diff --git a/src/client/src/tscFunctionImpl.c b/src/client/src/tscFunctionImpl.c
index b05e82b39a91195e26c3fd926e70ff75a5eb6713..a0deaa519a4ec0c6829cbfa70261b3efa28535d9 100644
--- a/src/client/src/tscFunctionImpl.c
+++ b/src/client/src/tscFunctionImpl.c
@@ -151,7 +151,6 @@ typedef struct SRateInfo {
   double  sum;        // for sum/avg
 } SRateInfo;
 
-
 int32_t getResultDataInfo(int32_t dataType, int32_t dataBytes, int32_t functionId, int32_t param, int16_t *type,
                           int16_t *bytes, int32_t *interBytes, int16_t extLength, bool isSuperTable) {
   if (!isValidDataType(dataType, dataBytes)) {
diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 372e81d7371debe904ac7ad1e6a9caecb54ccb28..47f679a922e5f389e040a61a9e462979574886b5 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -348,7 +348,7 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg1);
       }
 
-      if (pToken->n >= TSDB_TABLE_NAME_LEN) {
+      if (tscValidateTableNameLength(pToken->n)) {
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg2);
       }
 
@@ -1056,7 +1056,7 @@ int32_t setObjFullName(char* fullName, const char* account, SSQLToken* pDB, SSQL
       totalLen += 1;
 
       /* here we only check the table name length limitation */
-      if (tableName->n > TSDB_TABLE_NAME_LEN) {
+      if (!tscValidateTableNameLength(tableName->n)) {
         return TSDB_CODE_TSC_INVALID_SQL;
       }
     } else {  // pDB == NULL, the db prefix name is specified in tableName
@@ -1402,9 +1402,7 @@ int32_t addProjectionExprAndResultField(SQueryInfo* pQueryInfo, tSQLExprItem* pI
     }
 
     if (index.columnIndex == TSDB_TBNAME_COLUMN_INDEX) {
-      SSchema colSchema = {.type = TSDB_DATA_TYPE_BINARY, .bytes = (TSDB_TABLE_NAME_LEN - 1) + VARSTR_HEADER_SIZE};
-      strcpy(colSchema.name, TSQL_TBNAME_L);
-
+      SSchema colSchema = tGetTableNameColumnSchema();
       tscAddSpecialColumnForSelect(pQueryInfo, startPos, TSDB_FUNC_TAGPRJ, &index, &colSchema, true);
     } else {
       STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, index.tableIndex);
@@ -1914,9 +1912,7 @@ int32_t addExprAndResultField(SQueryInfo* pQueryInfo, int32_t colIndex, tSQLExpr
       
       SSchema s = {0};
       if (index.columnIndex == TSDB_TBNAME_COLUMN_INDEX) {
-        s.bytes = TSDB_TABLE_NAME_LEN + VARSTR_HEADER_SIZE;
-        s.type  = TSDB_DATA_TYPE_BINARY;
-        s.colId = TSDB_TBNAME_COLUMN_INDEX;
+        s = tGetTableNameColumnSchema();
       } else {
         s = pTagSchema[index.columnIndex];
       }
@@ -2230,7 +2226,7 @@ int32_t setShowInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg6);
       }
 
-      if (pCmd->payloadLen >= TSDB_TABLE_NAME_LEN) {
+      if (!tscValidateTableNameLength(pCmd->payloadLen)) {
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg2);
       }
     }
@@ -2861,7 +2857,7 @@ static int32_t tablenameListToString(tSQLExpr* pExpr, SStringBuilder* sb) {
       taosStringBuilderAppendString(sb, TBNAME_LIST_SEP);
     }
 
-    if (pSub->val.nLen <= 0 || pSub->val.nLen > TSDB_TABLE_NAME_LEN) {
+    if (pSub->val.nLen <= 0 || !tscValidateTableNameLength(pSub->val.nLen)) {
       return TSDB_CODE_TSC_INVALID_SQL;
     }
   }
@@ -5232,9 +5228,10 @@ static int32_t doAddGroupbyColumnsOnDemand(SQueryInfo* pQueryInfo) {
   
     int16_t colIndex = pColIndex->colIndex;
     if (colIndex == TSDB_TBNAME_COLUMN_INDEX) {
-      type = TSDB_DATA_TYPE_BINARY;
-      bytes = (TSDB_TABLE_NAME_LEN - 1) + VARSTR_HEADER_SIZE; // todo extract method
-      name = TSQL_TBNAME_L;
+      SSchema s = tGetTableNameColumnSchema();
+      type = s.type;
+      bytes = s.bytes;
+      name = s.name;
     } else {
       if (TSDB_COL_IS_TAG(pColIndex->flag)) {
         SSchema* tagSchema = tscGetTableTagSchema(pTableMetaInfo->pTableMeta);
diff --git a/src/client/src/tscSchemaUtil.c b/src/client/src/tscSchemaUtil.c
index 88417addf635fd3cf0824cf6774112c1bfd5a05f..439aa7c1dedc1f9b301d3aeb08ccb7d68ac9ab00 100644
--- a/src/client/src/tscSchemaUtil.c
+++ b/src/client/src/tscSchemaUtil.c
@@ -50,14 +50,6 @@ int32_t tscGetNumOfColumns(const STableMeta* pTableMeta) {
 
 SSchema *tscGetTableSchema(const STableMeta *pTableMeta) {
   assert(pTableMeta != NULL);
-  
-//  if (pTableMeta->tableType == TSDB_CHILD_TABLE) {
-//    STableMeta* pSTableMeta = pTableMeta->pSTable;
-//    assert (pSTableMeta != NULL);
-//
-//    return pSTableMeta->schema;
-//  }
-  
   return (SSchema*) pTableMeta->schema;
 }
 
diff --git a/src/common/inc/tname.h b/src/common/inc/tname.h
index 810d7f492c8fcd96aa7a4b2032f05142e8494e86..d2008c9ff8181b54db83fdd92f777ba74489ce73 100644
--- a/src/common/inc/tname.h
+++ b/src/common/inc/tname.h
@@ -23,5 +23,8 @@ void extractTableName(const char *tableId, char *name);
 
 char* extractDBName(const char *tableId, char *name);
 
+SSchema tGetTableNameColumnSchema();
+
+bool tscValidateTableNameLength(size_t len);
 
 #endif  // TDENGINE_NAME_H
diff --git a/src/common/src/tname.c b/src/common/src/tname.c
index d2f5dfc4f75a96e725dc719a4d348472e36d3564..2514ed26e55e54eddf54d83933beecdfbf4e06fa 100644
--- a/src/common/src/tname.c
+++ b/src/common/src/tname.c
@@ -37,3 +37,16 @@ char* extractDBName(const char* tableId, char* name) {
   
   return strncpy(name, &tableId[offset1 + 1], len);
 }
+
+SSchema tGetTableNameColumnSchema() {
+  SSchema s = {0};
+  s.bytes = TSDB_TABLE_NAME_LEN - 1 + VARSTR_HEADER_SIZE;
+  s.type  = TSDB_DATA_TYPE_BINARY;
+  s.colId = TSDB_TBNAME_COLUMN_INDEX;
+  strncpy(s.name, TSQL_TBNAME_L, TSDB_COL_NAME_LEN);
+  return s;
+}
+
+bool tscValidateTableNameLength(size_t len) {
+  return len < TSDB_TABLE_NAME_LEN;
+}
\ No newline at end of file
diff --git a/src/inc/taosdef.h b/src/inc/taosdef.h
index 251e3a9e4031cc0c4e48fe7c89ba1f1c1535c704..be9c0b5ef6b3476f53b2055c3aaeb47c10f0c716 100644
--- a/src/inc/taosdef.h
+++ b/src/inc/taosdef.h
@@ -200,7 +200,7 @@ void tsDataSwap(void *pLeft, void *pRight, int32_t type, int32_t size);
 #define TSDB_MIN_COLUMNS          2       //PRIMARY COLUMN(timestamp) + other columns
 
 #define TSDB_NODE_NAME_LEN        64
-#define TSDB_TABLE_NAME_LEN       193
+#define TSDB_TABLE_NAME_LEN       193     // it is a null-terminated string
 #define TSDB_DB_NAME_LEN          33
 #define TSDB_COL_NAME_LEN         65
 #define TSDB_MAX_SAVED_SQL_LEN    TSDB_MAX_COLUMNS * 64
diff --git a/src/mnode/src/mnodeTable.c b/src/mnode/src/mnodeTable.c
index a2ddd9893f50495d3235d5feb8cc513638569209..adb8e261d4c2408b7ea93ad9b3d3073f905b1419 100644
--- a/src/mnode/src/mnodeTable.c
+++ b/src/mnode/src/mnodeTable.c
@@ -1078,8 +1078,9 @@ static int32_t mnodeGetShowSuperTableMeta(STableMetaMsg *pMeta, SShowObj *pShow,
   int32_t cols = 0;
   SSchema *pSchema = pMeta->schema;
 
-  pShow->bytes[cols] = (TSDB_TABLE_NAME_LEN - 1) + VARSTR_HEADER_SIZE;
-  pSchema[cols].type = TSDB_DATA_TYPE_BINARY;
+  SSchema tbnameSchema = tGetTableNameColumnSchema();
+  pShow->bytes[cols] = tbnameSchema.bytes;
+  pSchema[cols].type = tbnameSchema.type;
   strcpy(pSchema[cols].name, "name");
   pSchema[cols].bytes = htons(pShow->bytes[cols]);
   cols++;
@@ -2079,8 +2080,9 @@ static int32_t mnodeGetShowTableMeta(STableMetaMsg *pMeta, SShowObj *pShow, void
   int32_t cols = 0;
   SSchema *pSchema = pMeta->schema;
 
-  pShow->bytes[cols] = (TSDB_TABLE_NAME_LEN - 1) + VARSTR_HEADER_SIZE;
-  pSchema[cols].type = TSDB_DATA_TYPE_BINARY;
+  SSchema s = tGetTableNameColumnSchema();
+  pShow->bytes[cols] = s.bytes;
+  pSchema[cols].type = s.type;
   strcpy(pSchema[cols].name, "table_name");
   pSchema[cols].bytes = htons(pShow->bytes[cols]);
   cols++;
@@ -2097,8 +2099,9 @@ static int32_t mnodeGetShowTableMeta(STableMetaMsg *pMeta, SShowObj *pShow, void
   pSchema[cols].bytes = htons(pShow->bytes[cols]);
   cols++;
 
-  pShow->bytes[cols] = (TSDB_TABLE_NAME_LEN - 1) + VARSTR_HEADER_SIZE;
-  pSchema[cols].type = TSDB_DATA_TYPE_BINARY;
+  SSchema tbCol = tGetTableNameColumnSchema();
+  pShow->bytes[cols] = tbCol.bytes;
+  pSchema[cols].type = tbCol.type;
   strcpy(pSchema[cols].name, "stable_name");
   pSchema[cols].bytes = htons(pShow->bytes[cols]);
   cols++;
@@ -2268,8 +2271,9 @@ static int32_t mnodeGetStreamTableMeta(STableMetaMsg *pMeta, SShowObj *pShow, vo
   int32_t cols = 0;
   SSchema *pSchema = pMeta->schema;
 
-  pShow->bytes[cols] = (TSDB_TABLE_NAME_LEN - 1) + VARSTR_HEADER_SIZE;
-  pSchema[cols].type = TSDB_DATA_TYPE_BINARY;
+  SSchema tbnameColSchema = tGetTableNameColumnSchema();
+  pShow->bytes[cols] = tbnameColSchema.bytes;
+  pSchema[cols].type = tbnameColSchema.type;
   strcpy(pSchema[cols].name, "table_name");
   pSchema[cols].bytes = htons(pShow->bytes[cols]);
   cols++;
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index cdb05d2288671f6fcb619b01f60e6437ffa5ed97..ebc06a7875ded48db61e191ba3dad189ef462294 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -1368,8 +1368,10 @@ static int32_t setupQueryRuntimeEnv(SQueryRuntimeEnv *pRuntimeEnv, int16_t order
     int32_t index = pSqlFuncMsg->colInfo.colIndex;
     if (TSDB_COL_IS_TAG(pIndex->flag)) {
       if (pIndex->colId == TSDB_TBNAME_COLUMN_INDEX) {  // todo refactor
-        pCtx->inputBytes = (TSDB_TABLE_NAME_LEN - 1) + VARSTR_HEADER_SIZE;
-        pCtx->inputType = TSDB_DATA_TYPE_BINARY;
+        SSchema s = tGetTableNameColumnSchema();
+
+        pCtx->inputBytes = s.bytes;
+        pCtx->inputType = s.type;
       } else {
         pCtx->inputBytes = pQuery->tagColList[index].bytes;
         pCtx->inputType = pQuery->tagColList[index].type;
@@ -5143,8 +5145,9 @@ static int32_t createQFunctionExprFromMsg(SQueryTableMsg *pQueryMsg, SExprInfo *
       type  = TSDB_DATA_TYPE_DOUBLE;
       bytes = tDataTypeDesc[type].nSize;
     } else if (pExprs[i].base.colInfo.colId == TSDB_TBNAME_COLUMN_INDEX && pExprs[i].base.functionId == TSDB_FUNC_TAGPRJ) {  // parse the normal column
-      type  = TSDB_DATA_TYPE_BINARY;
-      bytes = (TSDB_TABLE_NAME_LEN - 1) + VARSTR_HEADER_SIZE;
+      SSchema s = tGetTableNameColumnSchema();
+      type  = s.type;
+      bytes = s.bytes;
     } else{
       int32_t j = getColumnIndexInSource(pQueryMsg, &pExprs[i].base, pTagCols);
       assert(j < pQueryMsg->numOfCols || j < pQueryMsg->numOfTags || j == TSDB_TBNAME_COLUMN_INDEX);
@@ -5154,10 +5157,11 @@ static int32_t createQFunctionExprFromMsg(SQueryTableMsg *pQueryMsg, SExprInfo *
         type = pCol->type;
         bytes = pCol->bytes;
       } else {
-        type  = TSDB_DATA_TYPE_BINARY;
-        bytes = TSDB_TABLE_NAME_LEN + VARSTR_HEADER_SIZE;
-      }
+        SSchema s = tGetTableNameColumnSchema();
 
+        type  = s.type;
+        bytes = s.bytes;
+      }
     }
 
     int32_t param = pExprs[i].base.arg[0].argValue.i64;
@@ -6025,6 +6029,7 @@ static void buildTagQueryResult(SQInfo* pQInfo) {
     qTrace("QInfo:%p create count(tbname) query, res:%d rows:1", pQInfo, count);
   } else {  // return only the tags|table name etc.
     count = 0;
+    SSchema tbnameSchema = tGetTableNameColumnSchema();
     while(pQInfo->tableIndex < num && count < pQuery->rec.capacity) {
       int32_t i = pQInfo->tableIndex++;
       
@@ -6034,7 +6039,7 @@ static void buildTagQueryResult(SQInfo* pQInfo) {
       for(int32_t j = 0; j < pQuery->numOfOutput; ++j) {
         if (pExprInfo[j].base.colInfo.colId == TSDB_TBNAME_COLUMN_INDEX) {
           char* data = tsdbGetTableName(pQInfo->tsdb, &item->id);
-          char* dst = pQuery->sdata[j]->data + count * ((TSDB_TABLE_NAME_LEN - 1) + VARSTR_HEADER_SIZE);
+          char* dst = pQuery->sdata[j]->data + count * tbnameSchema.bytes;
           memcpy(dst, data, varDataTLen(data));
         } else {// todo refactor
           int16_t type = pExprInfo[j].type;
diff --git a/src/tsdb/src/tsdbRead.c b/src/tsdb/src/tsdbRead.c
index d3bc45e2e4706f2892b4bfd75e8b9b029aa0dc6e..e74ec3b06ad418f454b920702fc42cf5c5d1b685 100644
--- a/src/tsdb/src/tsdbRead.c
+++ b/src/tsdb/src/tsdbRead.c
@@ -1942,7 +1942,7 @@ int32_t tableGroupComparFn(const void *p1, const void *p2, const void *param) {
       f1 = (char*) pTable1->name;
       f2 = (char*) pTable2->name;
       type = TSDB_DATA_TYPE_BINARY;
-      bytes = (TSDB_TABLE_NAME_LEN - 1) + VARSTR_HEADER_SIZE;
+      bytes = tGetTableNameColumnSchema().bytes;
     } else {
       STColumn* pCol = schemaColAt(pTableGroupSupp->pTagSchema, colIndex);
       bytes = pCol->bytes;