diff --git a/src/client/src/tscAsync.c b/src/client/src/tscAsync.c
index e75ce8dc0106bafa53411f585ad8b708c1c1bf99..b00e82f65a1b79e90ae41362466ff2b971ec8557 100644
--- a/src/client/src/tscAsync.c
+++ b/src/client/src/tscAsync.c
@@ -334,6 +334,22 @@ bool appendTagsFilter(SSqlObj* pSql) {
     return false;
   }
 
+  // check tags is blank
+  size_t len = strlen(pTscObj->tags);
+  char* p = pTscObj->tags;
+  bool blank = true;
+  while(*p != 0) {
+    if(*p != ' ') {
+      blank = false;
+      break;
+    }
+  }
+  // result
+  if(blank) {
+    tscDebug("TAGS 0x%" PRIx64 " tags is all blank. user=%s", pSql->self, pTscObj->user);
+    return false;
+  }
+
   char * p = insertTags(pSql->sqlstr, pTscObj->tags);
   if(p == NULL) {
     return false;
diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 8eb7f15fde6a878ff617e047826df91c9e2c1878..6fbc8a5e19e87ecfd9a535a1491a882a26adc06b 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -862,7 +862,6 @@ int32_t tscValidateSqlInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
       const char* msg3 = "name too long";
       const char* msg5 = "invalid user rights";
       const char* msg7 = "not support options";
-      const char* msg8 = "tags filter length must over 3 bytes.";
 
       pCmd->command = pInfo->type;
 
@@ -901,10 +900,7 @@ int32_t tscValidateSqlInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
           } else {
             return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg5);
           }
-        } else if (pUser->type == TSDB_ALTER_USER_TAGS) {
-          SStrToken* pTags = &pUser->tags;
-          if(pTags->n < 4)
-            return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg8);
+        }
        } else {
           return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg7);
         }
diff --git a/src/mnode/src/mnodeUser.c b/src/mnode/src/mnodeUser.c
index 6d6ccb933e414fd8d07c5282753685603a7e1be2..63e41bf6527684f6239e9c0af67a1e27bcc199f1 100644
--- a/src/mnode/src/mnodeUser.c
+++ b/src/mnode/src/mnodeUser.c
@@ -97,7 +97,7 @@ static int32_t mnodeUserActionDecode(SSdbRow *pRow) {
   SUserObj *pUser = (SUserObj *)calloc(1, sizeof(SUserObj));
   if (pUser == NULL) return TSDB_CODE_MND_OUT_OF_MEMORY;
 
-  memcpy(pUser, pRow->rowData, tsUserUpdateSize);
+  memcpy(pUser, pRow->rowData, pRow->rowSize);
   pRow->pObj = pUser;
   return TSDB_CODE_SUCCESS;
 }