diff --git a/source/client/inc/clientInt.h b/source/client/inc/clientInt.h
index 48efe89361ac308ad20e6eca05a498e75b69c572..9225d671315723038cb61a0f21735103c3a64466 100644
--- a/source/client/inc/clientInt.h
+++ b/source/client/inc/clientInt.h
@@ -66,7 +66,7 @@ enum {
 typedef struct SAppInstInfo SAppInstInfo;
 
 typedef struct {
-  char* key;
+  char*   key;
   // statistics
   int32_t reportCnt;
   int32_t connKeyCnt;
@@ -118,6 +118,7 @@ struct SAppInstInfo {
   uint64_t           clusterId;
   void*              pTransporter;
   SAppHbMgr*         pAppHbMgr;
+  char*              instKey;
 };
 
 typedef struct SAppInfo {
@@ -336,6 +337,7 @@ int  hbHandleRsp(SClientHbBatchRsp* hbRsp);
 // cluster level
 SAppHbMgr* appHbMgrInit(SAppInstInfo* pAppInstInfo, char* key);
 void       appHbMgrCleanup(void);
+void       hbRemoveAppHbMrg(SAppHbMgr **pAppHbMgr);
 
 // conn level
 int  hbRegisterConn(SAppHbMgr* pAppHbMgr, int64_t tscRefId, int64_t clusterId, int8_t connType);
diff --git a/source/client/src/clientEnv.c b/source/client/src/clientEnv.c
index cad1b4b1cf25495ac82a44d9a4d42d678cbf044d..f5b5c48d470a32a49a38bb1b2652fafd4f65435f 100644
--- a/source/client/src/clientEnv.c
+++ b/source/client/src/clientEnv.c
@@ -79,13 +79,13 @@ static void deregisterRequest(SRequestObj *pRequest) {
 }
 
 // todo close the transporter properly
-void closeTransporter(STscObj *pTscObj) {
-  if (pTscObj == NULL || pTscObj->pAppInfo->pTransporter == NULL) {
+void closeTransporter(SAppInstInfo *pAppInfo) {
+  if (pAppInfo == NULL || pAppInfo->pTransporter == NULL) {
     return;
   }
 
-  tscDebug("free transporter:%p in connObj: 0x%" PRIx64, pTscObj->pAppInfo->pTransporter, pTscObj->id);
-  rpcClose(pTscObj->pAppInfo->pTransporter);
+  tscDebug("free transporter:%p in app inst %p", pAppInfo->pTransporter, pAppInfo);
+  rpcClose(pAppInfo->pTransporter);
 }
 
 static bool clientRpcRfp(int32_t code) {
@@ -130,6 +130,21 @@ void closeAllRequests(SHashObj *pRequests) {
   }
 }
 
+void destroyAppInst(SAppInstInfo* pAppInfo) {
+  tscDebug("destroy app inst mgr %p", pAppInfo);
+  
+  hbRemoveAppHbMrg(&pAppInfo->pAppHbMgr);
+  taosHashRemove(appInfo.pInstMap, pAppInfo->instKey, strlen(pAppInfo->instKey));
+  taosMemoryFreeClear(pAppInfo->instKey);
+  closeTransporter(pAppInfo);
+  
+  taosThreadMutexLock(&pAppInfo->qnodeMutex);
+  taosArrayDestroy(pAppInfo->pQnodeList);
+  taosThreadMutexUnlock(&pAppInfo->qnodeMutex);  
+
+  taosMemoryFree(pAppInfo);
+}
+
 void destroyTscObj(void *pObj) {
   STscObj *pTscObj = pObj;
 
@@ -138,11 +153,12 @@ void destroyTscObj(void *pObj) {
   int64_t connNum = atomic_sub_fetch_64(&pTscObj->pAppInfo->numOfConns, 1);
   closeAllRequests(pTscObj->pRequests);
   schedulerStopQueryHb(pTscObj->pAppInfo->pTransporter);
+  tscDebug("connObj 0x%" PRIx64 " p:%p destroyed, remain inst totalConn:%" PRId64, pTscObj->id, pTscObj, 
+           pTscObj->pAppInfo->numOfConns);
+
   if (0 == connNum) {
-    closeTransporter(pTscObj);
+    destroyAppInst(pTscObj->pAppInfo);
   }
-  tscDebug("connObj 0x%" PRIx64 " p:%p destroyed, totalConn:%" PRId64, pTscObj->id, pTscObj, 
-           pTscObj->pAppInfo->numOfConns);
   taosThreadMutexDestroy(&pTscObj->mutex);
   taosMemoryFreeClear(pTscObj);
 }
@@ -174,6 +190,8 @@ void *createTscObj(const char *user, const char *auth, const char *db, int32_t c
   pObj->id = taosAddRef(clientConnRefPool, pObj);
   pObj->schemalessType = 1;
 
+  atomic_add_fetch_64(&pObj->pAppInfo->numOfConns, 1);
+
   tscDebug("connObj created, 0x%" PRIx64 ",p:%p", pObj->id, pObj);
   return pObj;
 }
diff --git a/source/client/src/clientHb.c b/source/client/src/clientHb.c
index 0681b5d0a5dc970c835a9a559a9e7e74a75f86be..4f4bb83fe5b0fe3d8ba0143be46790d7b9674e0c 100644
--- a/source/client/src/clientHb.c
+++ b/source/client/src/clientHb.c
@@ -790,22 +790,40 @@ SAppHbMgr *appHbMgrInit(SAppInstInfo *pAppInstInfo, char *key) {
   return pAppHbMgr;
 }
 
+void hbFreeAppHbMgr(SAppHbMgr *pTarget) {
+  void *pIter = taosHashIterate(pTarget->activeInfo, NULL);
+  while (pIter != NULL) {
+    SClientHbReq *pOneReq = pIter;
+    tFreeClientHbReq(pOneReq);
+    pIter = taosHashIterate(pTarget->activeInfo, pIter);
+  }
+  taosHashCleanup(pTarget->activeInfo);
+  pTarget->activeInfo = NULL;
+  
+  taosMemoryFree(pTarget->key);
+  taosMemoryFree(pTarget);
+}
+
+void hbRemoveAppHbMrg(SAppHbMgr **pAppHbMgr) {
+  taosThreadMutexLock(&clientHbMgr.lock);
+  int32_t mgrSize = taosArrayGetSize(clientHbMgr.appHbMgrs);
+  for (int32_t i = 0; i < mgrSize; ++i) {
+    SAppHbMgr *pItem = taosArrayGetP(clientHbMgr.appHbMgrs, i);
+    if (pItem == *pAppHbMgr) {
+      hbFreeAppHbMgr(*pAppHbMgr);
+      *pAppHbMgr = NULL;
+      taosArrayRemove(clientHbMgr.appHbMgrs, i);
+      break;
+    }
+  }
+  taosThreadMutexUnlock(&clientHbMgr.lock);
+}
+
 void appHbMgrCleanup(void) {
   int sz = taosArrayGetSize(clientHbMgr.appHbMgrs);
   for (int i = 0; i < sz; i++) {
     SAppHbMgr *pTarget = taosArrayGetP(clientHbMgr.appHbMgrs, i);
-
-    void *pIter = taosHashIterate(pTarget->activeInfo, NULL);
-    while (pIter != NULL) {
-      SClientHbReq *pOneReq = pIter;
-      tFreeClientHbReq(pOneReq);
-      pIter = taosHashIterate(pTarget->activeInfo, pIter);
-    }
-    taosHashCleanup(pTarget->activeInfo);
-    pTarget->activeInfo = NULL;
-
-    taosMemoryFree(pTarget->key);
-    taosMemoryFree(pTarget);
+    hbFreeAppHbMgr(pTarget);
   }
 }
 
diff --git a/source/client/src/clientImpl.c b/source/client/src/clientImpl.c
index d3510b91ae7fc3d606823cbc8ff8c61835c1ba3a..8c6304632366acdc272eea1f016eaa6e70973b2c 100644
--- a/source/client/src/clientImpl.c
+++ b/source/client/src/clientImpl.c
@@ -122,7 +122,10 @@ STscObj* taos_connect_internal(const char* ip, const char* user, const char* pas
     p->pTransporter = openTransporter(user, secretEncrypt, tsNumOfCores);
     p->pAppHbMgr = appHbMgrInit(p, key);
     taosHashPut(appInfo.pInstMap, key, strlen(key), &p, POINTER_BYTES);
-
+    p->instKey = key;
+    key = NULL;
+    tscDebug("new app inst mgr %p, user:%s, ip:%s, port:%d", p, user, ip, port);
+    
     pInst = &p;
   }
 
diff --git a/source/client/src/clientMsgHandler.c b/source/client/src/clientMsgHandler.c
index 818762eff6a8f75e30100e2ade15cf943e98563c..5c30df4ae2448f3443b4f32b92e23c8ebc96e4df 100644
--- a/source/client/src/clientMsgHandler.c
+++ b/source/client/src/clientMsgHandler.c
@@ -87,7 +87,6 @@ int32_t processConnectRsp(void* param, const SDataBuf* pMsg, int32_t code) {
 
   // update the appInstInfo
   pTscObj->pAppInfo->clusterId = connectRsp.clusterId;
-  atomic_add_fetch_64(&pTscObj->pAppInfo->numOfConns, 1);
 
   pTscObj->connType = connectRsp.connType;
 
diff --git a/source/libs/catalog/src/ctgAsync.c b/source/libs/catalog/src/ctgAsync.c
index 6184d13533eb2b6e0c05a031e009dcd1d5a4c059..139539821c34673391622831578a00e212bc8fe1 100644
--- a/source/libs/catalog/src/ctgAsync.c
+++ b/source/libs/catalog/src/ctgAsync.c
@@ -789,6 +789,8 @@ _return:
 
 int32_t ctgCallUserCb(void* param) {
   SCtgJob* pJob = (SCtgJob*)param;
+
+  //taosSsleep(2);
   
   (*pJob->userFp)(&pJob->jobRes, pJob->userParam, pJob->jobResCode);
 
diff --git a/tests/script/api/stopquery.c b/tests/script/api/stopquery.c
index 4c7964c98350f1d24bb6c76ffdb5aef5746e1933..0008aa3303d9a6cb377323791f31cdbdc755a95e 100644
--- a/tests/script/api/stopquery.c
+++ b/tests/script/api/stopquery.c
@@ -368,6 +368,7 @@ void *closeThreadFp(void *arg) {
   while (true) {
     if (qParam->taos) {
       usleep(rand() % 10000);
+      //usleep(1000000);
       taos_close(qParam->taos);
       break;
     }