diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index 3fab93aa76b9e76c359591b7c055847e74006296..2e7a99f2fb89bf9cddc6f45217197b77f9eb8df5 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -567,7 +567,7 @@ static int32_t tscEstimateQueryMsgSize(SSqlCmd *pCmd, int32_t clauseIndex) {
     int32_t totalTables = 0;
     for (int32_t i = 0; i < numOfGroups; ++i) {
       SVgroupTableInfo *pTableInfo = taosArrayGet(pTableMetaInfo->pVgroupTables, i);
-      totalTables += taosArrayGetSize(pTableInfo->itemList);
+      totalTables += (int32_t) taosArrayGetSize(pTableInfo->itemList);
     }
 
     tableSerialize = totalTables * sizeof(STableIdInfo);