diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index 5e3acaa0b742ae53622cc610b0f3383f3e071ff4..a011ac2f3a99af128c7fc6fa451bd2a8924a9d2d 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -191,9 +191,16 @@ void tscProcessHeartBeatRsp(void *param, TAOS_RES *tres, int code) {
 void tscProcessActivityTimer(void *handle, void *tmrId) {
   int64_t rid = (int64_t) handle;
   STscObj *pObj = taosAcquireRef(tscRefId, rid);
-  if (pObj == NULL) return; 
+  if (pObj == NULL) {
+    return;
+  }
 
   SSqlObj* pHB = taosAcquireRef(tscObjRef, pObj->hbrid);
+  if (pHB == NULL) {
+    taosReleaseRef(tscRefId, rid);
+    return;
+  }
+
   assert(pHB->self == pObj->hbrid);
 
   pHB->retry = 0;