diff --git a/src/client/src/tscAsync.c b/src/client/src/tscAsync.c
index ef90b184a0183e22350c708057c54256c58c9523..660db08030879339a276a71019ca56f68ad34236 100644
--- a/src/client/src/tscAsync.c
+++ b/src/client/src/tscAsync.c
@@ -526,8 +526,7 @@ void tscMeterMetaCallBack(void *param, TAOS_RES *res, int code) {
     /*
      * NOTE:
      * transfer the sql function for metric query before get meter/metric meta,
-     * since in callback functions,
-     * only tscProcessSql(pStream->pSql) is executed!
+     * since in callback functions, only tscProcessSql(pStream->pSql) is executed!
      */
     tscTansformSQLFunctionForMetricQuery(&pSql->cmd);
     tscIncStreamExecutionCount(pSql->pStream);
diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 9bd1f123e1f8ad2487cc2a172d9a90e910e8a796..d5935f51c2dcaf933f2327db13f43882e8ed2f0d 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -1586,7 +1586,7 @@ static int32_t setExprInfoForFunctions(SSqlCmd* pCmd, SSchema* pSchema, int32_t
   int16_t type = 0;
   int16_t bytes = 0;
 
-  char columnName[TSDB_COL_NAME_LEN + 1] = {0};
+  char columnName[TSDB_COL_NAME_LEN] = {0};
   char msg1[] = "not support column types";
 
   if (functionID == TSDB_FUNC_SPREAD) {
@@ -3570,20 +3570,27 @@ int32_t setAlterTableInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
     pCmd->numOfCols = 1;  // only one column
 
   } else if (pInfo->sqlType == ALTER_TABLE_TAGS_CHG) {
+    char msg1[] = "tag name too long";
+    char msg2[] = "invalid tag name";
+
     pCmd->count = TSDB_ALTER_TABLE_CHANGE_TAG_COLUMN;
     tVariantList* pVarList = pAlterSQL->varList;
     if (pVarList->nExpr > 2) {
       return TSDB_CODE_INVALID_SQL;
     }
 
-    if (pVarList->a[0].pVar.nLen > TSDB_COL_NAME_LEN || pVarList->a[1].pVar.nLen > TSDB_COL_NAME_LEN) {
-      char msg[] = "tag name too long";
-      setErrMsg(pCmd, msg, tListLen(msg));
+    tVariantListItem* pSrcItem = &pAlterSQL->varList->a[0];
+    tVariantListItem* pDstItem = &pAlterSQL->varList->a[1];
+
+    if (pSrcItem->pVar.nLen >= TSDB_COL_NAME_LEN || pDstItem->pVar.nLen >= TSDB_COL_NAME_LEN) {
+      setErrMsg(pCmd, msg1, tListLen(msg1));
       return TSDB_CODE_INVALID_SQL;
     }
 
-    tVariantListItem* pSrcItem = &pAlterSQL->varList->a[0];
-    tVariantListItem* pDstItem = &pAlterSQL->varList->a[1];
+    if (pSrcItem->pVar.nType != TSDB_DATA_TYPE_BINARY || pDstItem->pVar.nType != TSDB_DATA_TYPE_BINARY) {
+      setErrMsg(pCmd, msg2, tListLen(msg2));
+      return TSDB_CODE_INVALID_SQL;
+    }
 
     bool srcFound = false;
     bool dstFound = false;
@@ -3592,11 +3599,12 @@ int32_t setAlterTableInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
       char*   tagName = pSchema[tagIdx].name;
 
       size_t nameLen = strlen(tagName);
-      if ((!srcFound) && strncasecmp(tagName, pSrcItem->pVar.pz, nameLen) == 0) {
+      if ((!srcFound) && (strncasecmp(tagName, pSrcItem->pVar.pz, nameLen) == 0 && (pSrcItem->pVar.nLen == nameLen))) {
         srcFound = true;
       }
 
-      if ((!dstFound) && strncasecmp(tagName, pDstItem->pVar.pz, nameLen) == 0) {
+      //todo extract method
+      if ((!dstFound) && (strncasecmp(tagName, pDstItem->pVar.pz, nameLen) == 0 && (pDstItem->pVar.nLen == nameLen))) {
         dstFound = true;
       }
     }
diff --git a/src/system/src/mgmtMeter.c b/src/system/src/mgmtMeter.c
index 7c46f9f9a8c65aa521cdf10743be19bfa478bf80..f8ac13061dfad20535a06c203665ad4cc3d4874a 100644
--- a/src/system/src/mgmtMeter.c
+++ b/src/system/src/mgmtMeter.c
@@ -1621,7 +1621,7 @@ int32_t mgmtMeterModifyTagNameByCol(STabObj *pMetric, uint32_t col, const char *
     return TSDB_CODE_APP_ERROR;
   }
 
-  mError("Succeed to modify table %s tag column", pMetric->meterId);
+  mTrace("Succeed to modify table %s tag column", pMetric->meterId);
   return TSDB_CODE_SUCCESS;
 }