diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index 06578916bb2f06f72183920c3dddf447835d3907..1882aa1850754d8da3c84dd0b50fe68569d91d93 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -89,16 +89,18 @@ typedef struct {
   STSCursor   cur;
 } SQueryStatusInfo;
 
+#if 0
 static UNUSED_FUNC void *u_malloc (size_t __size) {
-//  uint32_t v = rand();
-//  if (v % 5 <= 1) {
-//    return NULL;
-//  } else {
+  uint32_t v = rand();
+  if (v % 5 <= 1) {
+    return NULL;
+  } else {
     return malloc(__size);
-//  }
+  }
 }
 
 #define malloc  u_malloc
+#endif
 
 #define CLEAR_QUERY_STATUS(q, st)   ((q)->status &= (~(st)))
 #define GET_NUM_OF_TABLEGROUP(q)    taosArrayGetSize((q)->tableqinfoGroupInfo.pGroupList)