diff --git a/documentation20/webdocs/markdowndocs/architecture-ch.md b/documentation20/webdocs/markdowndocs/architecture-ch.md
index 7ab4b5d096b4676b205fa57175889f780df2cb45..a279875649503c64861f7b42b64741967f75aa69 100644
--- a/documentation20/webdocs/markdowndocs/architecture-ch.md
+++ b/documentation20/webdocs/markdowndocs/architecture-ch.md
@@ -162,7 +162,7 @@ Master Vnode遵循下面的写入流程：
 
 <center> 图 3 TDengine Master写入流程  </center>
 1. Master vnode收到应用的数据插入请求，验证OK，进入下一步；
-2. 如果系统配置参数walLevel打开（设置为2），vnode将把该请求的原始数据包写入数据库日志文件WAL，以保证TDengine能够在断电等因素导致的服务重启时从数据库日志文件中恢复数据，避免数据的丢失；
+2. 如果系统配置参数walLevel大于0，vnode将把该请求的原始数据包写入数据库日志文件WAL。如果walLevel设置为2，而且fsync设置为0，TDengine还将WAL数据立即落盘，以保证即使宕机，也能从数据库日志文件中恢复数据，避免数据的丢失；
 3. 如果有多个副本，vnode将把数据包转发给同一虚拟节点组内slave vnodes, 该转发包带有数据的版本号(version)；
 4. 写入内存，并加记录加入到skip list；
 5. Master vnode返回确认信息给应用，表示写入成功。
@@ -174,7 +174,7 @@ Master Vnode遵循下面的写入流程：
 
 <center> 图 4 TDengine Slave写入流程  </center>
 1. Slave vnode收到Master vnode转发了的数据插入请求。
-2. 如果系统配置参数walLevl设置为2，vnode将把该请求的原始数据包写入日志(WAL)；
+2. 如果系统配置参数walLevel大于0，vnode将把该请求的原始数据包写入数据库日志文件WAL。如果walLevel设置为2，而且fsync设置为0，TDengine还将WAL数据立即落盘，以保证即使宕机，也能从数据库日志文件中恢复数据，避免数据的丢失；
 3. 写入内存，更新内存中的skip list。
 
 与Master vnode相比，slave vnode不存在转发环节，也不存在回复确认环节，少了两步。但写内存与WAL是完全一样的。
diff --git a/src/client/inc/tsclient.h b/src/client/inc/tsclient.h
index 4485e31bcdebb7df9998a99c665b1fa7774a2afd..78544b9b99143fa988304fa04bc104786e6866bf 100644
--- a/src/client/inc/tsclient.h
+++ b/src/client/inc/tsclient.h
@@ -399,7 +399,7 @@ int tsParseSql(SSqlObj *pSql, bool initial);
 void tscProcessMsgFromServer(SRpcMsg *rpcMsg, SRpcEpSet *pEpSet);
 int  tscProcessSql(SSqlObj *pSql);
 
-int  tscRenewTableMeta(SSqlObj *pSql, char *tableId);
+int  tscRenewTableMeta(SSqlObj *pSql, int32_t tableIndex);
 void tscQueueAsyncRes(SSqlObj *pSql);
 
 void tscQueueAsyncError(void(*fp), void *param, int32_t code);
@@ -414,7 +414,7 @@ void    tscRestoreSQLFuncForSTableQuery(SQueryInfo *pQueryInfo);
 int32_t tscCreateResPointerInfo(SSqlRes *pRes, SQueryInfo *pQueryInfo);
 void    tscDestroyResPointerInfo(SSqlRes *pRes);
 
-void tscResetSqlCmdObj(SSqlCmd *pCmd);
+void tscResetSqlCmdObj(SSqlCmd *pCmd, bool removeFromCache);
 
 /**
  * free query result of the sql object
@@ -456,6 +456,7 @@ bool tscResultsetFetchCompleted(TAOS_RES *result);
 char *tscGetErrorMsgPayload(SSqlCmd *pCmd);
 
 int32_t tscInvalidSQLErrMsg(char *msg, const char *additionalInfo, const char *sql);
+int32_t tscSQLSyntaxErrMsg(char* msg, const char* additionalInfo,  const char* sql);
 
 int32_t tscToSQLCmd(SSqlObj *pSql, struct SSqlInfo *pInfo);
 
diff --git a/src/client/src/tscAsync.c b/src/client/src/tscAsync.c
index 41aa1221601f8b1b2ef65b09539025d417812adb..650f101645e68f3b84ccbd25c82bf6696c041808 100644
--- a/src/client/src/tscAsync.c
+++ b/src/client/src/tscAsync.c
@@ -468,7 +468,7 @@ void tscTableMetaCallBack(void *param, TAOS_RES *res, int code) {
         if (pCmd->command == TSDB_SQL_INSERT || pCmd->command == TSDB_SQL_SELECT) {
           tscDebug("%p redo parse sql string and proceed", pSql);
           pCmd->parseFinished = false;
-          tscResetSqlCmdObj(pCmd);
+          tscResetSqlCmdObj(pCmd, false);
 
           code = tsParseSql(pSql, true);
 
diff --git a/src/client/src/tscParseInsert.c b/src/client/src/tscParseInsert.c
index 47bfe0fcdcc0e0331e36e146627feea18bd31b2c..7f8fd7f4feaad472db5e06744c7cea742e22c9c7 100644
--- a/src/client/src/tscParseInsert.c
+++ b/src/client/src/tscParseInsert.c
@@ -180,7 +180,7 @@ int32_t tsParseOneColumnData(SSchema *pSchema, SStrToken *pToken, char *payload,
         } else if (strncasecmp(TSDB_DATA_NULL_STR_L, pToken->z, pToken->n) == 0) {
           *(uint8_t *)payload = TSDB_DATA_BOOL_NULL;
         } else {
-          return tscInvalidSQLErrMsg(msg, "invalid bool data", pToken->z);
+          return tscSQLSyntaxErrMsg(msg, "invalid bool data", pToken->z);
         }
       } else if (pToken->type == TK_INTEGER) {
         iv = strtoll(pToken->z, NULL, 10);
@@ -439,8 +439,8 @@ int tsParseOneRowData(char **str, STableDataBlocks *pDataBlocks, SSchema schema[
     int16_t type = sToken.type;
     if ((type != TK_NOW && type != TK_INTEGER && type != TK_STRING && type != TK_FLOAT && type != TK_BOOL &&
          type != TK_NULL && type != TK_HEX && type != TK_OCT && type != TK_BIN) || (sToken.n == 0) || (type == TK_RP)) {
-      tscInvalidSQLErrMsg(error, "invalid data or symbol", sToken.z);
-      *code = TSDB_CODE_TSC_INVALID_SQL;
+      tscSQLSyntaxErrMsg(error, "invalid data or symbol", sToken.z);
+      *code = TSDB_CODE_TSC_SQL_SYNTAX_ERROR;
       return -1;
     }
 
@@ -472,7 +472,7 @@ int tsParseOneRowData(char **str, STableDataBlocks *pDataBlocks, SSchema schema[
     bool    isPrimaryKey = (colIndex == PRIMARYKEY_TIMESTAMP_COL_INDEX);
     int32_t ret = tsParseOneColumnData(pSchema, &sToken, start, error, str, isPrimaryKey, timePrec);
     if (ret != TSDB_CODE_SUCCESS) {
-      *code = TSDB_CODE_TSC_INVALID_SQL;
+      *code = TSDB_CODE_TSC_SQL_SYNTAX_ERROR;
       return -1;  // NOTE: here 0 mean error!
     }
 
@@ -568,8 +568,8 @@ int tsParseValues(char **str, STableDataBlocks *pDataBlock, STableMeta *pTableMe
     sToken = tStrGetToken(*str, &index, false, 0, NULL);
     *str += index;
     if (sToken.n == 0 || sToken.type != TK_RP) {
-      tscInvalidSQLErrMsg(error, ") expected", *str);
-      *code = TSDB_CODE_TSC_INVALID_SQL;
+      tscSQLSyntaxErrMsg(error, ") expected", *str);
+      *code = TSDB_CODE_TSC_SQL_SYNTAX_ERROR;
       return -1;
     }
 
@@ -578,7 +578,7 @@ int tsParseValues(char **str, STableDataBlocks *pDataBlock, STableMeta *pTableMe
 
   if (numOfRows <= 0) {
     strcpy(error, "no any data points");
-    *code = TSDB_CODE_TSC_INVALID_SQL;
+    *code = TSDB_CODE_TSC_SQL_SYNTAX_ERROR;
     return -1;
   } else {
     return numOfRows;
@@ -943,7 +943,7 @@ static int32_t tscCheckIfCreateTable(char **sqlstr, SSqlObj *pSql) {
     sToken = tStrGetToken(sql, &index, false, 0, NULL);
     sql += index;
     if (sToken.n == 0 || sToken.type != TK_RP) {
-      return tscInvalidSQLErrMsg(pCmd->payload, ") expected", sToken.z);
+      return tscSQLSyntaxErrMsg(pCmd->payload, ") expected", sToken.z);
     }
 
     pCmd->payloadLen = sizeof(pTag->name) + sizeof(pTag->dataLen) + pTag->dataLen;
@@ -1327,18 +1327,40 @@ int tsParseSql(SSqlObj *pSql, bool initial) {
       pSql->fetchFp = pSql->fp;
       pSql->fp = (void(*)())tscHandleMultivnodeInsert;
     }
-    
+
     if (initial && ((ret = tsInsertInitialCheck(pSql)) != TSDB_CODE_SUCCESS)) {
       return ret;
     }
-    
+
+    // make a backup as tsParseInsertSql may modify the string
+    char* sqlstr = strdup(pSql->sqlstr);
     ret = tsParseInsertSql(pSql);
+    if (sqlstr == NULL || pSql->retry >= 1 || ret != TSDB_CODE_TSC_INVALID_SQL) {
+      free(sqlstr);
+    } else {
+      tscResetSqlCmdObj(pCmd, true);
+      free(pSql->sqlstr);
+      pSql->sqlstr = sqlstr;
+      pSql->retry++;
+      if ((ret = tsInsertInitialCheck(pSql)) == TSDB_CODE_SUCCESS) {
+        ret = tsParseInsertSql(pSql);
+      }
+    }
   } else {
     SSqlInfo SQLInfo = qSQLParse(pSql->sqlstr);
     ret = tscToSQLCmd(pSql, &SQLInfo);
+    if (ret == TSDB_CODE_TSC_INVALID_SQL && pSql->retry == 0 && SQLInfo.type == TSDB_SQL_NULL) {
+      tscResetSqlCmdObj(pCmd, true);
+      pSql->retry++;
+      ret = tscToSQLCmd(pSql, &SQLInfo);
+    }
     SQLInfoDestroy(&SQLInfo);
   }
 
+  if (ret == TSDB_CODE_SUCCESS) {
+    pSql->retry = 0;
+  }
+
   /*
    * the pRes->code may be modified or released by another thread in tscTableMetaCallBack function,
    * so do NOT use pRes->code to determine if the getTableMeta function
diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 05f32d0ab89eaff63d372be1b312b888d49513b1..de608961c2a24f246148d4ca2af90a20a66c91fd 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -190,7 +190,7 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
 
   int32_t code = TSDB_CODE_SUCCESS;
   if (!pInfo->valid) {
-    return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), pInfo->pzErrMsg);
+    return tscSQLSyntaxErrMsg(tscGetErrorMsgPayload(pCmd), NULL, pInfo->pzErrMsg);
   }
 
   SQueryInfo* pQueryInfo = tscGetQueryInfoDetailSafely(pCmd, pCmd->clauseIndex);
diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index 1f042b59d6ae09edf8eddd0a450fe1becd6be033..16e3458e133980bf5e85ea85c25da893c2b55929 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -276,8 +276,6 @@ void tscProcessMsgFromServer(SRpcMsg *rpcMsg, SRpcEpSet *pEpSet) {
     }
   }
 
-  STableMetaInfo *pTableMetaInfo = tscGetTableMetaInfoFromCmd(pCmd, pCmd->clauseIndex, 0);
-
   int32_t cmd = pCmd->command;
   if ((cmd == TSDB_SQL_SELECT || cmd == TSDB_SQL_FETCH || cmd == TSDB_SQL_INSERT || cmd == TSDB_SQL_UPDATE_TAGS_VAL) &&
       (rpcMsg->code == TSDB_CODE_TDB_INVALID_TABLE_ID ||
@@ -302,7 +300,7 @@ void tscProcessMsgFromServer(SRpcMsg *rpcMsg, SRpcEpSet *pEpSet) {
         taosMsleep(duration);
       }
 
-      rpcMsg->code = tscRenewTableMeta(pSql, pTableMetaInfo->name);
+      rpcMsg->code = tscRenewTableMeta(pSql, 0);
 
       // if there is an error occurring, proceed to the following error handling procedure.
       if (rpcMsg->code == TSDB_CODE_TSC_ACTION_IN_PROGRESS) {
@@ -2202,14 +2200,14 @@ int tscGetMeterMetaEx(SSqlObj *pSql, STableMetaInfo *pTableMetaInfo, bool create
 /**
  * retrieve table meta from mnode, and update the local table meta cache.
  * @param pSql          sql object
- * @param tableId       table full name
+ * @param tableIndex    table index
  * @return              status code
  */
-int tscRenewTableMeta(SSqlObj *pSql, char *tableId) {
+int tscRenewTableMeta(SSqlObj *pSql, int32_t tableIndex) {
   SSqlCmd *pCmd = &pSql->cmd;
 
   SQueryInfo *    pQueryInfo = tscGetQueryInfoDetail(pCmd, 0);
-  STableMetaInfo *pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
+  STableMetaInfo *pTableMetaInfo = tscGetMetaInfo(pQueryInfo, tableIndex);
 
   STableMeta* pTableMeta = pTableMetaInfo->pTableMeta;
   if (pTableMetaInfo->pTableMeta) {
diff --git a/src/client/src/tscSql.c b/src/client/src/tscSql.c
index f63923e046f889cf2f63c93fce37dacf0c858d09..9fa4db999f1257e09a40bfd9720f77e9da94ec3a 100644
--- a/src/client/src/tscSql.c
+++ b/src/client/src/tscSql.c
@@ -597,11 +597,12 @@ int taos_errno(TAOS_RES *tres) {
 }
 
 /*
- * In case of invalid sql error, additional information is attached to explain
+ * In case of invalid sql/sql syntax error, additional information is attached to explain
  * why the sql is invalid
  */
 static bool hasAdditionalErrorInfo(int32_t code, SSqlCmd *pCmd) {
-  if (code != TSDB_CODE_TSC_INVALID_SQL) {
+  if (code != TSDB_CODE_TSC_INVALID_SQL
+      && code != TSDB_CODE_TSC_SQL_SYNTAX_ERROR) {
     return false;
   }
 
@@ -609,9 +610,11 @@ static bool hasAdditionalErrorInfo(int32_t code, SSqlCmd *pCmd) {
 
   char *z = NULL;
   if (len > 0) {
-    z = strstr(pCmd->payload, "invalid SQL");
+      z = strstr(pCmd->payload, "invalid SQL");
+      if (z == NULL) {
+        z = strstr(pCmd->payload, "syntax error");
+      }
   }
-
   return z != NULL;
 }
 
@@ -817,7 +820,7 @@ int taos_validate_sql(TAOS *taos, const char *sql) {
 
 static int tscParseTblNameList(SSqlObj *pSql, const char *tblNameList, int32_t tblListLen) {
   // must before clean the sqlcmd object
-  tscResetSqlCmdObj(&pSql->cmd);
+  tscResetSqlCmdObj(&pSql->cmd, false);
 
   SSqlCmd *pCmd = &pSql->cmd;
 
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index 6aa620eed215487b146515ad94e082b734b40f07..b45d40f49cdb30a7ff88f488e9a9b7354ce89b81 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -33,7 +33,7 @@
 static void freeQueryInfoImpl(SQueryInfo* pQueryInfo);
 static void clearAllTableMetaInfo(SQueryInfo* pQueryInfo, const char* address, bool removeFromCache);
 
-  SCond* tsGetSTableQueryCond(STagCond* pTagCond, uint64_t uid) {
+SCond* tsGetSTableQueryCond(STagCond* pTagCond, uint64_t uid) {
   if (pTagCond->pCond == NULL) {
     return NULL;
   }
@@ -294,7 +294,7 @@ void tscDestroyResPointerInfo(SSqlRes* pRes) {
   pRes->data = NULL;  // pRes->data points to the buffer of pRsp, no need to free
 }
 
-static void tscFreeQueryInfo(SSqlCmd* pCmd) {
+static void tscFreeQueryInfo(SSqlCmd* pCmd, bool removeFromCache) {
   if (pCmd == NULL || pCmd->numOfClause == 0) {
     return;
   }
@@ -304,7 +304,7 @@ static void tscFreeQueryInfo(SSqlCmd* pCmd) {
     SQueryInfo* pQueryInfo = tscGetQueryInfoDetail(pCmd, i);
     
     freeQueryInfoImpl(pQueryInfo);
-    clearAllTableMetaInfo(pQueryInfo, (const char*)addr, false);
+    clearAllTableMetaInfo(pQueryInfo, (const char*)addr, removeFromCache);
     taosTFree(pQueryInfo);
   }
   
@@ -312,7 +312,7 @@ static void tscFreeQueryInfo(SSqlCmd* pCmd) {
   taosTFree(pCmd->pQueryInfo);
 }
 
-void tscResetSqlCmdObj(SSqlCmd* pCmd) {
+void tscResetSqlCmdObj(SSqlCmd* pCmd, bool removeFromCache) {
   pCmd->command   = 0;
   pCmd->numOfCols = 0;
   pCmd->count     = 0;
@@ -326,7 +326,7 @@ void tscResetSqlCmdObj(SSqlCmd* pCmd) {
   
   pCmd->pDataBlocks = tscDestroyBlockArrayList(pCmd->pDataBlocks);
   
-  tscFreeQueryInfo(pCmd);
+  tscFreeQueryInfo(pCmd, removeFromCache);
 }
 
 void tscFreeSqlResult(SSqlObj* pSql) {
@@ -364,7 +364,7 @@ void tscPartiallyFreeSqlObj(SSqlObj* pSql) {
   taosTFree(pSql->pSubs);
   pSql->numOfSubs = 0;
   
-  tscResetSqlCmdObj(pCmd);
+  tscResetSqlCmdObj(pCmd, false);
 }
 
 void tscFreeSqlObj(SSqlObj* pSql) {
@@ -2040,10 +2040,37 @@ bool tscIsUpdateQuery(SSqlObj* pSql) {
   return ((pCmd->command >= TSDB_SQL_INSERT && pCmd->command <= TSDB_SQL_DROP_DNODE) || TSDB_SQL_USE_DB == pCmd->command);
 }
 
+int32_t tscSQLSyntaxErrMsg(char* msg, const char* additionalInfo,  const char* sql) {
+  const char* msgFormat1 = "syntax error near \'%s\'";
+  const char* msgFormat2 = "syntax error near \'%s\' (%s)";
+  const char* msgFormat3 = "%s";
+
+  const char* prefix = "syntax error"; 
+  const int32_t BACKWARD_CHAR_STEP = 0;
+
+  if (sql == NULL) {
+    assert(additionalInfo != NULL);
+    sprintf(msg, msgFormat1, additionalInfo);
+    return TSDB_CODE_TSC_SQL_SYNTAX_ERROR;
+  }
+
+  char buf[64] = {0};  // only extract part of sql string
+  strncpy(buf, (sql - BACKWARD_CHAR_STEP), tListLen(buf) - 1);
+
+  if (additionalInfo != NULL) {
+    sprintf(msg, msgFormat2, buf, additionalInfo);
+  } else {
+    const char* msgFormat = (0 == strncmp(sql, prefix, strlen(prefix))) ? msgFormat3 : msgFormat1; 
+    sprintf(msg, msgFormat, buf);
+  }
+
+  return TSDB_CODE_TSC_SQL_SYNTAX_ERROR;
+  
+}
 int32_t tscInvalidSQLErrMsg(char* msg, const char* additionalInfo, const char* sql) {
   const char* msgFormat1 = "invalid SQL: %s";
-  const char* msgFormat2 = "invalid SQL: syntax error near \"%s\" (%s)";
-  const char* msgFormat3 = "invalid SQL: syntax error near \"%s\"";
+  const char* msgFormat2 = "invalid SQL: \'%s\' (%s)";
+  const char* msgFormat3 = "invalid SQL: \'%s\'";
 
   const int32_t BACKWARD_CHAR_STEP = 0;
 
@@ -2269,4 +2296,4 @@ bool tscSetSqlOwner(SSqlObj* pSql) {
 void tscClearSqlOwner(SSqlObj* pSql) {
   assert(taosCheckPthreadValid(pSql->owner));
   atomic_store_64(&pSql->owner, 0);
-}
\ No newline at end of file
+}
diff --git a/src/inc/taoserror.h b/src/inc/taoserror.h
index 951c511022e5df1bf7e385cde526b177a12812ad..d8e5c8f1d748f09c67bd6827b9b9441a01b155c5 100644
--- a/src/inc/taoserror.h
+++ b/src/inc/taoserror.h
@@ -98,6 +98,7 @@ TAOS_DEFINE_ERROR(TSDB_CODE_TSC_ACTION_IN_PROGRESS,       0, 0x0212, "Action in
 TAOS_DEFINE_ERROR(TSDB_CODE_TSC_DISCONNECTED,             0, 0x0213, "Disconnected from service")
 TAOS_DEFINE_ERROR(TSDB_CODE_TSC_NO_WRITE_AUTH,            0, 0x0214, "No write permission")
 TAOS_DEFINE_ERROR(TSDB_CODE_TSC_CONN_KILLED,            0, 0x0215, "Connection killed")
+TAOS_DEFINE_ERROR(TSDB_CODE_TSC_SQL_SYNTAX_ERROR,            0, 0x0216, "Syntax errr in SQL")
 
 // mnode
 TAOS_DEFINE_ERROR(TSDB_CODE_MND_MSG_NOT_PROCESSED,        0, 0x0300, "Message not processed")
diff --git a/src/query/src/qPercentile.c b/src/query/src/qPercentile.c
index c6eb836c61f21dedcba0af780371551434e8085e..3e9b077d3011d8bfc918f3ff976a98e943998c55 100644
--- a/src/query/src/qPercentile.c
+++ b/src/query/src/qPercentile.c
@@ -38,9 +38,9 @@ static tFilePage *loadDataFromFilePage(tMemBucket *pMemBucket, int32_t slotIdx)
     SPageInfo* pgInfo = *(SPageInfo**) taosArrayGet(list, i);
 
     tFilePage* pg = getResBufPage(pMemBucket->pBuffer, pgInfo->pageId);
-    memcpy(buffer->data + offset, pg->data, pg->num * pMemBucket->bytes);
+    memcpy(buffer->data + offset, pg->data, (size_t)(pg->num * pMemBucket->bytes));
 
-    offset += pg->num * pMemBucket->bytes;
+    offset += (int32_t)(pg->num * pMemBucket->bytes);
   }
 
   qsort(buffer->data, pMemBucket->pSlots[slotIdx].info.size, pMemBucket->bytes, pMemBucket->comparFn);
@@ -142,7 +142,7 @@ int32_t tBucketBigIntHash(tMemBucket *pBucket, const void *value) {
       index = delta % pBucket->numOfSlots;
     } else {
       double slotSpan = (double)span / pBucket->numOfSlots;
-      index = (v - pBucket->range.i64MinVal) / slotSpan;
+      index = (int32_t)((v - pBucket->range.i64MinVal) / slotSpan);
       if (v == pBucket->range.i64MaxVal) {
         index -= 1;
       }
@@ -181,7 +181,7 @@ int32_t tBucketIntHash(tMemBucket *pBucket, const void *value) {
       index = (delta % pBucket->numOfSlots);
     } else {
       double slotSpan = (double)span / pBucket->numOfSlots;
-      index = (v - pBucket->range.iMinVal) / slotSpan;
+      index = (int32_t)((v - pBucket->range.iMinVal) / slotSpan);
       if (v == pBucket->range.iMaxVal) {
         index -= 1;
       }
@@ -211,7 +211,7 @@ int32_t tBucketDoubleHash(tMemBucket *pBucket, const void *value) {
       index = (delta % pBucket->numOfSlots);
     } else {
       double slotSpan = span / pBucket->numOfSlots;
-      index = (v - pBucket->range.dMinVal) / slotSpan;
+      index = (int32_t)((v - pBucket->range.dMinVal) / slotSpan);
       if (v == pBucket->range.dMaxVal) {
         index -= 1;
       }
@@ -392,7 +392,7 @@ void tMemBucketUpdateBoundingBox(MinMaxEntry *r, char *data, int32_t dataType) {
  */
 void tMemBucketPut(tMemBucket *pBucket, const void *data, size_t size) {
   assert(pBucket != NULL && data != NULL && size > 0);
-  pBucket->total += size;
+  pBucket->total += (int32_t)size;
 
   int32_t bytes = pBucket->bytes;
 
@@ -525,7 +525,7 @@ static double getIdenticalDataVal(tMemBucket* pMemBucket, int32_t slotIndex) {
     };
 
     case TSDB_DATA_TYPE_BIGINT: {
-      finalResult = pSlot->range.i64MinVal;
+      finalResult = (double)pSlot->range.i64MinVal;
       break;
     }
   }
diff --git a/tests/pytest/crash_gen.py b/tests/pytest/crash_gen.py
index 7588e03e17cd04afa615adc7274dd363421f8112..c0a8fd1f00ade2642b1f23f6f1ef3cc60dfe615b 100755
--- a/tests/pytest/crash_gen.py
+++ b/tests/pytest/crash_gen.py
@@ -693,7 +693,7 @@ class DbConnRest(DbConn):
     def __init__(self):
         super().__init__()
         self._type = self.TYPE_REST
-        self._url = "http://localhost:6020/rest/sql"  # fixed for now
+        self._url = "http://localhost:6041/rest/sql"  # fixed for now
         self._result = None
 
     def openByType(self):  # Open connection
@@ -1306,6 +1306,7 @@ class DbManager():
                     "Cannot establish DB connection, please re-run script without parameter, and follow the instructions.")
                 sys.exit(2)
             else:
+                print("Failed to connect to DB, errno = {}, msg: {}".format(Helper.convertErrno(err.errno), err.msg))
                 raise
         except BaseException:
             print("[=] Unexpected exception")
@@ -1910,10 +1911,19 @@ class TaskReadData(StateTransitionTask):
                 # 'twa(speed)', # TODO: this one REQUIRES a where statement, not reasonable
                 'sum(speed)', 
                 'stddev(speed)', 
+                # SELECTOR functions
                 'min(speed)', 
                 'max(speed)', 
                 'first(speed)', 
-                'last(speed)']) # TODO: add more from 'top'
+                'last(speed)',
+                # 'top(speed)', # TODO: not supported?
+                # 'bottom(speed)', # TODO: not supported?
+                # 'percentile(speed, 10)', # TODO: TD-1316
+                'last_row(speed)',
+                # Transformation Functions
+                # 'diff(speed)', # TODO: no supported?!
+                'spread(speed)'
+                ]) # TODO: add more from 'top'
             filterExpr = Dice.choice([ # TODO: add various kind of WHERE conditions
                 None
             ])
@@ -2350,7 +2360,7 @@ class ServiceManagerThread:
         self._thread2.start()
 
         # wait for service to start
-        for i in range(0, 10):
+        for i in range(0, 100):
             time.sleep(1.0)
             # self.procIpcBatch() # don't pump message during start up
             print("_zz_", end="", flush=True)
@@ -2358,7 +2368,7 @@ class ServiceManagerThread:
                 logger.info("[] TDengine service READY to process requests")
                 return  # now we've started
         # TODO: handle this better?
-        self.procIpcBatch(20, True) # display output before cronking out, trim to last 20 msgs, force output
+        self.procIpcBatch(100, True) # display output before cronking out, trim to last 20 msgs, force output
         raise RuntimeError("TDengine service did not start successfully")
 
     def stop(self):
@@ -2768,7 +2778,7 @@ class MainExec:
         try: 
             ret = self._clientMgr.run(self._svcMgr) # stop TAOS service inside
         except requests.exceptions.ConnectionError as err:
-            logger.warning("Failed to open REST connection to DB")
+            logger.warning("Failed to open REST connection to DB: {}".format(err.getMessage()))
             # don't raise
         return ret
 
diff --git a/tests/script/general/http/restful_full.sim b/tests/script/general/http/restful_full.sim
index 88e7dece4c939b6a935634cce40e41aff4512bb2..b7f98e49e06e6efa5f6adca372a2917c6e91ca21 100644
--- a/tests/script/general/http/restful_full.sim
+++ b/tests/script/general/http/restful_full.sim
@@ -119,7 +119,7 @@ endi
 
 system_content curl -H 'Authorization: Taosd /KfeAzX/f9na8qdtNZmtONryp201ma04bEl8LcvLUd7a8qdtNZmtONryp201ma04'  -d '  used1' 127.0.0.1:7111/rest/sql
 print 17-> $system_content
-if $system_content != @{"status":"error","code":512,"desc":"invalid SQL: invalid SQL: syntax error near 'used1'"}@ then
+if $system_content != @{"status":"error","code":534,"desc":"Syntax errr in SQL"}@ then
   return -1
 endi
 
@@ -230,4 +230,4 @@ if $system_content != @{"status":"succ","head":["ts","speed"],"data":[["2017-12-
   return -1
 endi
 
-system sh/exec.sh -n dnode1 -s stop -x SIGINT
\ No newline at end of file
+system sh/exec.sh -n dnode1 -s stop -x SIGINT