbuild.c
@@ -13,10 +13,8 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include "os.h"
 #include "tstrbuild.h"
-#include <stdlib.h>
-#include <string.h>
-#include <stdio.h>
 
 void taosStringBuilderEnsureCapacity(SStringBuilder* sb, size_t size) {
   size += sb->pos;