diff --git a/include/libs/transport/trpc.h b/include/libs/transport/trpc.h
index 8dfd736df6..b5b8d6ab66 100644
--- a/include/libs/transport/trpc.h
+++ b/include/libs/transport/trpc.h
@@ -29,7 +29,6 @@ extern "C" {
 
 extern int tsRpcHeadSize;
 
-
 typedef struct SRpcConnInfo {
   uint32_t clientIp;
   uint16_t clientPort;
@@ -46,7 +45,6 @@ typedef struct SRpcMsg {
   void *  ahandle;  // app handle set by client
 } SRpcMsg;
 
-
 typedef struct SRpcInit {
   uint16_t localPort;     // local port
   char *   label;         // for debug purpose
@@ -71,9 +69,11 @@ typedef struct SRpcInit {
   // call back to keep conn or not
   bool (*pfp)(void *parent, tmsg_t msgType);
 
-  // to support Send messages multiple times on a link  
-  // 
-  void* (*mfp)(void *parent, tmsg_t msgType);
+  // to support Send messages multiple times on a link
+  void *(*mfp)(void *parent, tmsg_t msgType);
+
+  // call back  to handle except when query/fetch in progress
+  void (*efp)(void *parent, tmsg_t msgType);
 
   void *parent;
 } SRpcInit;
@@ -94,7 +94,7 @@ int     rpcReportProgress(void *pConn, char *pCont, int contLen);
 void    rpcCancelRequest(int64_t rid);
 
 // just release client conn to rpc instance, no close sock
-void rpcReleaseHandle(void *handle);   
+void rpcReleaseHandle(void *handle, int8_t type);
 
 void rpcRefHandle(void *handle, int8_t type);
 void rpcUnrefHandle(void *handle, int8_t type);
diff --git a/source/libs/transport/inc/transComm.h b/source/libs/transport/inc/transComm.h
index 99f890d3a0..8ea65b193d 100644
--- a/source/libs/transport/inc/transComm.h
+++ b/source/libs/transport/inc/transComm.h
@@ -125,9 +125,8 @@ typedef SRpcInfo     STrans;
 typedef SRpcConnInfo STransHandleInfo;
 
 typedef struct {
-  SEpSet epSet;    // ip list provided by app
-  void*  ahandle;  // handle provided by app
-  // struct SRpcConn* pConn;     // pConn allocated
+  SEpSet   epSet;    // ip list provided by app
+  void*    ahandle;  // handle provided by app
   tmsg_t   msgType;  // message type
   uint8_t* pCont;    // content provided by app
   int32_t  contLen;  // content length
@@ -135,7 +134,7 @@ typedef struct {
   // int16_t  numOfTry;  // number of try for different servers
   // int8_t   oldInUse;  // server EP inUse passed by app
   // int8_t   redirect;  // flag to indicate redirect
-  int8_t  connType;  // connection type
+  int8_t  connType;  // connection type cli/srv
   int64_t rid;       // refId returned by taosAddRef
 
   STransMsg* pRsp;  // for synchronous API
@@ -253,6 +252,9 @@ void transUnrefSrvHandle(void* handle);
 void transRefCliHandle(void* handle);
 void transUnrefCliHandle(void* handle);
 
+void transReleaseCliHandle(void* handle);
+void transReleaseSrvHandle(void* handle);
+
 void transSendRequest(void* shandle, const char* ip, uint32_t port, STransMsg* pMsg);
 void transSendRecv(void* shandle, const char* ip, uint32_t port, STransMsg* pMsg, STransMsg* pRsp);
 void transSendResponse(const STransMsg* pMsg);
diff --git a/source/libs/transport/inc/transportInt.h b/source/libs/transport/inc/transportInt.h
index 3924a5cf1a..e760fe1de9 100644
--- a/source/libs/transport/inc/transportInt.h
+++ b/source/libs/transport/inc/transportInt.h
@@ -65,6 +65,7 @@ typedef struct {
   int (*afp)(void* parent, char* user, char* spi, char* encrypt, char* secret, char* ckey);
   bool (*pfp)(void* parent, tmsg_t msgType);
   void* (*mfp)(void* parent, tmsg_t msgType);
+  void (*efp)(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 58809ee3be..2cab03f133 100644
--- a/source/libs/transport/src/trans.c
+++ b/source/libs/transport/src/trans.c
@@ -22,6 +22,11 @@ void* (*taosInitHandle[])(uint32_t ip, uint32_t port, char* label, int numOfThre
 
 void (*taosCloseHandle[])(void* arg) = {transCloseServer, transCloseClient};
 
+void (*taosRefHandle[])(void* handle) = {transRefSrvHandle, transRefCliHandle};
+void (*taosUnRefHandle[])(void* handle) = {transUnrefSrvHandle, transUnrefCliHandle};
+
+void (*transReleaseHandle[])(void* handle) = {transReleaseSrvHandle, transReleaseCliHandle};
+
 void* rpcOpen(const SRpcInit* pInit) {
   SRpcInfo* pRpc = calloc(1, sizeof(SRpcInfo));
   if (pRpc == NULL) {
@@ -36,6 +41,7 @@ void* rpcOpen(const SRpcInit* pInit) {
   pRpc->afp = pInit->afp;
   pRpc->pfp = pInit->pfp;
   pRpc->mfp = pInit->mfp;
+  pRpc->efp = pInit->efp;
 
   if (pInit->connType == TAOS_CONN_SERVER) {
     pRpc->numOfThreads = pInit->numOfThreads > TSDB_MAX_RPC_THREADS ? TSDB_MAX_RPC_THREADS : pInit->numOfThreads;
@@ -126,9 +132,6 @@ void rpcSendRecv(void* shandle, SEpSet* pEpSet, SRpcMsg* pMsg, SRpcMsg* pRsp) {
 void rpcSendResponse(const SRpcMsg* pMsg) { transSendResponse(pMsg); }
 int  rpcGetConnInfo(void* thandle, SRpcConnInfo* pInfo) { return transGetConnInfo((void*)thandle, pInfo); }
 
-void (*taosRefHandle[])(void* handle) = {transRefSrvHandle, transRefCliHandle};
-void (*taosUnRefHandle[])(void* handle) = {transUnrefSrvHandle, transUnrefCliHandle};
-
 void rpcRefHandle(void* handle, int8_t type) {
   assert(type == TAOS_CONN_SERVER || type == TAOS_CONN_CLIENT);
   (*taosRefHandle[type])(handle);
@@ -139,6 +142,11 @@ void rpcUnrefHandle(void* handle, int8_t type) {
   (*taosUnRefHandle[type])(handle);
 }
 
+void rpcReleaseHandle(void* handle, int8_t type) {
+  assert(type == TAOS_CONN_SERVER || type == TAOS_CONN_CLIENT);
+  (*transReleaseHandle[type])(handle);
+}
+
 int32_t rpcInit() {
   // impl later
   return 0;
diff --git a/source/libs/transport/src/transCli.c b/source/libs/transport/src/transCli.c
index 5be1b7ea90..b7bc428901 100644
--- a/source/libs/transport/src/transCli.c
+++ b/source/libs/transport/src/transCli.c
@@ -17,6 +17,11 @@
 
 #include "transComm.h"
 
+// Normal(default):   send/recv msg
+// Quit:     quit rpc inst
+// Release:  release handle to rpc inst
+typedef enum { Normal, Quit, Release } SCliMsgType;
+
 typedef struct SCliConn {
   T_REF_DECLARE()
   uv_connect_t connReq;
@@ -34,6 +39,10 @@ typedef struct SCliConn {
   // spi configure
   char spi;
   char secured;
+
+  char*    ip;
+  uint32_t port;
+
   // debug and log info
   struct sockaddr_in addr;
   struct sockaddr_in locaddr;
@@ -45,6 +54,7 @@ typedef struct SCliMsg {
   STransMsg      msg;
   queue          q;
   uint64_t       st;
+  SCliMsgType    type;
 } SCliMsg;
 
 typedef struct SCliThrdObj {
@@ -79,7 +89,7 @@ typedef struct SConnList {
 static void*     createConnPool(int size);
 static void*     destroyConnPool(void* pool);
 static SCliConn* getConnFromPool(void* pool, char* ip, uint32_t port);
-static void      addConnToPool(void* pool, char* ip, uint32_t port, SCliConn* conn);
+static void      addConnToPool(void* pool, SCliConn* conn);
 
 // register timer in each thread to clear expire conn
 static void cliTimeoutCb(uv_timer_t* handle);
@@ -104,6 +114,8 @@ static void cliHandleExcept(SCliConn* conn);
 // handle req from app
 static void cliHandleReq(SCliMsg* pMsg, SCliThrdObj* pThrd);
 static void cliHandleQuit(SCliMsg* pMsg, SCliThrdObj* pThrd);
+static void cliHandleRelease(SCliMsg* pMsg, SCliThrdObj* pThrd);
+
 static void cliSendQuit(SCliThrdObj* thrd);
 static void destroyUserdata(STransMsg* userdata);
 
@@ -117,8 +129,8 @@ static void         destroyThrdObj(SCliThrdObj* pThrd);
 
 #define CONN_HOST_THREAD_INDEX(conn) (conn ? ((SCliConn*)conn)->hThrdIdx : -1)
 #define CONN_PERSIST_TIME(para) (para * 1000 * 10)
-
-#define CONN_GET_INST_LABEL(conn) (((STrans*)(((SCliThrdObj*)conn->hostThrd)->pTransInst))->label)
+#define CONN_GET_HOST_THREAD(conn) (conn ? ((SCliConn*)conn)->hostThrd : NULL)
+#define CONN_GET_INST_LABEL(conn) (((STrans*)(((SCliThrdObj*)(conn)->hostThrd)->pTransInst))->label)
 #define CONN_HANDLE_THREAD_QUIT(conn, thrd) \
   do {                                      \
     if (thrd->quit) {                       \
@@ -188,6 +200,12 @@ void cliHandleResp(SCliConn* conn) {
 
   conn->secured = pHead->secured;
 
+  if (pCtx == NULL && CONN_NO_PERSIST_BY_APP(conn)) {
+    tTrace("except, server continue send while cli ignore it");
+    // transUnrefCliHandle(conn);
+    return;
+  }
+
   if (pCtx == NULL || pCtx->pSem == NULL) {
     tTrace("%s cli conn %p handle resp", pTransInst->label, conn);
     (pTransInst->cfp)(pTransInst->parent, &transMsg, NULL);
@@ -197,14 +215,13 @@ void cliHandleResp(SCliConn* conn) {
     tsem_post(pCtx->pSem);
   }
 
-  uv_read_start((uv_stream_t*)conn->stream, cliAllocRecvBufferCb, cliRecvCb);
-
   if (CONN_NO_PERSIST_BY_APP(conn)) {
-    addConnToPool(pThrd->pool, pCtx->ip, pCtx->port, conn);
+    addConnToPool(pThrd->pool, conn);
   }
   destroyCmsg(conn->data);
   conn->data = NULL;
 
+  uv_read_start((uv_stream_t*)conn->stream, cliAllocRecvBufferCb, cliRecvCb);
   // start thread's timer of conn pool if not active
   if (!uv_is_active((uv_handle_t*)&pThrd->timer) && pTransInst->idleTime > 0) {
     // uv_timer_start((uv_timer_t*)&pThrd->timer, cliTimeoutCb, CONN_PERSIST_TIME(pRpc->idleTime) / 2, 0);
@@ -318,11 +335,11 @@ static SCliConn* getConnFromPool(void* pool, char* ip, uint32_t port) {
   QUEUE_INIT(&conn->conn);
   return conn;
 }
-static void addConnToPool(void* pool, char* ip, uint32_t port, SCliConn* conn) {
+static void addConnToPool(void* pool, SCliConn* conn) {
   char key[128] = {0};
 
-  tstrncpy(key, ip, strlen(ip));
-  tstrncpy(key + strlen(key), (char*)(&port), sizeof(port));
+  tstrncpy(key, conn->ip, strlen(conn->ip));
+  tstrncpy(key + strlen(key), (char*)(&conn->port), sizeof(conn->port));
   tTrace("cli conn %p added to conn pool, read buf cap: %d", conn, conn->readBuf.cap);
 
   STrans* pTransInst = ((SCliThrdObj*)conn->hostThrd)->pTransInst;
@@ -336,6 +353,8 @@ static void addConnToPool(void* pool, char* ip, uint32_t port, SCliConn* conn) {
 static void cliAllocRecvBufferCb(uv_handle_t* handle, size_t suggested_size, uv_buf_t* buf) {
   SCliConn*    conn = handle->data;
   SConnBuffer* pBuf = &conn->readBuf;
+  // avoid conn
+  QUEUE_REMOVE(&conn->conn);
   transAllocBuffer(pBuf, buf);
 }
 static void cliRecvCb(uv_stream_t* handle, ssize_t nread, const uv_buf_t* buf) {
@@ -396,7 +415,7 @@ static void cliDestroyConn(SCliConn* conn, bool clear) {
 }
 static void cliDestroy(uv_handle_t* handle) {
   SCliConn* conn = handle->data;
-
+  free(conn->ip);
   free(conn->stream);
   tTrace("%s cli conn %p destroy successfully", CONN_GET_INST_LABEL(conn), conn);
   free(conn);
@@ -498,6 +517,22 @@ static void cliHandleQuit(SCliMsg* pMsg, SCliThrdObj* pThrd) {
   pThrd->quit = true;
   uv_stop(pThrd->loop);
 }
+static void cliHandleRelease(SCliMsg* pMsg, SCliThrdObj* pThrd) {
+  SCliConn* conn = pMsg->msg.handle;
+  tDebug("%s cli conn %p release to inst", CONN_GET_INST_LABEL(conn), conn);
+
+  destroyCmsg(pMsg);
+  conn->data = NULL;
+
+  transDestroyBuffer(&conn->readBuf);
+  if (conn->persist && T_REF_VAL_GET(conn) >= 2) {
+    conn->persist = false;
+    transUnrefCliHandle(conn);
+    addConnToPool(pThrd->pool, conn);
+  } else {
+    transUnrefCliHandle(conn);
+  }
+}
 
 SCliConn* cliGetConn(SCliMsg* pMsg, SCliThrdObj* pThrd) {
   SCliConn* conn = NULL;
@@ -509,7 +544,9 @@ SCliConn* cliGetConn(SCliMsg* pMsg, SCliThrdObj* pThrd) {
   } else {
     STransConnCtx* pCtx = pMsg->ctx;
     conn = getConnFromPool(pThrd->pool, pCtx->ip, pCtx->port);
-    if (conn != NULL) tTrace("%s cli conn %p get from conn pool", CONN_GET_INST_LABEL(conn), conn);
+    if (conn != NULL) {
+      tTrace("%s cli conn %p get from conn pool", CONN_GET_INST_LABEL(conn), conn);
+    }
   }
   return conn;
 }
@@ -525,11 +562,16 @@ void cliHandleReq(SCliMsg* pMsg, SCliThrdObj* pThrd) {
   SCliConn* conn = cliGetConn(pMsg, pThrd);
   if (conn != NULL) {
     conn->data = pMsg;
+    conn->hThrdIdx = pCtx->hThrdIdx;
+
     transDestroyBuffer(&conn->readBuf);
     cliSend(conn);
   } else {
     conn = cliCreateConn(pThrd);
     conn->data = pMsg;
+    conn->hThrdIdx = pCtx->hThrdIdx;
+    conn->ip = strdup(pMsg->ctx->ip);
+    conn->port = pMsg->ctx->port;
 
     int ret = transSetConnOption((uv_tcp_t*)conn->stream);
     if (ret) {
@@ -541,8 +583,6 @@ void cliHandleReq(SCliMsg* pMsg, SCliThrdObj* pThrd) {
     tTrace("%s cli conn %p try to connect to %s:%d", pTransInst->label, conn, pMsg->ctx->ip, pMsg->ctx->port);
     uv_tcp_connect(&conn->connReq, (uv_tcp_t*)(conn->stream), (const struct sockaddr*)&addr, cliConnCb);
   }
-
-  conn->hThrdIdx = pCtx->hThrdIdx;
 }
 static void cliAsyncCb(uv_async_t* handle) {
   SAsyncItem*  item = handle->data;
@@ -561,10 +601,13 @@ static void cliAsyncCb(uv_async_t* handle) {
     QUEUE_REMOVE(h);
 
     SCliMsg* pMsg = QUEUE_DATA(h, SCliMsg, q);
-    if (pMsg->ctx == NULL) {
-      cliHandleQuit(pMsg, pThrd);
-    } else {
+
+    if (pMsg->type == Normal) {
       cliHandleReq(pMsg, pThrd);
+    } else if (pMsg->type == Quit) {
+      cliHandleQuit(pMsg, pThrd);
+    } else if (pMsg->type == Release) {
+      cliHandleRelease(pMsg, pThrd);
     }
     count++;
   }
@@ -662,8 +705,10 @@ static void transDestroyConnCtx(STransConnCtx* ctx) {
 void cliSendQuit(SCliThrdObj* thrd) {
   // cli can stop gracefully
   SCliMsg* msg = calloc(1, sizeof(SCliMsg));
+  msg->type = Quit;
   transSendAsync(thrd->asyncPool, &msg->q);
 }
+
 int cliRBChoseIdx(STrans* pTransInst) {
   int64_t index = pTransInst->index;
   if (pTransInst->index++ >= pTransInst->numOfThreads) {
@@ -693,10 +738,24 @@ void transUnrefCliHandle(void* handle) {
     return;
   }
   int ref = T_REF_DEC((SCliConn*)handle);
+  tDebug("%s cli conn %p ref %d", CONN_GET_INST_LABEL((SCliConn*)handle), handle, ref);
   if (ref == 0) {
     cliDestroyConn((SCliConn*)handle, true);
   }
 }
+void transReleaseCliHandle(void* handle) {
+  SCliThrdObj* thrd = CONN_GET_HOST_THREAD(handle);
+  if (thrd == NULL) {
+    return;
+  }
+
+  STransMsg tmsg = {.handle = handle};
+  SCliMsg*  cmsg = calloc(1, sizeof(SCliMsg));
+  cmsg->type = Release;
+  cmsg->msg = tmsg;
+
+  transSendAsync(thrd->asyncPool, &cmsg->q);
+}
 
 void transSendRequest(void* shandle, const char* ip, uint32_t port, STransMsg* pMsg) {
   STrans* pTransInst = (STrans*)shandle;
@@ -719,7 +778,7 @@ void transSendRequest(void* shandle, const char* ip, uint32_t port, STransMsg* p
   assert(pTransInst->connType == TAOS_CONN_CLIENT);
   // atomic or not
 
-  SCliMsg* cliMsg = malloc(sizeof(SCliMsg));
+  SCliMsg* cliMsg = calloc(1, sizeof(SCliMsg));
   cliMsg->ctx = pCtx;
   cliMsg->msg = *pMsg;
   cliMsg->st = taosGetTimestampUs();
@@ -744,7 +803,7 @@ void transSendRecv(void* shandle, const char* ip, uint32_t port, STransMsg* pReq
   pCtx->pRsp = pRsp;
   tsem_init(pCtx->pSem, 0, 0);
 
-  SCliMsg* cliMsg = malloc(sizeof(SCliMsg));
+  SCliMsg* cliMsg = calloc(1, sizeof(SCliMsg));
   cliMsg->ctx = pCtx;
   cliMsg->msg = *pReq;
   cliMsg->st = taosGetTimestampUs();
diff --git a/source/libs/transport/src/transSrv.c b/source/libs/transport/src/transSrv.c
index d26c5ec0f4..c1fbb50590 100644
--- a/source/libs/transport/src/transSrv.c
+++ b/source/libs/transport/src/transSrv.c
@@ -289,11 +289,13 @@ void uvOnSendCb(uv_write_t* req, int status) {
     if (conn->srvMsgs != NULL) {
       assert(taosArrayGetSize(conn->srvMsgs) >= 1);
       SSrvMsg* msg = taosArrayGetP(conn->srvMsgs, 0);
+      tTrace("server conn %p sending msg size: %d", conn, (int)taosArrayGetSize(conn->srvMsgs));
       taosArrayRemove(conn->srvMsgs, 0);
       destroySmsg(msg);
 
       // send second data, just use for push
       if (taosArrayGetSize(conn->srvMsgs) > 0) {
+        tTrace("resent server conn %p sending msg size: %d", conn, (int)taosArrayGetSize(conn->srvMsgs));
         msg = (SSrvMsg*)taosArrayGetP(conn->srvMsgs, 0);
         uvStartSendRespInternal(msg);
       }
@@ -643,7 +645,7 @@ static void uvDestroyConn(uv_handle_t* handle) {
   uv_timer_stop(&conn->pTimer);
   QUEUE_REMOVE(&conn->queue);
   free(conn->pTcp);
-  free(conn);
+  // free(conn);
 
   if (thrd->quit && QUEUE_IS_EMPTY(&thrd->conn)) {
     uv_loop_close(thrd->loop);
@@ -737,7 +739,7 @@ void destroyWorkThrd(SWorkThrdObj* pThrd) {
 }
 void sendQuitToWorkThrd(SWorkThrdObj* pThrd) {
   SSrvMsg* srvMsg = calloc(1, sizeof(SSrvMsg));
-  tDebug("send quit msg to work thread");
+  tDebug("server send quit msg to work thread");
 
   transSendAsync(pThrd->asyncPool, &srvMsg->q);
 }
@@ -788,6 +790,11 @@ void transUnrefSrvHandle(void* handle) {
   }
   // unref srv handle
 }
+
+void transReleaseSrvHandle(void* handle) {
+  // do nothing currently
+  //
+}
 void transSendResponse(const STransMsg* pMsg) {
   if (pMsg->handle == NULL) {
     return;
diff --git a/source/libs/transport/test/transUT.cc b/source/libs/transport/test/transUT.cc
index fa20327003..46f6424b0b 100644
--- a/source/libs/transport/test/transUT.cc
+++ b/source/libs/transport/test/transUT.cc
@@ -29,7 +29,29 @@ const char *ckey = "ckey";
 class Server;
 int port = 7000;
 // server process
+
+static bool cliPersistHandle(void *parent, tmsg_t msgType) {
+  // client persist handle
+  return msgType == 2 || msgType == 4;
+}
+
+typedef struct CbArgs {
+  tmsg_t msgType;
+} CbArgs;
+
+static void *ConstructArgForSpecificMsgType(void *parent, tmsg_t msgType) {
+  if (msgType == 1 || msgType == 2) {
+    CbArgs *args = (CbArgs *)calloc(1, sizeof(CbArgs));
+    args->msgType = msgType;
+    return args;
+  }
+  return NULL;
+}
+// server except
+static void NotifyAppLinkBroken(void *parent, tmsg_t msgType) {}
 typedef void (*CB)(void *parent, SRpcMsg *pMsg, SEpSet *pEpSet);
+
+static void processContinueSend(void *parent, SRpcMsg *pMsg, SEpSet *pEpSet);
 static void processReq(void *parent, SRpcMsg *pMsg, SEpSet *pEpSet);
 // client process;
 static void processResp(void *parent, SRpcMsg *pMsg, SEpSet *pEpSet);
@@ -61,17 +83,17 @@ class Client {
     rpcInit_.cfp = cb;
     this->transCli = rpcOpen(&rpcInit_);
   }
-  void setPersistFP(bool (*pfp)(void *parent, tmsg_t msgType)) {
+  void SetPersistFP(bool (*pfp)(void *parent, tmsg_t msgType)) {
     rpcClose(this->transCli);
     rpcInit_.pfp = pfp;
     this->transCli = rpcOpen(&rpcInit_);
   }
-  void setConstructFP(void *(*mfp)(void *parent, tmsg_t msgType)) {
+  void SetConstructFP(void *(*mfp)(void *parent, tmsg_t msgType)) {
     rpcClose(this->transCli);
     rpcInit_.mfp = mfp;
     this->transCli = rpcOpen(&rpcInit_);
   }
-  void setPAndMFp(bool (*pfp)(void *parent, tmsg_t msgType), void *(*mfp)(void *parent, tmsg_t msgType)) {
+  void SetPAndMFp(bool (*pfp)(void *parent, tmsg_t msgType), void *(*mfp)(void *parent, tmsg_t msgType)) {
     rpcClose(this->transCli);
 
     rpcInit_.pfp = pfp;
@@ -88,6 +110,15 @@ class Client {
     SemWait();
     *resp = this->resp;
   }
+  void SendAndRecvNoHandle(SRpcMsg *req, SRpcMsg *resp) {
+    if (req->handle != NULL) {
+      rpcReleaseHandle(req->handle, TAOS_CONN_CLIENT);
+      req->handle = NULL;
+    }
+    SendAndRecv(req, resp);
+  }
+
+  void SendWithHandle(SRpcMsg *req, SRpcMsg *resp) {}
   void SemWait() { tsem_wait(&this->sem); }
   void SemPost() { tsem_post(&this->sem); }
   void Reset() {}
@@ -105,19 +136,20 @@ class Client {
 class Server {
  public:
   Server() {
-    memset(&rpcInit, 0, sizeof(rpcInit));
-    rpcInit.localPort = port;
-    rpcInit.label = (char *)label;
-    rpcInit.numOfThreads = 5;
-    rpcInit.cfp = processReq;
-    rpcInit.user = (char *)user;
-    rpcInit.secret = (char *)secret;
-    rpcInit.ckey = (char *)ckey;
-    rpcInit.spi = 1;
-    rpcInit.connType = TAOS_CONN_SERVER;
+    memset(&rpcInit_, 0, sizeof(rpcInit_));
+    rpcInit_.localPort = port;
+    rpcInit_.label = (char *)label;
+    rpcInit_.numOfThreads = 5;
+    rpcInit_.cfp = processReq;
+    rpcInit_.efp = NULL;
+    rpcInit_.user = (char *)user;
+    rpcInit_.secret = (char *)secret;
+    rpcInit_.ckey = (char *)ckey;
+    rpcInit_.spi = 1;
+    rpcInit_.connType = TAOS_CONN_SERVER;
   }
   void Start() {
-    this->transSrv = rpcOpen(&this->rpcInit);
+    this->transSrv = rpcOpen(&this->rpcInit_);
     taosMsleep(1000);
   }
   void Stop() {
@@ -125,6 +157,16 @@ class Server {
     rpcClose(this->transSrv);
     this->transSrv = NULL;
   }
+  void SetExceptFp(void (*efp)(void *parent, tmsg_t msgType)) {
+    this->Stop();
+    rpcInit_.efp = efp;
+    this->Start();
+  }
+  void SetSrvContinueSend(void (*cfp)(void *parent, SRpcMsg *pMsg, SEpSet *pEpSet)) {
+    this->Stop();
+    rpcInit_.cfp = cfp;
+    this->Start();
+  }
   void Restart() {
     this->Stop();
     this->Start();
@@ -135,7 +177,7 @@ class Server {
   }
 
  private:
-  SRpcInit rpcInit;
+  SRpcInit rpcInit_;
   void *   transSrv;
 };
 static void processReq(void *parent, SRpcMsg *pMsg, SEpSet *pEpSet) {
@@ -146,6 +188,20 @@ static void processReq(void *parent, SRpcMsg *pMsg, SEpSet *pEpSet) {
   rpcMsg.code = 0;
   rpcSendResponse(&rpcMsg);
 }
+
+static void processContinueSend(void *parent, SRpcMsg *pMsg, SEpSet *pEpSet) {
+  for (int i = 0; i < 9; i++) {
+    rpcRefHandle(pMsg->handle, TAOS_CONN_SERVER);
+  }
+  for (int i = 0; i < 10; i++) {
+    SRpcMsg rpcMsg = {0};
+    rpcMsg.pCont = rpcMallocCont(100);
+    rpcMsg.contLen = 100;
+    rpcMsg.handle = pMsg->handle;
+    rpcMsg.code = 0;
+    rpcSendResponse(&rpcMsg);
+  }
+}
 // client process;
 static void processResp(void *parent, SRpcMsg *pMsg, SEpSet *pEpSet) {
   Client *client = (Client *)parent;
@@ -170,7 +226,7 @@ static void initEnv() {
   tsAsyncLog = 0;
 
   std::string path = "/tmp/transport";
-  taosRemoveDir(path.c_str());
+  // taosRemoveDir(path.c_str());
   taosMkDir(path.c_str());
 
   tstrncpy(tsLogDir, path.c_str(), PATH_MAX);
@@ -178,6 +234,7 @@ static void initEnv() {
     printf("failed to init log file\n");
   }
 }
+
 class TransObj {
  public:
   TransObj() {
@@ -188,22 +245,39 @@ class TransObj {
     srv->Start();
   }
 
-  void RestartCli(CB cb) { cli->Restart(cb); }
-  void StopSrv() { srv->Stop(); }
+  void RestartCli(CB cb) {
+    //
+    cli->Restart(cb);
+  }
+  void StopSrv() {
+    //
+    srv->Stop();
+  }
   void SetCliPersistFp(bool (*pfp)(void *parent, tmsg_t msgType)) {
     // do nothing
-    cli->setPersistFP(pfp);
+    cli->SetPersistFP(pfp);
   }
   void SetCliMFp(void *(*mfp)(void *parent, tmsg_t msgType)) {
     // do nothing
-    cli->setConstructFP(mfp);
+    cli->SetConstructFP(mfp);
   }
-  void SetMAndPFp(bool (*pfp)(void *parent, tmsg_t msgType), void *(*mfp)(void *parent, tmsg_t msgType)) {
+  void SetCliMAndPFp(bool (*pfp)(void *parent, tmsg_t msgType), void *(*mfp)(void *parent, tmsg_t msgType)) {
     // do nothing
-    cli->setPAndMFp(pfp, mfp);
+    cli->SetPAndMFp(pfp, mfp);
+  }
+  // call when link broken, and notify query or fetch stop
+  void SetSrvExceptFp(void (*efp)(void *parent, tmsg_t msgType)) {
+    ////////
+    srv->SetExceptFp(efp);
+  }
+  void SetSrvContinueSend(void (*cfp)(void *parent, SRpcMsg *pMsg, SEpSet *pEpSet)) {
+    ///////
+    srv->SetSrvContinueSend(cfp);
   }
   void RestartSrv() { srv->Restart(); }
   void cliSendAndRecv(SRpcMsg *req, SRpcMsg *resp) { cli->SendAndRecv(req, resp); }
+  void cliSendAndRecvNoHandle(SRpcMsg *req, SRpcMsg *resp) { cli->SendAndRecvNoHandle(req, resp); }
+
   ~TransObj() {
     delete cli;
     delete srv;
@@ -256,20 +330,97 @@ TEST_F(TransEnv, 02StopServer) {
   tr->cliSendAndRecv(&req, &resp);
   assert(resp.code != 0);
 }
-TEST_F(TransEnv, clientUserDefined) {}
+TEST_F(TransEnv, clientUserDefined) {
+  tr->RestartSrv();
+  for (int i = 0; i < 10; i++) {
+    SRpcMsg req = {0}, resp = {0};
+    req.msgType = 0;
+    req.pCont = rpcMallocCont(10);
+    req.contLen = 10;
+    tr->cliSendAndRecv(&req, &resp);
+    assert(resp.code == 0);
+  }
+
+  //////////////////
+}
 
 TEST_F(TransEnv, cliPersistHandle) {
-  // impl late
-}
-TEST_F(TransEnv, srvPersistHandle) {
-  // impl later
+  tr->SetCliPersistFp(cliPersistHandle);
+  SRpcMsg resp = {0};
+  for (int i = 0; i < 10; i++) {
+    SRpcMsg req = {.handle = resp.handle};
+    req.msgType = 1;
+    req.pCont = rpcMallocCont(10);
+    req.contLen = 10;
+    tr->cliSendAndRecv(&req, &resp);
+    if (i == 5) {
+      std::cout << "stop server" << std::endl;
+      tr->StopSrv();
+    }
+    if (i >= 6) {
+      EXPECT_TRUE(resp.code != 0);
+    }
+  }
+  //////////////////
 }
 
-TEST_F(TransEnv, srvPersisHandleExcept) {
+TEST_F(TransEnv, cliReleaseHandle) {
+  tr->SetCliPersistFp(cliPersistHandle);
+
+  SRpcMsg resp = {0};
+  for (int i = 0; i < 10; i++) {
+    SRpcMsg req = {.handle = resp.handle};
+    req.msgType = 1;
+    req.pCont = rpcMallocCont(10);
+    req.contLen = 10;
+    tr->cliSendAndRecvNoHandle(&req, &resp);
+    // if (i == 5) {
+    //  std::cout << "stop server" << std::endl;
+    //  tr->StopSrv();
+    //}
+    // if (i >= 6) {
+    EXPECT_TRUE(resp.code == 0);
+    //}
+  }
+  //////////////////
+}
+TEST_F(TransEnv, cliReleaseHandleExcept) {
+  tr->SetCliPersistFp(cliPersistHandle);
+
+  SRpcMsg resp = {0};
+  for (int i = 0; i < 10; i++) {
+    SRpcMsg req = {.handle = resp.handle};
+    req.msgType = 1;
+    req.pCont = rpcMallocCont(10);
+    req.contLen = 10;
+    tr->cliSendAndRecvNoHandle(&req, &resp);
+    if (i == 5) {
+      std::cout << "stop server" << std::endl;
+      tr->StopSrv();
+    }
+    if (i >= 6) {
+      EXPECT_TRUE(resp.code != 0);
+    }
+  }
+  //////////////////
+}
+TEST_F(TransEnv, srvContinueSend) {
+  tr->SetSrvContinueSend(processContinueSend);
+  for (int i = 0; i < 10; i++) {
+    SRpcMsg req = {0}, resp = {0};
+    req.msgType = 1;
+    req.pCont = rpcMallocCont(10);
+    req.contLen = 10;
+    tr->cliSendAndRecv(&req, &resp);
+  }
+  taosMsleep(2000);
+}
+
+TEST_F(TransEnv, srvPersistHandleExcept) {
   // conn breken
   //
 }
-TEST_F(TransEnv, cliPersisHandleExcept) {
+TEST_F(TransEnv, cliPersistHandleExcept) {
   // conn breken
 }
 
@@ -282,3 +433,6 @@ TEST_F(TransEnv, multiSrvPersisHandleExcept) {
 TEST_F(TransEnv, queryExcept) {
   // query and conn is broken
 }
+TEST_F(TransEnv, noResp) {
+  // no resp
+}