diff --git a/include/libs/transport/trpc.h b/include/libs/transport/trpc.h
index 538aeb1a0e7927469cf90721dbbc16140c181e93..f1bab81573bd555963edf524ecfb7171ebdd44bd 100644
--- a/include/libs/transport/trpc.h
+++ b/include/libs/transport/trpc.h
@@ -78,6 +78,9 @@ typedef struct SRpcInit {
   // call back to retrieve the client auth info, for server app only
   int (*afp)(void *parent, char *tableId, char *spi, char *encrypt, char *secret, char *ckey);
 
+  // call back to keep conn or not
+  bool (*pfp)(void *parent, tmsg_t msgType);
+
   void *parent;
 } SRpcInit;
 
diff --git a/source/client/inc/clientInt.h b/source/client/inc/clientInt.h
index d7574466cdfbe15ea38145c7dd3a9d0a3895e9bb..944da5a30737800513d13fb4cecf2b4eece72575 100644
--- a/source/client/inc/clientInt.h
+++ b/source/client/inc/clientInt.h
@@ -20,17 +20,17 @@
 extern "C" {
 #endif
 
-#include "taos.h"
 #include "common.h"
-#include "tmsg.h"
+#include "parser.h"
+#include "query.h"
+#include "taos.h"
 #include "tdef.h"
 #include "tep.h"
 #include "thash.h"
 #include "tlist.h"
+#include "tmsg.h"
 #include "tmsgtype.h"
 #include "trpc.h"
-#include "query.h"
-#include "parser.h"
 
 #define CHECK_CODE_GOTO(expr, label) \
   do {                               \
@@ -46,12 +46,12 @@ extern "C" {
 typedef struct SAppInstInfo SAppInstInfo;
 
 typedef struct SHbConnInfo {
-  void         *param;
-  SClientHbReq *req;
+  void*         param;
+  SClientHbReq* req;
 } SHbConnInfo;
 
 typedef struct SAppHbMgr {
-  char   *key;
+  char* key;
   // statistics
   int32_t reportCnt;
   int32_t connKeyCnt;
@@ -62,15 +62,13 @@ typedef struct SAppHbMgr {
   // connection
   SAppInstInfo* pAppInstInfo;
   // info
-  SHashObj* activeInfo;    // hash<SClientHbKey, SClientHbReq>
-  SHashObj* connInfo;      // hash<SClientHbKey, SHbConnInfo>
+  SHashObj* activeInfo;  // hash<SClientHbKey, SClientHbReq>
+  SHashObj* connInfo;    // hash<SClientHbKey, SHbConnInfo>
 } SAppHbMgr;
 
+typedef int32_t (*FHbRspHandle)(struct SAppHbMgr* pAppHbMgr, SClientHbRsp* pRsp);
 
-typedef int32_t (*FHbRspHandle)(struct SAppHbMgr *pAppHbMgr, SClientHbRsp* pRsp);
-
-typedef int32_t (*FHbReqHandle)(SClientHbKey *connKey, void* param, SClientHbReq *req);
-
+typedef int32_t (*FHbReqHandle)(SClientHbKey* connKey, void* param, SClientHbReq* req);
 
 typedef struct SClientHbMgr {
   int8_t inited;
@@ -83,63 +81,62 @@ typedef struct SClientHbMgr {
   FHbRspHandle    rspHandle[HEARTBEAT_TYPE_MAX];
 } SClientHbMgr;
 
-
 typedef struct SQueryExecMetric {
-  int64_t      start;    // start timestamp
-  int64_t      parsed;   // start to parse
-  int64_t      send;     // start to send to server
-  int64_t      rsp;      // receive response from server
+  int64_t start;   // start timestamp
+  int64_t parsed;  // start to parse
+  int64_t send;    // start to send to server
+  int64_t rsp;     // receive response from server
 } SQueryExecMetric;
 
 typedef struct SInstanceSummary {
-  uint64_t     numOfInsertsReq;
-  uint64_t     numOfInsertRows;
-  uint64_t     insertElapsedTime;
-  uint64_t     insertBytes;         // submit to tsdb since launched.
-
-  uint64_t     fetchBytes;
-  uint64_t     queryElapsedTime;
-  uint64_t     numOfSlowQueries;
-  uint64_t     totalRequests;
-  uint64_t     currentRequests;      // the number of SRequestObj
+  uint64_t numOfInsertsReq;
+  uint64_t numOfInsertRows;
+  uint64_t insertElapsedTime;
+  uint64_t insertBytes;  // submit to tsdb since launched.
+
+  uint64_t fetchBytes;
+  uint64_t queryElapsedTime;
+  uint64_t numOfSlowQueries;
+  uint64_t totalRequests;
+  uint64_t currentRequests;  // the number of SRequestObj
 } SInstanceSummary;
 
 typedef struct SHeartBeatInfo {
-  void  *pTimer;   // timer, used to send request msg to mnode
+  void* pTimer;  // timer, used to send request msg to mnode
 } SHeartBeatInfo;
 
 struct SAppInstInfo {
-  int64_t          numOfConns;
-  SCorEpSet        mgmtEp;
-  SInstanceSummary summary;
-  SList            *pConnList;  // STscObj linked list
-  int64_t          clusterId;
-  void             *pTransporter;
-  struct SAppHbMgr *pAppHbMgr;
+  int64_t           numOfConns;
+  SCorEpSet         mgmtEp;
+  SInstanceSummary  summary;
+  SList*            pConnList;  // STscObj linked list
+  int64_t           clusterId;
+  void*             pTransporter;
+  struct SAppHbMgr* pAppHbMgr;
 };
 
 typedef struct SAppInfo {
   int64_t         startTime;
   char            appName[TSDB_APP_NAME_LEN];
-  char           *ep;
+  char*           ep;
   int32_t         pid;
   int32_t         numOfThreads;
-  SHashObj       *pInstMap;
+  SHashObj*       pInstMap;
   pthread_mutex_t mutex;
 } SAppInfo;
 
 typedef struct STscObj {
-  char             user[TSDB_USER_LEN];
-  char             pass[TSDB_PASSWORD_LEN];
-  char             db[TSDB_DB_FNAME_LEN];
-  char             ver[128];
-  int32_t          acctId;
-  uint32_t         connId;
-  int32_t          connType;
-  uint64_t         id;       // ref ID returned by taosAddRef
-  pthread_mutex_t  mutex;     // used to protect the operation on db
-  int32_t          numOfReqs; // number of sqlObj bound to this connection
-  SAppInstInfo    *pAppInfo;
+  char            user[TSDB_USER_LEN];
+  char            pass[TSDB_PASSWORD_LEN];
+  char            db[TSDB_DB_FNAME_LEN];
+  char            ver[128];
+  int32_t         acctId;
+  uint32_t        connId;
+  int32_t         connType;
+  uint64_t        id;         // ref ID returned by taosAddRef
+  pthread_mutex_t mutex;      // used to protect the operation on db
+  int32_t         numOfReqs;  // number of sqlObj bound to this connection
+  SAppInstInfo*   pAppInfo;
 } STscObj;
 
 typedef struct SMqConsumer {
@@ -147,49 +144,49 @@ typedef struct SMqConsumer {
 } SMqConsumer;
 
 typedef struct SReqResultInfo {
-  const char  *pRspMsg;
-  const char  *pData;
-  TAOS_FIELD  *fields;
-  uint32_t     numOfCols;
-  int32_t     *length;
-  TAOS_ROW     row;
-  char       **pCol;
-  uint32_t     numOfRows;
-  uint64_t     totalRows;
-  uint32_t     current;
-  bool         completed;
+  const char* pRspMsg;
+  const char* pData;
+  TAOS_FIELD* fields;
+  uint32_t    numOfCols;
+  int32_t*    length;
+  TAOS_ROW    row;
+  char**      pCol;
+  uint32_t    numOfRows;
+  uint64_t    totalRows;
+  uint32_t    current;
+  bool        completed;
 } SReqResultInfo;
 
 typedef struct SShowReqInfo {
-  int64_t         execId;        // showId/queryId
-  int32_t         vgId;
-  SArray         *pArray;        // SArray<SVgroupInfo>
-  int32_t         currentIndex;  // current accessed vgroup index.
+  int64_t execId;  // showId/queryId
+  int32_t vgId;
+  SArray* pArray;        // SArray<SVgroupInfo>
+  int32_t currentIndex;  // current accessed vgroup index.
 } SShowReqInfo;
 
 typedef struct SRequestSendRecvBody {
-  tsem_t            rspSem;        // not used now
+  tsem_t            rspSem;  // not used now
   void*             fp;
-  SShowReqInfo      showInfo;      // todo this attribute will be removed after the query framework being completed.
+  SShowReqInfo      showInfo;  // todo this attribute will be removed after the query framework being completed.
   SDataBuf          requestMsg;
-  struct SSchJob   *pQueryJob;     // query job, created according to sql query DAG.
-  struct SQueryDag *pDag;          // the query dag, generated according to the sql statement.
+  struct SSchJob*   pQueryJob;  // query job, created according to sql query DAG.
+  struct SQueryDag* pDag;       // the query dag, generated according to the sql statement.
   SReqResultInfo    resInfo;
 } SRequestSendRecvBody;
 
-#define ERROR_MSG_BUF_DEFAULT_SIZE  512
+#define ERROR_MSG_BUF_DEFAULT_SIZE 512
 
 typedef struct SRequestObj {
-  uint64_t         requestId;
-  int32_t          type;   // request type
-  STscObj         *pTscObj;
-  char            *sqlstr;  // sql string
-  int32_t          sqlLen;
-  int64_t          self;
-  char            *msgBuf;
-  void            *pInfo;   // sql parse info, generated by parser module
-  int32_t          code;
-  SQueryExecMetric metric;
+  uint64_t             requestId;
+  int32_t              type;  // request type
+  STscObj*             pTscObj;
+  char*                sqlstr;  // sql string
+  int32_t              sqlLen;
+  int64_t              self;
+  char*                msgBuf;
+  void*                pInfo;  // sql parse info, generated by parser module
+  int32_t              code;
+  SQueryExecMetric     metric;
   SRequestSendRecvBody body;
 } SRequestObj;
 
@@ -198,51 +195,52 @@ extern int32_t  clientReqRefPool;
 extern int32_t  clientConnRefPool;
 
 extern int (*handleRequestRspFp[TDMT_MAX])(void*, const SDataBuf* pMsg, int32_t code);
-int genericRspCallback(void* param, const SDataBuf* pMsg, int32_t code);
+int           genericRspCallback(void* param, const SDataBuf* pMsg, int32_t code);
 SMsgSendInfo* buildMsgInfoImpl(SRequestObj* pReqObj);
 
-int   taos_init();
+int taos_init();
 
-void* createTscObj(const char* user, const char* auth, const char *db, SAppInstInfo* pAppInfo);
-void  destroyTscObj(void*pObj);
+void* createTscObj(const char* user, const char* auth, const char* db, SAppInstInfo* pAppInfo);
+void  destroyTscObj(void* pObj);
 
 uint64_t generateRequestId();
 
-void *createRequest(STscObj* pObj, __taos_async_fn_t fp, void* param, int32_t type);
+void* createRequest(STscObj* pObj, __taos_async_fn_t fp, void* param, int32_t type);
 void  destroyRequest(SRequestObj* pRequest);
 
-char *getDbOfConnection(STscObj* pObj);
+char* getDbOfConnection(STscObj* pObj);
 void  setConnectionDB(STscObj* pTscObj, const char* db);
 
 void taos_init_imp(void);
-int  taos_options_imp(TSDB_OPTION option, const char *str);
+int  taos_options_imp(TSDB_OPTION option, const char* str);
 
-void* openTransporter(const char *user, const char *auth, int32_t numOfThreads);
+void* openTransporter(const char* user, const char* auth, int32_t numOfThreads);
 
+bool persistConnForSpecificMsg(void* parenct, tmsg_t msgType);
 void processMsgFromServer(void* parent, SRpcMsg* pMsg, SEpSet* pEpSet);
 
 void initMsgHandleFp();
 
-TAOS *taos_connect_internal(const char *ip, const char *user, const char *pass, const char *auth, const char *db, uint16_t port);
-
-void *doFetchRow(SRequestObj* pRequest);
+TAOS* taos_connect_internal(const char* ip, const char* user, const char* pass, const char* auth, const char* db,
+                            uint16_t port);
 
-void  setResultDataPtr(SReqResultInfo* pResultInfo, TAOS_FIELD* pFields, int32_t numOfCols, int32_t numOfRows);
+void* doFetchRow(SRequestObj* pRequest);
 
+void setResultDataPtr(SReqResultInfo* pResultInfo, TAOS_FIELD* pFields, int32_t numOfCols, int32_t numOfRows);
 
-int32_t buildRequest(STscObj *pTscObj, const char *sql, int sqlLen, SRequestObj** pRequest);
+int32_t buildRequest(STscObj* pTscObj, const char* sql, int sqlLen, SRequestObj** pRequest);
 
 int32_t parseSql(SRequestObj* pRequest, SQueryNode** pQuery);
 
-// --- heartbeat 
+// --- heartbeat
 // global, called by mgmt
 int  hbMgrInit();
 void hbMgrCleanUp();
 int  hbHandleRsp(SClientHbBatchRsp* hbRsp);
 
 // cluster level
-SAppHbMgr* appHbMgrInit(SAppInstInfo* pAppInstInfo, char *key);
-void appHbMgrCleanup(void);
+SAppHbMgr* appHbMgrInit(SAppInstInfo* pAppInstInfo, char* key);
+void       appHbMgrCleanup(void);
 
 // conn level
 int  hbRegisterConn(SAppHbMgr* pAppHbMgr, int32_t connId, int64_t clusterId, int32_t hbType);
@@ -253,7 +251,6 @@ int hbAddConnInfo(SAppHbMgr* pAppHbMgr, SClientHbKey connKey, void* key, void* v
 // --- mq
 void hbMgrInitMqHbRspHandle();
 
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/client/src/clientEnv.c b/source/client/src/clientEnv.c
index cb73701bfa389ede7ed8073728acd7d418a369c5..af131f7624384581550802ad029878caa11be167 100644
--- a/source/client/src/clientEnv.c
+++ b/source/client/src/clientEnv.c
@@ -13,16 +13,16 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "os.h"
 #include "catalog.h"
 #include "clientInt.h"
 #include "clientLog.h"
+#include "os.h"
 #include "query.h"
 #include "scheduler.h"
-#include "tmsg.h"
 #include "tcache.h"
 #include "tconfig.h"
 #include "tglobal.h"
+#include "tmsg.h"
 #include "tnote.h"
 #include "tref.h"
 #include "trpc.h"
@@ -30,16 +30,16 @@
 #include "ttimezone.h"
 
 #define TSC_VAR_NOT_RELEASE 1
-#define TSC_VAR_RELEASED    0
+#define TSC_VAR_RELEASED 0
 
-SAppInfo   appInfo;
-int32_t    clientReqRefPool  = -1;
-int32_t    clientConnRefPool = -1;
+SAppInfo appInfo;
+int32_t  clientReqRefPool = -1;
+int32_t  clientConnRefPool = -1;
 
 static pthread_once_t tscinit = PTHREAD_ONCE_INIT;
-volatile int32_t tscInitRes = 0;
+volatile int32_t      tscInitRes = 0;
 
-static void registerRequest(SRequestObj* pRequest) {
+static void registerRequest(SRequestObj *pRequest) {
   STscObj *pTscObj = (STscObj *)taosAcquireRef(clientConnRefPool, pRequest->pTscObj->id);
   assert(pTscObj != NULL);
 
@@ -53,23 +53,25 @@ static void registerRequest(SRequestObj* pRequest) {
 
     int32_t total = atomic_add_fetch_32(&pSummary->totalRequests, 1);
     int32_t currentInst = atomic_add_fetch_32(&pSummary->currentRequests, 1);
-    tscDebug("0x%" PRIx64 " new Request from connObj:0x%" PRIx64 ", current:%d, app current:%d, total:%d, reqId:0x%"PRIx64, pRequest->self,
-             pRequest->pTscObj->id, num, currentInst, total, pRequest->requestId);
+    tscDebug("0x%" PRIx64 " new Request from connObj:0x%" PRIx64
+             ", current:%d, app current:%d, total:%d, reqId:0x%" PRIx64,
+             pRequest->self, pRequest->pTscObj->id, num, currentInst, total, pRequest->requestId);
   }
 }
 
-static void deregisterRequest(SRequestObj* pRequest) {
+static void deregisterRequest(SRequestObj *pRequest) {
   assert(pRequest != NULL);
 
-  STscObj* pTscObj = pRequest->pTscObj;
-  SInstanceSummary* pActivity = &pTscObj->pAppInfo->summary;
+  STscObj *         pTscObj = pRequest->pTscObj;
+  SInstanceSummary *pActivity = &pTscObj->pAppInfo->summary;
 
   int32_t currentInst = atomic_sub_fetch_32(&pActivity->currentRequests, 1);
   int32_t num = atomic_sub_fetch_32(&pTscObj->numOfReqs, 1);
 
   int64_t duration = taosGetTimestampMs() - pRequest->metric.start;
-  tscDebug("0x%"PRIx64" free Request from connObj: 0x%"PRIx64", reqId:0x%"PRIx64" elapsed:%"PRIu64" ms, current:%d, app current:%d", pRequest->self, pTscObj->id,
-      pRequest->requestId, duration, num, currentInst);
+  tscDebug("0x%" PRIx64 " free Request from connObj: 0x%" PRIx64 ", reqId:0x%" PRIx64 " elapsed:%" PRIu64
+           " ms, current:%d, app current:%d",
+           pRequest->self, pTscObj->id, pRequest->requestId, duration, num, currentInst);
   taosReleaseRef(clientConnRefPool, pTscObj->id);
 }
 
@@ -79,8 +81,8 @@ static void tscInitLogFile() {
     printf("failed to create log dir:%s\n", tsLogDir);
   }
 
-  const char    *defaultLogFileNamePrefix = "taoslog";
-  const int32_t  maxLogFileNum = 10;
+  const char *  defaultLogFileNamePrefix = "taoslog";
+  const int32_t maxLogFileNum = 10;
 
   char temp[128] = {0};
   sprintf(temp, "%s/%s", tsLogDir, defaultLogFileNamePrefix);
@@ -90,23 +92,24 @@ static void tscInitLogFile() {
 }
 
 // todo close the transporter properly
-void closeTransporter(STscObj* pTscObj)  {
+void closeTransporter(STscObj *pTscObj) {
   if (pTscObj == NULL || pTscObj->pAppInfo->pTransporter == NULL) {
     return;
   }
 
-  tscDebug("free transporter:%p in connObj: 0x%"PRIx64, pTscObj->pAppInfo->pTransporter, pTscObj->id);
+  tscDebug("free transporter:%p in connObj: 0x%" PRIx64, pTscObj->pAppInfo->pTransporter, pTscObj->id);
   rpcClose(pTscObj->pAppInfo->pTransporter);
 }
 
 // TODO refactor
-void* openTransporter(const char *user, const char *auth, int32_t numOfThread) {
+void *openTransporter(const char *user, const char *auth, int32_t numOfThread) {
   SRpcInit rpcInit;
   memset(&rpcInit, 0, sizeof(rpcInit));
   rpcInit.localPort = 0;
   rpcInit.label = "TSC";
   rpcInit.numOfThreads = numOfThread;
   rpcInit.cfp = processMsgFromServer;
+  rpcInit.pfp = persistConnForSpecificMsg;
   rpcInit.sessions = tsMaxConnections;
   rpcInit.connType = TAOS_CONN_CLIENT;
   rpcInit.user = (char *)user;
@@ -115,7 +118,7 @@ void* openTransporter(const char *user, const char *auth, int32_t numOfThread) {
   rpcInit.spi = 1;
   rpcInit.secret = (char *)auth;
 
-  void* pDnodeConn = rpcOpen(&rpcInit);
+  void *pDnodeConn = rpcOpen(&rpcInit);
   if (pDnodeConn == NULL) {
     tscError("failed to init connection to server");
     return NULL;
@@ -130,12 +133,12 @@ void destroyTscObj(void *pObj) {
   SClientHbKey connKey = {.connId = pTscObj->connId, .hbType = pTscObj->connType};
   hbDeregisterConn(pTscObj->pAppInfo->pAppHbMgr, connKey);
   atomic_sub_fetch_64(&pTscObj->pAppInfo->numOfConns, 1);
-  tscDebug("connObj 0x%"PRIx64" destroyed, totalConn:%"PRId64, pTscObj->id, pTscObj->pAppInfo->numOfConns);
+  tscDebug("connObj 0x%" PRIx64 " destroyed, totalConn:%" PRId64, pTscObj->id, pTscObj->pAppInfo->numOfConns);
   pthread_mutex_destroy(&pTscObj->mutex);
   tfree(pTscObj);
 }
 
-void* createTscObj(const char* user, const char* auth, const char *db, SAppInstInfo* pAppInfo) {
+void *createTscObj(const char *user, const char *auth, const char *db, SAppInstInfo *pAppInfo) {
   STscObj *pObj = (STscObj *)calloc(1, sizeof(STscObj));
   if (NULL == pObj) {
     terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
@@ -153,11 +156,11 @@ void* createTscObj(const char* user, const char* auth, const char *db, SAppInstI
   pthread_mutex_init(&pObj->mutex, NULL);
   pObj->id = taosAddRef(clientConnRefPool, pObj);
 
-  tscDebug("connObj created, 0x%"PRIx64, pObj->id);
+  tscDebug("connObj created, 0x%" PRIx64, pObj->id);
   return pObj;
 }
 
-void* createRequest(STscObj* pObj, __taos_async_fn_t fp, void* param, int32_t type) {
+void *createRequest(STscObj *pObj, __taos_async_fn_t fp, void *param, int32_t type) {
   assert(pObj != NULL);
 
   SRequestObj *pRequest = (SRequestObj *)calloc(1, sizeof(SRequestObj));
@@ -166,20 +169,20 @@ void* createRequest(STscObj* pObj, __taos_async_fn_t fp, void* param, int32_t ty
     return NULL;
   }
 
-  pRequest->requestId  = generateRequestId();
+  pRequest->requestId = generateRequestId();
   pRequest->metric.start = taosGetTimestampMs();
 
-  pRequest->type       = type;
-  pRequest->pTscObj    = pObj;
-  pRequest->body.fp    = fp;    // not used it yet
-  pRequest->msgBuf     = calloc(1, ERROR_MSG_BUF_DEFAULT_SIZE);
+  pRequest->type = type;
+  pRequest->pTscObj = pObj;
+  pRequest->body.fp = fp;  // not used it yet
+  pRequest->msgBuf = calloc(1, ERROR_MSG_BUF_DEFAULT_SIZE);
   tsem_init(&pRequest->body.rspSem, 0, 0);
 
   registerRequest(pRequest);
   return pRequest;
 }
 
-static void doFreeReqResultInfo(SReqResultInfo* pResInfo) {
+static void doFreeReqResultInfo(SReqResultInfo *pResInfo) {
   tfree(pResInfo->pRspMsg);
   tfree(pResInfo->length);
   tfree(pResInfo->row);
@@ -187,9 +190,9 @@ static void doFreeReqResultInfo(SReqResultInfo* pResInfo) {
   tfree(pResInfo->fields);
 }
 
-static void doDestroyRequest(void* p) {
+static void doDestroyRequest(void *p) {
   assert(p != NULL);
-  SRequestObj* pRequest = (SRequestObj*)p;
+  SRequestObj *pRequest = (SRequestObj *)p;
 
   assert(RID_VALID(pRequest->self));
 
@@ -208,7 +211,7 @@ static void doDestroyRequest(void* p) {
   tfree(pRequest);
 }
 
-void destroyRequest(SRequestObj* pRequest) {
+void destroyRequest(SRequestObj *pRequest) {
   if (pRequest == NULL) {
     return;
   }
@@ -252,14 +255,14 @@ void taos_init_imp(void) {
   initTaskQueue();
 
   clientConnRefPool = taosOpenRef(200, destroyTscObj);
-  clientReqRefPool  = taosOpenRef(40960, doDestroyRequest);
+  clientReqRefPool = taosOpenRef(40960, doDestroyRequest);
 
   taosGetAppName(appInfo.appName, NULL);
   pthread_mutex_init(&appInfo.mutex, NULL);
 
-  appInfo.pid       = taosGetPId();
+  appInfo.pid = taosGetPId();
   appInfo.startTime = taosGetTimestampMs();
-  appInfo.pInstMap  = taosHashInit(4, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BINARY), true, HASH_ENTRY_LOCK);
+  appInfo.pInstMap = taosHashInit(4, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BINARY), true, HASH_ENTRY_LOCK);
   tscDebug("client is initialized successfully");
 }
 
@@ -281,7 +284,8 @@ int taos_options_imp(TSDB_OPTION option, const char *str) {
         cfg->cfgStatus = TAOS_CFG_CSTATUS_OPTION;
         tscInfo("set config file directory:%s", str);
       } else {
-        tscWarn("config option:%s, input value:%s, is configured by %s, use %s", cfg->option, str, tsCfgStatusStr[cfg->cfgStatus], (char *)cfg->ptr);
+        tscWarn("config option:%s, input value:%s, is configured by %s, use %s", cfg->option, str,
+                tsCfgStatusStr[cfg->cfgStatus], (char *)cfg->ptr);
       }
       break;
 
@@ -296,7 +300,8 @@ int taos_options_imp(TSDB_OPTION option, const char *str) {
         cfg->cfgStatus = TAOS_CFG_CSTATUS_OPTION;
         tscInfo("set shellActivityTimer:%d", tsShellActivityTimer);
       } else {
-        tscWarn("config option:%s, input value:%s, is configured by %s, use %d", cfg->option, str, tsCfgStatusStr[cfg->cfgStatus], *(int32_t *)cfg->ptr);
+        tscWarn("config option:%s, input value:%s, is configured by %s, use %d", cfg->option, str,
+                tsCfgStatusStr[cfg->cfgStatus], *(int32_t *)cfg->ptr);
       }
       break;
 
@@ -313,8 +318,8 @@ int taos_options_imp(TSDB_OPTION option, const char *str) {
       if (cfg->cfgStatus <= TAOS_CFG_CSTATUS_OPTION) {
         char sep = '.';
 
-        if (strlen(tsLocale) == 0) { // locale does not set yet
-          char* defaultLocale = setlocale(LC_CTYPE, "");
+        if (strlen(tsLocale) == 0) {  // locale does not set yet
+          char *defaultLocale = setlocale(LC_CTYPE, "");
 
           // The locale of the current OS does not be set correctly, so the default locale cannot be acquired.
           // The launch of current system will abort soon.
@@ -329,10 +334,10 @@ int taos_options_imp(TSDB_OPTION option, const char *str) {
         // set the user specified locale
         char *locale = setlocale(LC_CTYPE, str);
 
-        if (locale != NULL) { // failed to set the user specified locale
+        if (locale != NULL) {  // failed to set the user specified locale
           tscInfo("locale set, prev locale:%s, new locale:%s", tsLocale, locale);
           cfg->cfgStatus = TAOS_CFG_CSTATUS_OPTION;
-        } else { // set the user specified locale failed, use default LC_CTYPE as current locale
+        } else {  // set the user specified locale failed, use default LC_CTYPE as current locale
           locale = setlocale(LC_CTYPE, tsLocale);
           tscInfo("failed to set locale:%s, current locale:%s", str, tsLocale);
         }
@@ -360,11 +365,12 @@ int taos_options_imp(TSDB_OPTION option, const char *str) {
           }
 
           free(charset);
-        } else { // it may be windows system
+        } else {  // it may be windows system
           tscInfo("charset remains:%s", tsCharset);
         }
       } else {
-        tscWarn("config option:%s, input value:%s, is configured by %s, use %s", cfg->option, str, tsCfgStatusStr[cfg->cfgStatus], (char *)cfg->ptr);
+        tscWarn("config option:%s, input value:%s, is configured by %s, use %s", cfg->option, str,
+                tsCfgStatusStr[cfg->cfgStatus], (char *)cfg->ptr);
       }
       break;
     }
@@ -394,7 +400,8 @@ int taos_options_imp(TSDB_OPTION option, const char *str) {
           tscInfo("charset:%s not valid", str);
         }
       } else {
-        tscWarn("config option:%s, input value:%s, is configured by %s, use %s", cfg->option, str, tsCfgStatusStr[cfg->cfgStatus], (char *)cfg->ptr);
+        tscWarn("config option:%s, input value:%s, is configured by %s, use %s", cfg->option, str,
+                tsCfgStatusStr[cfg->cfgStatus], (char *)cfg->ptr);
       }
 
       break;
@@ -410,7 +417,8 @@ int taos_options_imp(TSDB_OPTION option, const char *str) {
         cfg->cfgStatus = TAOS_CFG_CSTATUS_OPTION;
         tscDebug("timezone set:%s, input:%s by taos_options", tsTimezone, str);
       } else {
-        tscWarn("config option:%s, input value:%s, is configured by %s, use %s", cfg->option, str, tsCfgStatusStr[cfg->cfgStatus], (char *)cfg->ptr);
+        tscWarn("config option:%s, input value:%s, is configured by %s, use %s", cfg->option, str,
+                tsCfgStatusStr[cfg->cfgStatus], (char *)cfg->ptr);
       }
       break;
 
@@ -434,7 +442,7 @@ int taos_options_imp(TSDB_OPTION option, const char *str) {
  */
 uint64_t generateRequestId() {
   static uint64_t hashId = 0;
-  static int32_t requestSerialId = 0;
+  static int32_t  requestSerialId = 0;
 
   if (hashId == 0) {
     char    uid[64] = {0};
@@ -448,9 +456,9 @@ uint64_t generateRequestId() {
     }
   }
 
-  int64_t ts      = taosGetTimestampMs();
-  uint64_t pid    = taosGetPId();
-  int32_t val     = atomic_add_fetch_32(&requestSerialId, 1);
+  int64_t  ts = taosGetTimestampMs();
+  uint64_t pid = taosGetPId();
+  int32_t  val = atomic_add_fetch_32(&requestSerialId, 1);
 
   uint64_t id = ((hashId & 0x0FFF) << 52) | ((pid & 0x0FFF) << 40) | ((ts & 0xFFFFFF) << 16) | (val & 0xFFFF);
   return id;
diff --git a/source/client/src/clientImpl.c b/source/client/src/clientImpl.c
index 2eff353c3947d2fa7f908300b79feadd0c75f93c..3b35b6bdd4bbdb6bc483f14dfc19d6cc0098dc5b 100644
--- a/source/client/src/clientImpl.c
+++ b/source/client/src/clientImpl.c
@@ -370,7 +370,6 @@ static SMsgSendInfo* buildConnectMsg(SRequestObj* pRequest) {
   pMsgSendInfo->fp = handleRequestRspFp[TMSG_INDEX(pMsgSendInfo->msgType)];
   pMsgSendInfo->param = pRequest;
 
-
   SConnectReq connectReq = {0};
   STscObj*    pObj = pRequest->pTscObj;
 
@@ -398,7 +397,9 @@ static void destroySendMsgInfo(SMsgSendInfo* pMsgBody) {
   tfree(pMsgBody->msgInfo.pData);
   tfree(pMsgBody);
 }
-
+bool persistConnForSpecificMsg(void* parenct, tmsg_t msgType) {
+  return msgType == TDMT_VND_QUERY_RSP || msgType == TDMT_VND_FETCH_RSP || msgType == TDMT_VND_RES_READY_RSP;
+}
 void processMsgFromServer(void* parent, SRpcMsg* pMsg, SEpSet* pEpSet) {
   SMsgSendInfo* pSendInfo = (SMsgSendInfo*)pMsg->ahandle;
   assert(pMsg->ahandle != NULL);
diff --git a/source/libs/transport/inc/transportInt.h b/source/libs/transport/inc/transportInt.h
index a36b671eb459268c1fcf51ca80ac21a88d050e37..d080db753d525362ecd8cca464f17f6d80fbd19e 100644
--- a/source/libs/transport/inc/transportInt.h
+++ b/source/libs/transport/inc/transportInt.h
@@ -66,6 +66,7 @@ typedef struct {
 
   void (*cfp)(void* parent, SRpcMsg*, SEpSet*);
   int (*afp)(void* parent, char* user, char* spi, char* encrypt, char* secret, char* ckey);
+  bool (*pfp)(void* parent, tmsg_t msgType);
 
   int32_t         refCount;
   void*           parent;
diff --git a/source/libs/transport/src/trans.c b/source/libs/transport/src/trans.c
index 48c15ca286e6202be5d71ca7791272b0a07ce3f3..453b5184d2c3d19ac388dd971af8894a9ed01135 100644
--- a/source/libs/transport/src/trans.c
+++ b/source/libs/transport/src/trans.c
@@ -29,7 +29,12 @@ void* rpcOpen(const SRpcInit* pInit) {
   if (pInit->label) {
     tstrncpy(pRpc->label, pInit->label, strlen(pInit->label) + 1);
   }
+
+  // register callback handle
   pRpc->cfp = pInit->cfp;
+  pRpc->afp = pInit->afp;
+  pRpc->pfp = pInit->pfp;
+
   if (pInit->connType == TAOS_CONN_SERVER) {
     pRpc->numOfThreads = pInit->numOfThreads > TSDB_MAX_RPC_THREADS ? TSDB_MAX_RPC_THREADS : pInit->numOfThreads;
   } else {
diff --git a/source/libs/transport/src/transCli.c b/source/libs/transport/src/transCli.c
index 8312c0217c13d40a43b57c82dc22ff04d5ddcd65..d5fa4c8c479494b82d97224af013f9b30cf0e961 100644
--- a/source/libs/transport/src/transCli.c
+++ b/source/libs/transport/src/transCli.c
@@ -134,8 +134,7 @@ static void clientHandleResp(SCliConn* conn) {
   rpcMsg.msgType = pHead->msgType;
   rpcMsg.ahandle = pCtx->ahandle;
 
-  if (rpcMsg.msgType == TDMT_VND_QUERY_RSP || rpcMsg.msgType == TDMT_VND_FETCH_RSP ||
-      rpcMsg.msgType == TDMT_VND_RES_READY_RSP) {
+  if (pRpc->pfp != NULL && (pRpc->pfp)(pRpc->parent, rpcMsg.msgType)) {
     rpcMsg.handle = conn;
     conn->persist = 1;
     tDebug("client conn %p persist by app", conn);
@@ -185,18 +184,13 @@ static void clientHandleExcept(SCliConn* pConn) {
     clientConnDestroy(pConn, true);
     return;
   }
-  SCliMsg* pMsg = pConn->data;
-
-  tmsg_t msgType = TDMT_MND_CONNECT;
-  if (pMsg != NULL) {
-    msgType = pMsg->msg.msgType;
-  }
+  SCliMsg*       pMsg = pConn->data;
   STransConnCtx* pCtx = pMsg->ctx;
 
   SRpcMsg rpcMsg = {0};
   rpcMsg.ahandle = pCtx->ahandle;
   rpcMsg.code = TSDB_CODE_RPC_NETWORK_UNAVAIL;
-  rpcMsg.msgType = msgType + 1;
+  rpcMsg.msgType = pMsg->msg.msgType + 1;
 
   if (pConn->push != NULL && pConn->ctnRdCnt != 0) {
     (*pConn->push->callback)(pConn->push->arg, &rpcMsg);
@@ -445,7 +439,7 @@ static void clientConnCb(uv_connect_t* req, int status) {
   addrlen = sizeof(pConn->locaddr);
   uv_tcp_getsockname((uv_tcp_t*)pConn->stream, (struct sockaddr*)&pConn->locaddr, &addrlen);
 
-  tTrace("client conn %p create", pConn);
+  tTrace("client conn %p connect to server successfully", pConn);
 
   assert(pConn->stream == req->handle);
   clientWrite(pConn);
@@ -524,6 +518,7 @@ static void clientHandleReq(SCliMsg* pMsg, SCliThrdObj* pThrd) {
     struct sockaddr_in addr;
     uv_ip4_addr(pMsg->ctx->ip, pMsg->ctx->port, &addr);
     // handle error in callback if fail to connect
+    tTrace("client conn %p try to connect to %s:%d", conn, pMsg->ctx->ip, pMsg->ctx->port);
     uv_tcp_connect(&conn->connReq, (uv_tcp_t*)(conn->stream), (const struct sockaddr*)&addr, clientConnCb);
   }
 
diff --git a/source/libs/transport/src/transSrv.c b/source/libs/transport/src/transSrv.c
index 9fca371bf30588f7bdd50f5a3cc452e000bd03eb..f0db054797b936b8fde9fa3b241c8dbff909bb90 100644
--- a/source/libs/transport/src/transSrv.c
+++ b/source/libs/transport/src/transSrv.c
@@ -413,11 +413,6 @@ void uvWorkerAsyncCb(uv_async_t* handle) {
     } else {
       uvStartSendResp(msg);
     }
-    // uv_buf_t wb;
-    // uvPrepareSendData(msg, &wb);
-    // uv_timer_stop(conn->pTimer);
-
-    // uv_write(conn->pWriter, (uv_stream_t*)conn->pTcp, &wb, 1, uvOnWriteCb);
   }
 }
 static void uvAcceptAsyncCb(uv_async_t* async) {
@@ -490,7 +485,6 @@ void uvOnConnectionCb(uv_stream_t* q, ssize_t nread, const uv_buf_t* buf) {
   pConn->pTimer->data = pConn;
 
   pConn->hostThrd = pThrd;
-  // pConn->pWorkerAsync = pThrd->workerAsync;  // thread safty
 
   // init client handle
   pConn->pTcp = (uv_tcp_t*)malloc(sizeof(uv_tcp_t));
@@ -730,14 +724,9 @@ void destroyWorkThrd(SWorkThrdObj* pThrd) {
 }
 void sendQuitToWorkThrd(SWorkThrdObj* pThrd) {
   SSrvMsg* srvMsg = calloc(1, sizeof(SSrvMsg));
-
-  // pthread_mutex_lock(&pThrd->msgMtx);
-  // QUEUE_PUSH(&pThrd->msg, &srvMsg->q);
-  // pthread_mutex_unlock(&pThrd->msgMtx);
   tDebug("send quit msg to work thread");
 
   transSendAsync(pThrd->asyncPool, &srvMsg->q);
-  // uv_async_send(pThrd->workerAsync);
 }
 
 void taosCloseServer(void* arg) {
@@ -774,19 +763,12 @@ void rpcSendResponse(const SRpcMsg* pMsg) {
   SSrvMsg* srvMsg = calloc(1, sizeof(SSrvMsg));
   srvMsg->pConn = pConn;
   srvMsg->msg = *pMsg;
-
-  // pthread_mutex_lock(&pThrd->msgMtx);
-  // QUEUE_PUSH(&pThrd->msg, &srvMsg->q);
-  // pthread_mutex_unlock(&pThrd->msgMtx);
-
   tTrace("server conn %p start to send resp", pConn);
   transSendAsync(pThrd->asyncPool, &srvMsg->q);
-  // uv_async_send(pThrd->workerAsync);
 }
 
 int rpcGetConnInfo(void* thandle, SRpcConnInfo* pInfo) {
   SSrvConn* pConn = thandle;
-  // struct sockaddr* pPeerName = &pConn->peername;
 
   struct sockaddr_in addr = pConn->addr;
   pInfo->clientIp = (uint32_t)(addr.sin_addr.s_addr);