diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index 97670521aa24c08bf6a7f42b2ccaf629fad19e2e..fddf1b64a1857bee07f0e27a3dcae8c6443480f5 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -547,7 +547,7 @@ static int32_t tscEstimateQueryMsgSize(SSqlCmd *pCmd, int32_t clauseIndex) {
   int32_t srcColListSize = (int32_t)(taosArrayGetSize(pQueryInfo->colList) * sizeof(SColumnInfo));
 
   size_t  numOfExprs = tscSqlExprNumOfExprs(pQueryInfo);
-  int32_t exprSize = (int32_t)(sizeof(SSqlFuncMsg) * numOfExprs);
+  int32_t exprSize = (int32_t)(sizeof(SSqlFuncMsg) * numOfExprs * 2);
 
   int32_t tsBufSize = (pQueryInfo->tsBuf != NULL) ? pQueryInfo->tsBuf->fileSize : 0;