diff --git a/src/client/src/tscSql.c b/src/client/src/tscSql.c
index 9ad38e33600bdc1c6fb10182ce25f5bd38e936ac..bb0d8005c2d7234b5a9dca1cc788239ece088965 100644
--- a/src/client/src/tscSql.c
+++ b/src/client/src/tscSql.c
@@ -284,16 +284,18 @@ void taos_close(TAOS *taos) {
     return;
   }
 
-  SSqlObj* pHb = (SSqlObj*)taosAcquireRef(tscObjRef, pObj->hbrid);
-  if (pHb != NULL) {
-    if (pHb->rpcRid > 0) {  // wait for rsp from dnode
-      rpcCancelRequest(pHb->rpcRid);
-      pHb->rpcRid = -1;
-    }
+  if (RID_VALID(pObj->hbrid)) {
+    SSqlObj* pHb = (SSqlObj*)taosAcquireRef(tscObjRef, pObj->hbrid);
+    if (pHb != NULL) {
+      if (RID_VALID(pHb->rpcRid)) {  // wait for rsp from dnode
+        rpcCancelRequest(pHb->rpcRid);
+        pHb->rpcRid = -1;
+      }
 
-    tscDebug("%p HB is freed", pHb);
-    taosReleaseRef(tscObjRef, pHb->self);
-    taos_free_result(pHb);
+      tscDebug("%p HB is freed", pHb);
+      taosReleaseRef(tscObjRef, pHb->self);
+      taos_free_result(pHb);
+    }
   }
 
   tscDebug("%p all sqlObj are freed, free tscObj and close dnodeConn:%p", pObj, pObj->pDnodeConn);
diff --git a/src/util/inc/tref.h b/src/util/inc/tref.h
index cd5092f30a290c51de49e38b0226bbed637dc0e6..085c10c55198fc92bfacb0628c38f05da508bfb9 100644
--- a/src/util/inc/tref.h
+++ b/src/util/inc/tref.h
@@ -52,6 +52,8 @@ void *taosIterateRef(int rsetId, int64_t rid);
 // return the number of references in system
 int  taosListRef();  
 
+#define RID_VALID(x) ((x) > 0)
+
 /* sample code to iterate the refs 
 
 void demoIterateRefs(int rsetId) {