diff --git a/source/libs/transport/src/transCli.c b/source/libs/transport/src/transCli.c
index 4ffaad3f84a5fab444aa0d72fe4c160019b68375..d64df9b0f3aea486560479f55a02274d3ff47162 100644
--- a/source/libs/transport/src/transCli.c
+++ b/source/libs/transport/src/transCli.c
@@ -95,8 +95,10 @@ static void clientHandleExcept(SCliConn* conn);
 // handle req from app
 static void clientHandleReq(SCliMsg* pMsg, SCliThrdObj* pThrd);
 
-static void clientMsgDestroy(SCliMsg* pMsg);
-static void destroyTransConnCtx(STransConnCtx* ctx);
+static void destroyUserdata(SRpcMsg* userdata);
+
+static void destroyCmsg(SCliMsg* cmsg);
+static void transDestroyConnCtx(STransConnCtx* ctx);
 // thread obj
 static SCliThrdObj* createThrdObj();
 static void         destroyThrdObj(SCliThrdObj* pThrd);
@@ -104,7 +106,8 @@ static void         destroyThrdObj(SCliThrdObj* pThrd);
 static void* clientThread(void* arg);
 
 static void clientHandleResp(SCliConn* conn) {
-  STransConnCtx* pCtx = ((SCliMsg*)conn->data)->ctx;
+  SCliMsg*       pMsg = conn->data;
+  STransConnCtx* pCtx = pMsg->ctx;
   SRpcInfo*      pRpc = pCtx->pTransInst;
 
   STransMsgHead* pHead = (STransMsgHead*)(conn->readBuf.buf);
@@ -122,41 +125,44 @@ static void clientHandleResp(SCliConn* conn) {
   (pRpc->cfp)(NULL, &rpcMsg, NULL);
   conn->notifyCount += 1;
 
-  SCliThrdObj* pThrd = conn->hostThrd;
-  tfree(conn->data);
-  // buf alread translated to rpcMsg.pCont
+  // buf's mem alread translated to rpcMsg.pCont
   transClearBuffer(&conn->readBuf);
 
   uv_read_start((uv_stream_t*)conn->stream, clientAllocBufferCb, clientReadCb);
+
+  SCliThrdObj* pThrd = conn->hostThrd;
   addConnToPool(pThrd->pool, pCtx->ip, pCtx->port, conn);
 
+  destroyCmsg(pMsg);
+  conn->data = NULL;
   // start thread's timer of conn pool if not active
   if (!uv_is_active((uv_handle_t*)pThrd->pTimer) && pRpc->idleTime > 0) {
     uv_timer_start((uv_timer_t*)pThrd->pTimer, clientTimeoutCb, CONN_PERSIST_TIME(pRpc->idleTime) / 2, 0);
   }
-  destroyTransConnCtx(pCtx);
 }
 static void clientHandleExcept(SCliConn* pConn) {
   if (pConn->data == NULL) {
+    // handle conn except in conn pool
     clientConnDestroy(pConn, true);
     return;
   }
-  tDebug("conn %p destroy", pConn);
+  tDebug("conn %p start to destroy", pConn);
   SCliMsg* pMsg = pConn->data;
-  transFreeMsg((pMsg->msg.pCont));
-  pMsg->msg.pCont = NULL;
+
+  destroyUserdata(&pMsg->msg);
 
   STransConnCtx* pCtx = pMsg->ctx;
-  SRpcInfo*      pRpc = pCtx->pTransInst;
 
   SRpcMsg rpcMsg = {0};
   rpcMsg.ahandle = pCtx->ahandle;
   rpcMsg.code = -1;
   // SRpcInfo* pRpc = pMsg->ctx->pRpc;
-  (pRpc->cfp)(NULL, &rpcMsg, NULL);
-  tfree(pConn->data);
+  (pCtx->pTransInst->cfp)(NULL, &rpcMsg, NULL);
   pConn->notifyCount += 1;
-  destroyTransConnCtx(pCtx);
+
+  destroyCmsg(pMsg);
+  pConn->data = NULL;
+  // transDestroyConnCtx(pCtx);
   clientConnDestroy(pConn, true);
 }
 
@@ -236,6 +242,7 @@ static void addConnToPool(void* pool, char* ip, uint32_t port, SCliConn* conn) {
   tDebug("conn %p added to conn pool, read buf cap: %d", conn, conn->readBuf.cap);
 
   SRpcInfo* pRpc = ((SCliThrdObj*)conn->hostThrd)->pTransInst;
+
   conn->expireTime = taosGetTimestampMs() + CONN_PERSIST_TIME(pRpc->idleTime);
   SConnList* plist = taosHashGet((SHashObj*)pool, key, strlen(key));
   conn->notifyCount = 0;
@@ -282,6 +289,9 @@ static void clientReadCb(uv_stream_t* handle, ssize_t nread, const uv_buf_t* buf
   }
   assert(nread <= 0);
   if (nread == 0) {
+    // ref http://docs.libuv.org/en/v1.x/stream.html?highlight=uv_read_start#c.uv_read_cb
+    // nread might be 0, which does not indicate an error or EOF. This is equivalent to EAGAIN or EWOULDBLOCK under
+    // read(2).
     return;
   }
   if (nread < 0 || nread == UV_EOF) {
@@ -321,11 +331,12 @@ static void clientWriteCb(uv_write_t* req, int status) {
   if (status == 0) {
     tDebug("conn %p data already was written out", pConn);
     SCliMsg* pMsg = pConn->data;
-    if (pMsg != NULL) {
-      transFreeMsg((pMsg->msg.pCont));
-      pMsg->msg.pCont = NULL;
+    if (pMsg == NULL) {
+      destroy
+          // handle
+          return;
     }
-
+    destroyUserdata(&pMsg->msg);
   } else {
     tError("conn %p failed to write: %s", pConn, uv_err_name(status));
     clientHandleExcept(pConn);
@@ -453,8 +464,20 @@ void* taosInitClient(uint32_t ip, uint32_t port, char* label, int numOfThreads,
   }
   return cli;
 }
-static void clientMsgDestroy(SCliMsg* pMsg) {
-  // impl later
+
+static void destroyUserdata(SRpcMsg* userdata) {
+  if (userdata->pCont == NULL) {
+    return;
+  }
+  transFreeMsg(userdata->pCont);
+  userdata->pCont = NULL;
+}
+static void destroyCmsg(SCliMsg* pMsg) {
+  if (pMsg == NULL) {
+    return;
+  }
+  transDestroyConnCtx(pMsg->ctx);
+  destroyUserdata(&pMsg->msg);
   free(pMsg);
 }
 static SCliThrdObj* createThrdObj() {
@@ -487,7 +510,7 @@ static void destroyThrdObj(SCliThrdObj* pThrd) {
   free(pThrd);
 }
 
-static void destroyTransConnCtx(STransConnCtx* ctx) {
+static void transDestroyConnCtx(STransConnCtx* ctx) {
   if (ctx != NULL) {
     free(ctx->ip);
   }
diff --git a/source/libs/transport/src/transSrv.c b/source/libs/transport/src/transSrv.c
index 485ed904e83f2000a9b9a0d552a0022e3babb004..f36d9bd4937221f2d84e97103f3a8f42eef90b52 100644
--- a/source/libs/transport/src/transSrv.c
+++ b/source/libs/transport/src/transSrv.c
@@ -91,7 +91,7 @@ static void uvWorkerAsyncCb(uv_async_t* handle);
 
 static void uvPrepareSendData(SSrvMsg* msg, uv_buf_t* wb);
 static void uvStartSendResp(SSrvMsg* msg);
-static void destroySrvMsg(SSrvConn* conn);
+static void destroySmsg(SSrvMsg* smsg);
 // check whether already read complete packet
 static bool      readComplete(SConnBuffer* buf);
 static SSrvConn* createConn();
@@ -305,8 +305,10 @@ void uvOnTimeoutCb(uv_timer_t* handle) {
 
 void uvOnWriteCb(uv_write_t* req, int status) {
   SSrvConn* conn = req->data;
-  SSrvMsg*  smsg = conn->pSrvMsg;
-  destroySrvMsg(conn);
+
+  SSrvMsg* smsg = conn->pSrvMsg;
+  destroySmsg(smsg);
+  conn->pSrvMsg = NULL;
 
   transClearBuffer(&conn->readBuf);
   if (status == 0) {
@@ -362,14 +364,12 @@ static void uvStartSendResp(SSrvMsg* smsg) {
 
   return;
 }
-static void destroySrvMsg(SSrvConn* conn) {
-  SSrvMsg* smsg = conn->pSrvMsg;
+static void destroySmsg(SSrvMsg* smsg) {
   if (smsg == NULL) {
     return;
   }
   transFreeMsg(smsg->msg.pCont);
-  free(conn->pSrvMsg);
-  conn->pSrvMsg = NULL;
+  free(smsg);
 }
 void uvWorkerAsyncCb(uv_async_t* handle) {
   SWorkThrdObj* pThrd = handle->data;
@@ -555,7 +555,8 @@ static void destroyConn(SSrvConn* conn, bool clear) {
     return;
   }
   transDestroyBuffer(&conn->readBuf);
-  destroySrvMsg(conn);
+  destroySmsg(conn->pSrvMsg);
+  conn->pSrvMsg = NULL;
 
   if (clear) {
     uv_close((uv_handle_t*)conn->pTcp, uvDestroyConn);
diff --git a/source/libs/transport/test/rserver.c b/source/libs/transport/test/rserver.c
index 12d8a01819658174e676399e26331d053b79440c..d1a587f4e5539a45001cafa28e58f134f9bcdad3 100644
--- a/source/libs/transport/test/rserver.c
+++ b/source/libs/transport/test/rserver.c
@@ -165,6 +165,7 @@ int main(int argc, char *argv[]) {
     tError("failed to start RPC server");
     return -1;
   }
+  // sleep(5);
 
   tInfo("RPC server is running, ctrl-c to exit");
 
@@ -172,7 +173,6 @@ int main(int argc, char *argv[]) {
     dataFd = open(dataName, O_APPEND | O_CREAT | O_WRONLY, S_IRWXU | S_IRWXG | S_IRWXO);
     if (dataFd < 0) tInfo("failed to open data file, reason:%s", strerror(errno));
   }
-
   qhandle = taosOpenQueue();
   qset = taosOpenQset();
   taosAddIntoQset(qset, qhandle, NULL);