diff --git a/include/libs/transport/trpc.h b/include/libs/transport/trpc.h
index 6bc28e3ea03719e16f75a0aab98fa9b9228eed1f..af5afb51c5c065dbe5c644bda1bcabba65c36af2 100644
--- a/include/libs/transport/trpc.h
+++ b/include/libs/transport/trpc.h
@@ -38,13 +38,13 @@ typedef struct SRpcConnInfo {
 
 typedef struct SRpcMsg {
   tmsg_t  msgType;
-  tmsg_t  expectMsgType;
   void *  pCont;
   int     contLen;
   int32_t code;
-  void *  handle;   // rpc handle returned to app
-  void *  ahandle;  // app handle set by client
-  int     noResp;   // has response or not(default 0 indicate resp);
+  void *  handle;         // rpc handle returned to app
+  void *  ahandle;        // app handle set by client
+  int     noResp;         // has response or not(default 0, 0: resp, 1: no resp);
+  int     persistHandle;  // persist handle or not
 
 } SRpcMsg;
 
@@ -69,18 +69,19 @@ 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);
-
-  // 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
-  bool (*efp)(void *parent, tmsg_t msgType);
-
   void *parent;
 } SRpcInit;
 
+typedef struct {
+  void *  val;
+  int32_t len;
+  void (*free)(void *arg);
+} SRpcCtxVal;
+
+typedef struct {
+  SHashObj *args;
+} SRpcCtx;
+
 int32_t rpcInit();
 void    rpcCleanup();
 void *  rpcOpen(const SRpcInit *pRpc);
@@ -89,16 +90,17 @@ void *  rpcMallocCont(int contLen);
 void    rpcFreeCont(void *pCont);
 void *  rpcReallocCont(void *ptr, int contLen);
 void    rpcSendRequest(void *thandle, const SEpSet *pEpSet, SRpcMsg *pMsg, int64_t *rid);
-void    rpcSendResponse(const SRpcMsg *pMsg);
-void    rpcSendRedirectRsp(void *pConn, const SEpSet *pEpSet);
-int     rpcGetConnInfo(void *thandle, SRpcConnInfo *pInfo);
-void    rpcSendRecv(void *shandle, SEpSet *pEpSet, SRpcMsg *pReq, SRpcMsg *pRsp);
-int     rpcReportProgress(void *pConn, char *pCont, int contLen);
-void    rpcCancelRequest(int64_t rid);
-
+void    rpcSendRequestWithCtx(void *thandle, const SEpSet *pEpSet, SRpcMsg *pMsg, int64_t *rid, SRpcCtx *ctx);
+
+void rpcSendResponse(const SRpcMsg *pMsg);
+void rpcSendRedirectRsp(void *pConn, const SEpSet *pEpSet);
+int  rpcGetConnInfo(void *thandle, SRpcConnInfo *pInfo);
+void rpcSendRecv(void *shandle, SEpSet *pEpSet, SRpcMsg *pReq, SRpcMsg *pRsp);
+int  rpcReportProgress(void *pConn, char *pCont, int contLen);
+void rpcCancelRequest(int64_t rid);
+void rpcRegisterBrokenLinkArg(SRpcMsg *msg);
 // just release client conn to rpc instance, no close sock
-void rpcReleaseHandle(void *handle, int8_t type);
-
+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/client/src/clientEnv.c b/source/client/src/clientEnv.c
index 2233742625e6e733f184bd2c4e7eac376afd9139..24abbd263c7750787c99a3472002c1b993842bd0 100644
--- a/source/client/src/clientEnv.c
+++ b/source/client/src/clientEnv.c
@@ -90,7 +90,6 @@ void *openTransporter(const char *user, const char *auth, int32_t numOfThread) {
   rpcInit.label = "TSC";
   rpcInit.numOfThreads = numOfThread;
   rpcInit.cfp = processMsgFromServer;
-  rpcInit.pfp = persistConnForSpecificMsg;
   rpcInit.sessions = tsMaxConnections;
   rpcInit.connType = TAOS_CONN_CLIENT;
   rpcInit.user = (char *)user;
diff --git a/source/libs/qcom/src/queryUtil.c b/source/libs/qcom/src/queryUtil.c
index 63fbf59c064a91a883a0ae52ad7fb9e1c56b1c55..b39d3e6e374815efc30ee439928f9f574f97f7f5 100644
--- a/source/libs/qcom/src/queryUtil.c
+++ b/source/libs/qcom/src/queryUtil.c
@@ -155,6 +155,10 @@ int32_t asyncSendMsgToServer(void* pTransporter, SEpSet* epSet, int64_t* pTransp
                     .ahandle = (void*)pInfo,
                     .handle = pInfo->msgInfo.handle,
                     .code = 0};
+  if (pInfo->msgType == TDMT_VND_QUERY || pInfo->msgType == TDMT_VND_FETCH ||
+      pInfo->msgType == TDMT_VND_QUERY_CONTINUE) {
+    rpcMsg.persistHandle = 1;
+  }
 
   assert(pInfo->fp != NULL);
 
diff --git a/source/libs/transport/inc/transComm.h b/source/libs/transport/inc/transComm.h
index 8ea65b193d2911878bd9e74af8c814232c954a27..c861ed350e229fdd0d2a159a1e018c5fc17273ee 100644
--- a/source/libs/transport/inc/transComm.h
+++ b/source/libs/transport/inc/transComm.h
@@ -14,6 +14,10 @@
  */
 #ifdef USE_UV
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include <uv.h>
 #include "lz4.h"
 #include "os.h"
@@ -121,24 +125,21 @@ typedef struct {
 } SRpcReqContext;
 
 typedef SRpcMsg      STransMsg;
+typedef SRpcCtx      STransCtx;
+typedef SRpcCtxVal   STransCtxVal;
 typedef SRpcInfo     STrans;
 typedef SRpcConnInfo STransHandleInfo;
 
 typedef struct {
-  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
-  // int32_t  code;     // error code
-  // 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
+  SEpSet  epSet;     // ip list provided by app
+  void*   ahandle;   // handle provided by app
+  tmsg_t  msgType;   // message type
   int8_t  connType;  // connection type cli/srv
   int64_t rid;       // refId returned by taosAddRef
 
-  STransMsg* pRsp;  // for synchronous API
-  tsem_t*    pSem;  // for synchronous API
+  STransCtx  appCtx;  //
+  STransMsg* pRsp;    // for synchronous API
+  tsem_t*    pSem;    // for synchronous API
 
   int      hThrdIdx;
   char*    ip;
@@ -150,11 +151,12 @@ typedef struct {
 
 typedef struct {
   char version : 4;  // RPC version
-  char comp : 4;     // compression algorithm, 0:no compression 1:lz4
-  char resflag : 2;  // reserved bits
-  char spi : 1;      // security parameter index
+  char comp : 2;     // compression algorithm, 0:no compression 1:lz4
+  char noResp : 2;   // noResp bits, 0: resp, 1: resp
+  char persist : 2;  // persist handle,0: no persit, 1: persist handle
+  char release : 2;
   char secured : 2;
-  char encrypt : 3;  // encrypt algorithm, 0: no encryption
+  char spi : 2;
 
   uint32_t code;  // del later
   uint32_t msgType;
@@ -179,6 +181,9 @@ typedef struct {
 
 #pragma pack(pop)
 
+typedef enum { Normal, Quit, Release, Register } STransMsgType;
+typedef enum { ConnNormal, ConnAcquire, ConnRelease, ConnBroken } ConnStatus;
+
 #define container_of(ptr, type, member) ((type*)((char*)(ptr)-offsetof(type, member)))
 #define RPC_RESERVE_SIZE (sizeof(STranConnCtx))
 
@@ -255,9 +260,10 @@ 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 transSendRequest(void* shandle, const char* ip, uint32_t port, STransMsg* pMsg, STransCtx* pCtx);
 void transSendRecv(void* shandle, const char* ip, uint32_t port, STransMsg* pMsg, STransMsg* pRsp);
-void transSendResponse(const STransMsg* pMsg);
+void transSendResponse(const STransMsg* msg);
+void transRegisterMsg(const STransMsg* msg);
 int  transGetConnInfo(void* thandle, STransHandleInfo* pInfo);
 
 void* transInitServer(uint32_t ip, uint32_t port, char* label, int numOfThreads, void* fp, void* shandle);
@@ -266,4 +272,14 @@ void* transInitClient(uint32_t ip, uint32_t port, char* label, int numOfThreads,
 void transCloseClient(void* arg);
 void transCloseServer(void* arg);
 
+void  transCtxInit(STransCtx* ctx);
+void  transCtxDestroy(STransCtx* ctx);
+void  transCtxClear(STransCtx* ctx);
+void  transCtxMerge(STransCtx* dst, STransCtx* src);
+void* transCtxDumpVal(STransCtx* ctx, int32_t key);
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif
diff --git a/source/libs/transport/inc/transportInt.h b/source/libs/transport/inc/transportInt.h
index e7393804674341417e6589d5b6f99961d39e856d..139540896092be9b7b3c28f1ba9781b4bd63deca 100644
--- a/source/libs/transport/inc/transportInt.h
+++ b/source/libs/transport/inc/transportInt.h
@@ -63,9 +63,6 @@ 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);
-  void* (*mfp)(void* parent, tmsg_t msgType);
-  bool (*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 2cab03f133620fce7d2129f251320946bcc010ea..317f80c48d00b0da50505a059e56b3ea05ff309a 100644
--- a/source/libs/transport/src/trans.c
+++ b/source/libs/transport/src/trans.c
@@ -39,9 +39,6 @@ void* rpcOpen(const SRpcInit* pInit) {
   // register callback handle
   pRpc->cfp = pInit->cfp;
   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;
@@ -121,7 +118,12 @@ void rpcCancelRequest(int64_t rid) { return; }
 void rpcSendRequest(void* shandle, const SEpSet* pEpSet, SRpcMsg* pMsg, int64_t* pRid) {
   char*    ip = (char*)(pEpSet->eps[pEpSet->inUse].fqdn);
   uint32_t port = pEpSet->eps[pEpSet->inUse].port;
-  transSendRequest(shandle, ip, port, pMsg);
+  transSendRequest(shandle, ip, port, pMsg, NULL);
+}
+void rpcSendRequestWithCtx(void* shandle, const SEpSet* pEpSet, SRpcMsg* pMsg, int64_t* pRid, SRpcCtx* pCtx) {
+  char*    ip = (char*)(pEpSet->eps[pEpSet->inUse].fqdn);
+  uint32_t port = pEpSet->eps[pEpSet->inUse].port;
+  transSendRequest(shandle, ip, port, pMsg, pCtx);
 }
 void rpcSendRecv(void* shandle, SEpSet* pEpSet, SRpcMsg* pMsg, SRpcMsg* pRsp) {
   char*    ip = (char*)(pEpSet->eps[pEpSet->inUse].fqdn);
@@ -142,6 +144,7 @@ void rpcUnrefHandle(void* handle, int8_t type) {
   (*taosUnRefHandle[type])(handle);
 }
 
+void rpcRegisterBrokenLinkArg(SRpcMsg* msg) { rpcSendResponse(msg); }
 void rpcReleaseHandle(void* handle, int8_t type) {
   assert(type == TAOS_CONN_SERVER || type == TAOS_CONN_CLIENT);
   (*transReleaseHandle[type])(handle);
diff --git a/source/libs/transport/src/transCli.c b/source/libs/transport/src/transCli.c
index df35b8d67b2e2b0c91c154c4ff3d7cb951d0d8b1..842b5a1b4b7839ce3edcf63e8cb2cd9fc9fc445a 100644
--- a/source/libs/transport/src/transCli.c
+++ b/source/libs/transport/src/transCli.c
@@ -17,11 +17,6 @@
 
 #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;
@@ -35,8 +30,10 @@ typedef struct SCliConn {
   uint64_t     expireTime;
   int          hThrdIdx;
   bool         broken;  // link broken or not
+  STransCtx    ctx;
 
-  int persist;  //
+  ConnStatus status;   //
+  int        release;  // 1: release
   // spi configure
   char spi;
   char secured;
@@ -55,7 +52,7 @@ typedef struct SCliMsg {
   STransMsg      msg;
   queue          q;
   uint64_t       st;
-  SCliMsgType    type;
+  STransMsgType  type;
 } SCliMsg;
 
 typedef struct SCliThrdObj {
@@ -113,10 +110,12 @@ static void      cliSend(SCliConn* pConn);
 static void cliHandleResp(SCliConn* conn);
 // handle except about conn
 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 (*cliAsyncHandle[])(SCliMsg* pMsg, SCliThrdObj* pThrd) = {cliHandleReq, cliHandleQuit, cliHandleRelease};
 
 static void cliSendQuit(SCliThrdObj* thrd);
 static void destroyUserdata(STransMsg* userdata);
@@ -133,6 +132,20 @@ static void         destroyThrdObj(SCliThrdObj* pThrd);
 #define CONN_PERSIST_TIME(para) (para * 1000 * 10)
 #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_SHOULD_RELEASE(conn, head)                            \
+  do {                                                             \
+    if ((head)->release == 1 && (head->msgLen) == sizeof(*head)) { \
+      conn->status = ConnRelease;                                  \
+      transClearBuffer(&conn->readBuf);                            \
+      transFreeMsg(transContFromHead((char*)head));                \
+      if (T_REF_VAL_GET(conn) == 1) {                              \
+        SCliThrdObj* thrd = conn->hostThrd;                        \
+        addConnToPool(thrd->pool, conn);                           \
+      }                                                            \
+      goto _RETURN;                                                \
+    }                                                              \
+  } while (0)
+
 #define CONN_HANDLE_THREAD_QUIT(conn, thrd) \
   do {                                      \
     if (thrd->quit) {                       \
@@ -151,14 +164,16 @@ static void         destroyThrdObj(SCliThrdObj* pThrd);
 
 #define CONN_SET_PERSIST_BY_APP(conn) \
   do {                                \
-    if (conn->persist == false) {     \
-      conn->persist = true;           \
+    if (conn->status == ConnNormal) { \
+      conn->status = ConnAcquire;     \
       transRefCliHandle(conn);        \
     }                                 \
   } while (0)
-#define CONN_NO_PERSIST_BY_APP(conn) ((conn)->persist == false)
+#define CONN_NO_PERSIST_BY_APP(conn) ((conn)->status == ConnNormal && T_REF_VAL_GET(conn) == 1)
 
 #define REQUEST_NO_RESP(msg) ((msg)->noResp == 1)
+#define REQUEST_PERSIS_HANDLE(msg) ((msg)->persistHandle == 1)
+#define REQUEST_RELEASE_HANDLE(cmsg) ((cmsg)->type == Release)
 
 static void* cliWorkThread(void* arg);
 
@@ -177,7 +192,6 @@ void cliHandleResp(SCliConn* conn) {
   STransMsgHead* pHead = (STransMsgHead*)(conn->readBuf.buf);
   pHead->code = htonl(pHead->code);
   pHead->msgLen = htonl(pHead->msgLen);
-
   STransMsg transMsg = {0};
   transMsg.contLen = transContLenFromMsg(pHead->msgLen);
   transMsg.pCont = transContFromHead((char*)pHead);
@@ -185,6 +199,8 @@ void cliHandleResp(SCliConn* conn) {
   transMsg.msgType = pHead->msgType;
   transMsg.ahandle = NULL;
 
+  CONN_SHOULD_RELEASE(conn, pHead);
+
   SCliMsg* pMsg = NULL;
   if (taosArrayGetSize(conn->cliMsgs) > 0) {
     pMsg = taosArrayGetP(conn->cliMsgs, 0);
@@ -193,16 +209,15 @@ void cliHandleResp(SCliConn* conn) {
 
   STransConnCtx* pCtx = pMsg ? pMsg->ctx : NULL;
   if (pMsg == NULL && !CONN_NO_PERSIST_BY_APP(conn)) {
-    transMsg.ahandle = pTransInst->mfp ? (*pTransInst->mfp)(pTransInst->parent, transMsg.msgType) : NULL;
+    transMsg.ahandle = transCtxDumpVal(&conn->ctx, transMsg.msgType);
   } else {
     transMsg.ahandle = pCtx ? pCtx->ahandle : NULL;
   }
   // buf's mem alread translated to transMsg.pCont
   transClearBuffer(&conn->readBuf);
 
-  if (pTransInst->pfp != NULL && (*pTransInst->pfp)(pTransInst->parent, transMsg.msgType)) {
+  if (!CONN_NO_PERSIST_BY_APP(conn)) {
     transMsg.handle = conn;
-    CONN_SET_PERSIST_BY_APP(conn);
     tDebug("%s cli conn %p ref by app", CONN_GET_INST_LABEL(conn), conn);
   }
 
@@ -241,6 +256,8 @@ void cliHandleResp(SCliConn* conn) {
   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);
   }
+_RETURN:
+  return;
 }
 
 void cliHandleExcept(SCliConn* pConn) {
@@ -268,7 +285,7 @@ void cliHandleExcept(SCliConn* pConn) {
     transMsg.ahandle = NULL;
 
     if (pMsg == NULL && !CONN_NO_PERSIST_BY_APP(pConn)) {
-      transMsg.ahandle = pTransInst->mfp ? (*pTransInst->mfp)(pTransInst->parent, transMsg.msgType) : NULL;
+      transMsg.ahandle = transCtxDumpVal(&pConn->ctx, transMsg.msgType);
     } else {
       transMsg.ahandle = pCtx ? pCtx->ahandle : NULL;
     }
@@ -359,6 +376,7 @@ static SCliConn* getConnFromPool(void* pool, char* ip, uint32_t port) {
 static void addConnToPool(void* pool, SCliConn* conn) {
   char key[128] = {0};
 
+  transCtxDestroy(&conn->ctx);
   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);
@@ -367,6 +385,7 @@ static void addConnToPool(void* pool, SCliConn* conn) {
 
   conn->expireTime = taosGetTimestampMs() + CONN_PERSIST_TIME(pTransInst->idleTime);
   SConnList* plist = taosHashGet((SHashObj*)pool, key, strlen(key));
+  conn->status = ConnNormal;
   // list already create before
   assert(plist != NULL);
   QUEUE_PUSH(&plist->conn, &conn->conn);
@@ -420,16 +439,16 @@ static SCliConn* cliCreateConn(SCliThrdObj* pThrd) {
   conn->writeReq.data = conn;
   conn->connReq.data = conn;
   conn->cliMsgs = taosArrayInit(2, sizeof(void*));
-
   QUEUE_INIT(&conn->conn);
   conn->hostThrd = pThrd;
-  conn->persist = false;
-  conn->broken = false;
+  conn->status = ConnNormal;
+  conn->broken = 0;
   transRefCliHandle(conn);
   return conn;
 }
 static void cliDestroyConn(SCliConn* conn, bool clear) {
   tTrace("%s cli conn %p remove from conn pool", CONN_GET_INST_LABEL(conn), conn);
+
   QUEUE_REMOVE(&conn->conn);
   if (clear) {
     uv_close((uv_handle_t*)conn->stream, cliDestroy);
@@ -439,6 +458,7 @@ static void cliDestroy(uv_handle_t* handle) {
   SCliConn* conn = handle->data;
   free(conn->ip);
   free(conn->stream);
+  transCtxDestroy(&conn->ctx);
   taosArrayDestroy(conn->cliMsgs);
   tTrace("%s cli conn %p destroy successfully", CONN_GET_INST_LABEL(conn), conn);
   free(conn);
@@ -490,7 +510,10 @@ void cliSend(SCliConn* pConn) {
   STrans*      pTransInst = pThrd->pTransInst;
 
   STransMsg* pMsg = (STransMsg*)(&pCliMsg->msg);
-
+  if (pMsg->pCont == 0) {
+    pMsg->pCont = (void*)rpcMallocCont(0);
+    pMsg->contLen = 0;
+  }
   STransMsgHead* pHead = transHeadFromCont(pMsg->pCont);
   int            msgLen = transMsgLenFromCont(pMsg->contLen);
 
@@ -513,15 +536,22 @@ void cliSend(SCliConn* pConn) {
     msgLen += sizeof(STransUserMsg);
   }
 
-  pHead->resflag = REQUEST_NO_RESP(pMsg) ? 1 : 0;
+  pHead->noResp = REQUEST_NO_RESP(pMsg) ? 1 : 0;
+
+  pHead->persist = REQUEST_PERSIS_HANDLE(pMsg) ? 1 : 0;
   pHead->msgType = pMsg->msgType;
   pHead->msgLen = (int32_t)htonl((uint32_t)msgLen);
+  pHead->release = REQUEST_RELEASE_HANDLE(pCliMsg) ? 1 : 0;
 
   uv_buf_t wb = uv_buf_init((char*)pHead, msgLen);
   tDebug("%s cli conn %p %s is send to %s:%d, local info %s:%d", CONN_GET_INST_LABEL(pConn), pConn,
          TMSG_INFO(pHead->msgType), taosInetNtoa(pConn->addr.sin_addr), ntohs(pConn->addr.sin_port),
          taosInetNtoa(pConn->locaddr.sin_addr), ntohs(pConn->locaddr.sin_port));
 
+  if (pHead->persist == 1) {
+    CONN_SET_PERSIST_BY_APP(pConn);
+  }
+
   pConn->writeReq.data = pConn;
   uv_write(&pConn->writeReq, (uv_stream_t*)pConn->stream, &wb, 1, cliSendCb);
 
@@ -562,22 +592,13 @@ static void cliHandleQuit(SCliMsg* pMsg, SCliThrdObj* pThrd) {
 }
 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);
+  tDebug("%s cli conn %p start to release to inst", CONN_GET_INST_LABEL(conn), conn);
 
-  while (taosArrayGetSize(conn->cliMsgs) > 0) {
-    SCliMsg* pMsg = taosArrayGetP(conn->cliMsgs, 0);
-    destroyCmsg(pMsg);
-    taosArrayRemove(conn->cliMsgs, 0);
-  }
-
-  transDestroyBuffer(&conn->readBuf);
-  if (conn->persist && T_REF_VAL_GET(conn) >= 2) {
-    conn->persist = false;
-    transUnrefCliHandle(conn);
-    addConnToPool(pThrd->pool, conn);
-  } else {
-    transUnrefCliHandle(conn);
+  taosArrayPush(conn->cliMsgs, &pMsg);
+  if (taosArrayGetSize(conn->cliMsgs) >= 2) {
+    return;  // send one by one
   }
+  cliSend(conn);
 }
 
 SCliConn* cliGetConn(SCliMsg* pMsg, SCliThrdObj* pThrd) {
@@ -609,10 +630,12 @@ void cliHandleReq(SCliMsg* pMsg, SCliThrdObj* pThrd) {
   if (conn != NULL) {
     conn->hThrdIdx = pCtx->hThrdIdx;
 
+    transCtxMerge(&conn->ctx, &pCtx->appCtx);
     if (taosArrayGetSize(conn->cliMsgs) > 0) {
       taosArrayPush(conn->cliMsgs, &pMsg);
       return;
     }
+
     taosArrayPush(conn->cliMsgs, &pMsg);
     transDestroyBuffer(&conn->readBuf);
     cliSend(conn);
@@ -652,14 +675,10 @@ static void cliAsyncCb(uv_async_t* handle) {
     QUEUE_REMOVE(h);
 
     SCliMsg* pMsg = QUEUE_DATA(h, SCliMsg, q);
-
-    if (pMsg->type == Normal) {
-      cliHandleReq(pMsg, pThrd);
-    } else if (pMsg->type == Quit) {
-      cliHandleQuit(pMsg, pThrd);
-    } else if (pMsg->type == Release) {
-      cliHandleRelease(pMsg, pThrd);
+    if (pMsg == NULL) {
+      continue;
     }
+    (*cliAsyncHandle[pMsg->type])(pMsg, pThrd);
     count++;
   }
   if (count >= 2) {
@@ -802,13 +821,13 @@ void transReleaseCliHandle(void* handle) {
 
   STransMsg tmsg = {.handle = handle};
   SCliMsg*  cmsg = calloc(1, sizeof(SCliMsg));
-  cmsg->type = Release;
   cmsg->msg = tmsg;
+  cmsg->type = Release;
 
   transSendAsync(thrd->asyncPool, &cmsg->q);
 }
 
-void transSendRequest(void* shandle, const char* ip, uint32_t port, STransMsg* pMsg) {
+void transSendRequest(void* shandle, const char* ip, uint32_t port, STransMsg* pMsg, STransCtx* ctx) {
   STrans* pTransInst = (STrans*)shandle;
   int     index = CONN_HOST_THREAD_INDEX((SCliConn*)pMsg->handle);
   if (index == -1) {
@@ -818,7 +837,7 @@ void transSendRequest(void* shandle, const char* ip, uint32_t port, STransMsg* p
   if (transCompressMsg(pMsg->pCont, pMsg->contLen, &flen)) {
     // imp later
   }
-  tDebug("send request at thread:%d %p", index, pMsg);
+  tDebug("send request at thread:%d %p, dst: %s:%d", index, pMsg, ip, port);
   STransConnCtx* pCtx = calloc(1, sizeof(STransConnCtx));
   pCtx->ahandle = pMsg->ahandle;
   pCtx->msgType = pMsg->msgType;
@@ -826,6 +845,10 @@ void transSendRequest(void* shandle, const char* ip, uint32_t port, STransMsg* p
   pCtx->port = port;
   pCtx->hThrdIdx = index;
 
+  if (ctx != NULL) {
+    pCtx->appCtx = *ctx;
+  }
+
   assert(pTransInst->connType == TAOS_CONN_CLIENT);
   // atomic or not
 
@@ -833,10 +856,12 @@ void transSendRequest(void* shandle, const char* ip, uint32_t port, STransMsg* p
   cliMsg->ctx = pCtx;
   cliMsg->msg = *pMsg;
   cliMsg->st = taosGetTimestampUs();
+  cliMsg->type = Normal;
 
   SCliThrdObj* thrd = ((SCliObj*)pTransInst->tcphandle)->pThreadObj[index];
   transSendAsync(thrd->asyncPool, &(cliMsg->q));
 }
+
 void transSendRecv(void* shandle, const char* ip, uint32_t port, STransMsg* pReq, STransMsg* pRsp) {
   STrans* pTransInst = (STrans*)shandle;
   int     index = CONN_HOST_THREAD_INDEX(pReq->handle);
@@ -858,6 +883,7 @@ void transSendRecv(void* shandle, const char* ip, uint32_t port, STransMsg* pReq
   cliMsg->ctx = pCtx;
   cliMsg->msg = *pReq;
   cliMsg->st = taosGetTimestampUs();
+  cliMsg->type = Normal;
 
   SCliThrdObj* thrd = ((SCliObj*)pTransInst->tcphandle)->pThreadObj[index];
   transSendAsync(thrd->asyncPool, &(cliMsg->q));
diff --git a/source/libs/transport/src/transComm.c b/source/libs/transport/src/transComm.c
index 7123593a33bc5e64f28f9763ec4429e1531167fc..2c90efc3aa5d236a3bb65d1063f595bc3e9b72ff 100644
--- a/source/libs/transport/src/transComm.c
+++ b/source/libs/transport/src/transComm.c
@@ -155,9 +155,9 @@ bool transReadComplete(SConnBuffer* connBuf) {
   }
   return false;
 }
-int transPackMsg(STransMsgHead* msgHead, bool sercured, bool auth) {return 0;}
+int transPackMsg(STransMsgHead* msgHead, bool sercured, bool auth) { return 0; }
 
-int transUnpackMsg(STransMsgHead* msgHead) {return 0;}
+int transUnpackMsg(STransMsgHead* msgHead) { return 0; }
 int transDestroyBuffer(SConnBuffer* buf) {
   if (buf->cap > 0) {
     tfree(buf->buf);
@@ -224,4 +224,56 @@ int transSendAsync(SAsyncPool* pool, queue* q) {
   return uv_async_send(async);
 }
 
+void transCtxInit(STransCtx* ctx) {
+  // init transCtx
+  ctx->args = taosHashInit(2, taosGetDefaultHashFunction(TSDB_DATA_TYPE_UINT), true, HASH_NO_LOCK);
+}
+void transCtxDestroy(STransCtx* ctx) {
+  if (ctx->args == NULL) {
+    return;
+  }
+
+  STransCtxVal* iter = taosHashIterate(ctx->args, NULL);
+  while (iter) {
+    iter->free(iter->val);
+    iter = taosHashIterate(ctx->args, iter);
+  }
+  taosHashCleanup(ctx->args);
+}
+
+void transCtxMerge(STransCtx* dst, STransCtx* src) {
+  if (dst->args == NULL) {
+    dst->args = src->args;
+    src->args = NULL;
+    return;
+  }
+  void*  key = NULL;
+  size_t klen = 0;
+  void*  iter = taosHashIterate(src->args, NULL);
+  while (iter) {
+    STransCtxVal* sVal = (STransCtxVal*)iter;
+    key = taosHashGetKey(sVal, &klen);
+
+    STransCtxVal* dVal = taosHashGet(dst->args, key, klen);
+    if (dVal) {
+      dVal->free(dVal->val);
+    }
+    taosHashPut(dst->args, key, klen, sVal, sizeof(*sVal));
+    iter = taosHashIterate(src->args, iter);
+  }
+  taosHashCleanup(src->args);
+}
+void* transCtxDumpVal(STransCtx* ctx, int32_t key) {
+  if (ctx->args == NULL) {
+    return NULL;
+  }
+  STransCtxVal* cVal = taosHashGet(ctx->args, (const void*)&key, sizeof(key));
+  if (cVal == NULL) {
+    return NULL;
+  }
+  char* ret = calloc(1, cVal->len);
+  memcpy(ret, (char*)cVal->val, cVal->len);
+  return (void*)ret;
+}
+
 #endif
diff --git a/source/libs/transport/src/transSrv.c b/source/libs/transport/src/transSrv.c
index 73d836319fcabd96fc42790b391fb39d8a6a154d..108b12542c1b89f5672f60f5242d8f98cd6baf70 100644
--- a/source/libs/transport/src/transSrv.c
+++ b/source/libs/transport/src/transSrv.c
@@ -17,6 +17,12 @@
 
 #include "transComm.h"
 
+typedef struct {
+  int       notifyCount;  //
+  int       init;         // init or not
+  STransMsg msg;
+} SSrvRegArg;
+
 typedef struct SSrvConn {
   T_REF_DECLARE()
   uv_tcp_t*  pTcp;
@@ -33,8 +39,10 @@ typedef struct SSrvConn {
   void*       hostThrd;
   SArray*     srvMsgs;
 
-  bool broken;  // conn broken;
+  SSrvRegArg regArg;
+  bool       broken;  // conn broken;
 
+  ConnStatus         status;
   struct sockaddr_in addr;
   struct sockaddr_in locaddr;
 
@@ -47,18 +55,18 @@ typedef struct SSrvConn {
 } SSrvConn;
 
 typedef struct SSrvMsg {
-  SSrvConn* pConn;
-  STransMsg msg;
-  queue     q;
+  SSrvConn*     pConn;
+  STransMsg     msg;
+  queue         q;
+  STransMsgType type;
 } SSrvMsg;
 
 typedef struct SWorkThrdObj {
-  pthread_t   thread;
-  uv_pipe_t*  pipe;
-  uv_os_fd_t  fd;
-  uv_loop_t*  loop;
-  SAsyncPool* asyncPool;
-
+  pthread_t       thread;
+  uv_pipe_t*      pipe;
+  uv_os_fd_t      fd;
+  uv_loop_t*      loop;
+  SAsyncPool*     asyncPool;
   queue           msg;
   pthread_mutex_t msgMtx;
 
@@ -85,6 +93,15 @@ typedef struct SServerObj {
 
 static const char* notify = "a";
 
+#define CONN_SHOULD_RELEASE(conn, head)                            \
+  do {                                                             \
+    if ((head)->release == 1 && (head->msgLen) == sizeof(*head)) { \
+      conn->status = ConnRelease;                                  \
+      transClearBuffer(&conn->readBuf);                            \
+      transFreeMsg(transContFromHead((char*)head));                \
+      goto _RETURE;                                                \
+    }                                                              \
+  } while (0)
 // refactor later
 static int transAddAuthPart(SSrvConn* pConn, char* msg, int msgLen);
 
@@ -113,6 +130,13 @@ static void destroySmsg(SSrvMsg* smsg);
 static SSrvConn* createConn(void* hThrd);
 static void      destroyConn(SSrvConn* conn, bool clear /*clear handle or not*/);
 
+static void uvHandleQuit(SSrvMsg* msg, SWorkThrdObj* thrd);
+static void uvHandleRelease(SSrvMsg* msg, SWorkThrdObj* thrd);
+static void uvHandleSendResp(SSrvMsg* msg, SWorkThrdObj* thrd);
+static void uvHandleRegister(SSrvMsg* msg, SWorkThrdObj* thrd);
+static void (*transAsyncHandle[])(SSrvMsg* msg, SWorkThrdObj* thrd) = {uvHandleSendResp, uvHandleQuit, uvHandleRelease,
+                                                                       uvHandleRegister};
+
 static void uvDestroyConn(uv_handle_t* handle);
 
 // server and worker thread
@@ -217,8 +241,8 @@ static void uvHandleReq(SSrvConn* pConn) {
     if (pHead->secured == 1) {
       pHead->msgLen -= sizeof(STransUserMsg);
     }
-    //
   }
+  CONN_SHOULD_RELEASE(pConn, pHead);
 
   STransMsg transMsg;
   transMsg.contLen = transContLenFromMsg(pHead->msgLen);
@@ -230,24 +254,34 @@ static void uvHandleReq(SSrvConn* pConn) {
 
   transClearBuffer(&pConn->readBuf);
   pConn->inType = pHead->msgType;
-
-  if (pHead->resflag == 0) {
+  if (pConn->status == ConnNormal) {
+    if (pHead->persist == 1) {
+      pConn->status = ConnAcquire;
+      transRefSrvHandle(pConn);
+    }
+  }
+  if (pConn->status == ConnNormal && pHead->noResp == 0) {
     transRefSrvHandle(pConn);
-    transMsg.handle = pConn;
     tDebug("server conn %p %s received from %s:%d, local info: %s:%d, msg size: %d", pConn, TMSG_INFO(transMsg.msgType),
            taosInetNtoa(pConn->addr.sin_addr), ntohs(pConn->addr.sin_port), taosInetNtoa(pConn->locaddr.sin_addr),
            ntohs(pConn->locaddr.sin_port), transMsg.contLen);
   } else {
-    tDebug("server conn %p %s received from %s:%d, local info: %s:%d, msg size: %d, no resp ", pConn,
+    tDebug("server conn %p %s received from %s:%d, local info: %s:%d, msg size: %d, resp:%d ", pConn,
            TMSG_INFO(transMsg.msgType), taosInetNtoa(pConn->addr.sin_addr), ntohs(pConn->addr.sin_port),
-           taosInetNtoa(pConn->locaddr.sin_addr), ntohs(pConn->locaddr.sin_port), transMsg.contLen);
+           taosInetNtoa(pConn->locaddr.sin_addr), ntohs(pConn->locaddr.sin_port), transMsg.contLen, pHead->noResp);
+    // no ref here
+  }
+
+  if (pHead->noResp == 0) {
+    transMsg.handle = pConn;
   }
 
   STrans* pTransInst = (STrans*)p->shandle;
   (*pTransInst->cfp)(pTransInst->parent, &transMsg, NULL);
   // uv_timer_start(&pConn->pTimer, uvHandleActivityTimeout, pRpc->idleTime * 10000, 0);
   // auth
-  // validate msg type
+_RETURE:
+  return;
 }
 
 void uvOnRecvCb(uv_stream_t* cli, ssize_t nread, const uv_buf_t* buf) {
@@ -272,11 +306,13 @@ void uvOnRecvCb(uv_stream_t* cli, ssize_t nread, const uv_buf_t* buf) {
   tError("server conn %p read error: %s", conn, uv_err_name(nread));
   if (nread < 0) {
     conn->broken = true;
-    uvNotifyLinkBrokenToApp(conn);
-
-    // STrans* pTransInst = conn->pTransInst;
-    // if (pTransInst->efp != NULL && (pTransInst->efp)(NULL, conn->inType)) {
-    //}
+    if (conn->status == ConnAcquire) {
+      if (conn->regArg.init) {
+        STrans* pTransInst = conn->pTransInst;
+        (*pTransInst->cfp)(pTransInst->parent, &(conn->regArg.msg), NULL);
+        memset(&conn->regArg, 0, sizeof(conn->regArg));
+      }
+    }
     transUnrefSrvHandle(conn);
   }
 }
@@ -301,8 +337,22 @@ void uvOnSendCb(uv_write_t* req, int status) {
       SSrvMsg* msg = taosArrayGetP(conn->srvMsgs, 0);
       tTrace("server conn %p sending msg size: %d", conn, (int)taosArrayGetSize(conn->srvMsgs));
       taosArrayRemove(conn->srvMsgs, 0);
+      if (msg->type == Release && conn->status != ConnNormal) {
+        conn->status = ConnNormal;
+        transUnrefSrvHandle(conn);
+      } else if (msg->type == Register && conn->status == ConnAcquire) {
+        conn->regArg.notifyCount = 0;
+        conn->regArg.init = 1;
+        conn->regArg.msg = msg->msg;
+        if (conn->broken) {
+          STrans* pTransInst = conn->pTransInst;
+          (pTransInst->cfp)(pTransInst->parent, &(conn->regArg.msg), NULL);
+          memset(&conn->regArg, 0, sizeof(conn->regArg));
+        }
+        free(msg);
+        return;
+      }
       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));
@@ -312,7 +362,7 @@ void uvOnSendCb(uv_write_t* req, int status) {
     }
   } else {
     tError("server conn %p failed to write data, %s", conn, uv_err_name(status));
-    conn->broken = false;
+    conn->broken = true;
     transUnrefSrvHandle(conn);
   }
 }
@@ -339,6 +389,7 @@ static void uvPrepareSendData(SSrvMsg* smsg, uv_buf_t* wb) {
 
   pHead->secured = pMsg->code == 0 ? 1 : 0;  //
   pHead->msgType = smsg->pConn->inType + 1;
+  pHead->release = smsg->type == Release ? 1 : 0;
   pHead->code = htonl(pMsg->code);
   // add more info
   char*   msg = (char*)pHead;
@@ -368,13 +419,16 @@ static void uvStartSendResp(SSrvMsg* smsg) {
   SSrvConn* pConn = smsg->pConn;
 
   if (pConn->broken == true) {
+    // persist by
     transUnrefSrvHandle(pConn);
     return;
   }
-  transUnrefSrvHandle(pConn);
+  if (pConn->status == ConnNormal) {
+    transUnrefSrvHandle(pConn);
+  }
 
   if (taosArrayGetSize(pConn->srvMsgs) > 0) {
-    tDebug("server conn %p push data to client %s:%d, local info: %s:%d", pConn, taosInetNtoa(pConn->addr.sin_addr),
+    tDebug("server conn %p send data to client %s:%d, local info: %s:%d", pConn, taosInetNtoa(pConn->addr.sin_addr),
            ntohs(pConn->addr.sin_port), taosInetNtoa(pConn->locaddr.sin_addr), ntohs(pConn->locaddr.sin_port));
     taosArrayPush(pConn->srvMsgs, &smsg);
     return;
@@ -384,16 +438,6 @@ static void uvStartSendResp(SSrvMsg* smsg) {
   return;
 }
 
-static void uvNotifyLinkBrokenToApp(SSrvConn* conn) {
-  STrans* pTransInst = conn->pTransInst;
-  if (pTransInst->efp != NULL && (*pTransInst->efp)(NULL, conn->inType) && T_REF_VAL_GET(conn) >= 2) {
-    STransMsg transMsg = {0};
-    transMsg.msgType = conn->inType;
-    transMsg.code = TSDB_CODE_RPC_NETWORK_UNAVAIL;
-    // transRefSrvHandle(conn);
-    (*pTransInst->cfp)(pTransInst->parent, &transMsg, 0);
-  }
-}
 static void destroySmsg(SSrvMsg* smsg) {
   if (smsg == NULL) {
     return;
@@ -408,6 +452,9 @@ static void destroyAllConn(SWorkThrdObj* pThrd) {
     QUEUE_INIT(h);
 
     SSrvConn* c = QUEUE_DATA(h, SSrvConn, queue);
+    while (T_REF_VAL_GET(c) >= 2) {
+      transUnrefSrvHandle(c);
+    }
     transUnrefSrvHandle(c);
   }
 }
@@ -431,20 +478,7 @@ void uvWorkerAsyncCb(uv_async_t* handle) {
       tError("unexcept occurred, continue");
       continue;
     }
-    if (msg->pConn == NULL) {
-      free(msg);
-      bool noConn = QUEUE_IS_EMPTY(&pThrd->conn);
-      if (noConn == true) {
-        uv_loop_close(pThrd->loop);
-        uv_stop(pThrd->loop);
-      } else {
-        destroyAllConn(pThrd);
-        // uv_loop_close(pThrd->loop);
-        pThrd->quit = true;
-      }
-    } else {
-      uvStartSendResp(msg);
-    }
+    (*transAsyncHandle[msg->type])(msg, pThrd);
   }
 }
 static void uvAcceptAsyncCb(uv_async_t* async) {
@@ -632,7 +666,9 @@ static SSrvConn* createConn(void* hThrd) {
   pConn->srvMsgs = taosArrayInit(2, sizeof(void*));  //
   tTrace("conn %p created", pConn);
 
+  memset(&pConn->regArg, 0, sizeof(pConn->regArg));
   pConn->broken = false;
+  pConn->status = ConnNormal;
 
   transRefSrvHandle(pConn);
   return pConn;
@@ -748,7 +784,58 @@ End:
   transCloseServer(srv);
   return NULL;
 }
-
+void uvHandleQuit(SSrvMsg* msg, SWorkThrdObj* thrd) {
+  if (QUEUE_IS_EMPTY(&thrd->conn)) {
+    uv_loop_close(thrd->loop);
+    uv_stop(thrd->loop);
+  } else {
+    destroyAllConn(thrd);
+    thrd->quit = true;
+  }
+  free(msg);
+}
+void uvHandleRelease(SSrvMsg* msg, SWorkThrdObj* thrd) {
+  // release handle to rpc init
+  SSrvConn* conn = msg->pConn;
+  if (conn->status == ConnAcquire) {
+    if (taosArrayGetSize(conn->srvMsgs) > 0) {
+      taosArrayPush(conn->srvMsgs, &msg);
+      return;
+    }
+    taosArrayPush(conn->srvMsgs, &msg);
+    uvStartSendRespInternal(msg);
+    return;
+  } else if (conn->status == ConnRelease) {
+    // already release by server app, do nothing
+  } else if (conn->status == ConnNormal) {
+    // no nothing
+    // user should not call this rpcRelease handle;
+  }
+  free(msg);
+}
+void uvHandleSendResp(SSrvMsg* msg, SWorkThrdObj* thrd) {
+  // send msg to client
+  uvStartSendResp(msg);
+}
+void uvHandleRegister(SSrvMsg* msg, SWorkThrdObj* thrd) {
+  SSrvConn* conn = msg->pConn;
+  if (conn->status == ConnAcquire) {
+    if (taosArrayGetSize(conn->srvMsgs) > 0) {
+      taosArrayPush(conn->srvMsgs, &msg);
+      return;
+    }
+    conn->regArg.notifyCount = 0;
+    conn->regArg.init = 1;
+    conn->regArg.msg = msg->msg;
+
+    if (conn->broken) {
+      STrans* pTransInst = conn->pTransInst;
+      (*pTransInst->cfp)(pTransInst->parent, &(conn->regArg.msg), NULL);
+      memset(&conn->regArg, 0, sizeof(conn->regArg));
+    }
+    free(msg);
+  }
+}
 void destroyWorkThrd(SWorkThrdObj* pThrd) {
   if (pThrd == NULL) {
     return;
@@ -759,10 +846,10 @@ void destroyWorkThrd(SWorkThrdObj* pThrd) {
   free(pThrd);
 }
 void sendQuitToWorkThrd(SWorkThrdObj* pThrd) {
-  SSrvMsg* srvMsg = calloc(1, sizeof(SSrvMsg));
+  SSrvMsg* msg = calloc(1, sizeof(SSrvMsg));
+  msg->type = Quit;
   tDebug("server send quit msg to work thread");
-
-  transSendAsync(pThrd->asyncPool, &srvMsg->q);
+  transSendAsync(pThrd->asyncPool, &msg->q);
 }
 
 void transCloseServer(void* arg) {
@@ -813,8 +900,21 @@ void transUnrefSrvHandle(void* handle) {
 }
 
 void transReleaseSrvHandle(void* handle) {
-  // do nothing currently
-  //
+  if (handle == NULL) {
+    return;
+  }
+  SSrvConn*     pConn = handle;
+  SWorkThrdObj* pThrd = pConn->hostThrd;
+
+  STransMsg tmsg = {.handle = handle, .code = 0};
+
+  SSrvMsg* srvMsg = calloc(1, sizeof(SSrvMsg));
+  srvMsg->msg = tmsg;
+  srvMsg->type = Release;
+  srvMsg->pConn = pConn;
+
+  tTrace("server conn %p start to release", pConn);
+  transSendAsync(pThrd->asyncPool, &srvMsg->q);
 }
 void transSendResponse(const STransMsg* pMsg) {
   if (pMsg->handle == NULL) {
@@ -826,6 +926,21 @@ void transSendResponse(const STransMsg* pMsg) {
   SSrvMsg* srvMsg = calloc(1, sizeof(SSrvMsg));
   srvMsg->pConn = pConn;
   srvMsg->msg = *pMsg;
+  srvMsg->type = Normal;
+  tTrace("server conn %p start to send resp", pConn);
+  transSendAsync(pThrd->asyncPool, &srvMsg->q);
+}
+void transRegisterMsg(const STransMsg* msg) {
+  if (msg->handle == NULL) {
+    return;
+  }
+  SSrvConn*     pConn = msg->handle;
+  SWorkThrdObj* pThrd = pConn->hostThrd;
+
+  SSrvMsg* srvMsg = calloc(1, sizeof(SSrvMsg));
+  srvMsg->pConn = pConn;
+  srvMsg->msg = *msg;
+  srvMsg->type = Register;
   tTrace("server conn %p start to send resp", pConn);
   transSendAsync(pThrd->asyncPool, &srvMsg->q);
 }
diff --git a/source/libs/transport/test/transUT.cc b/source/libs/transport/test/transUT.cc
index ec89d695a2bac264b4ee1f844c3baa7752c046f5..deccd633d8a0e929a0a72fbfdaf07170814a6d7e 100644
--- a/source/libs/transport/test/transUT.cc
+++ b/source/libs/transport/test/transUT.cc
@@ -31,11 +31,6 @@ 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;
@@ -91,21 +86,8 @@ class Client {
     rpcClose(this->transCli);
     this->transCli = NULL;
   }
-  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)) {
     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)) {
-    rpcClose(this->transCli);
-
-    rpcInit_.pfp = pfp;
-    rpcInit_.mfp = mfp;
     this->transCli = rpcOpen(&rpcInit_);
   }
 
@@ -149,7 +131,6 @@ class Server {
     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;
@@ -165,11 +146,6 @@ class Server {
     rpcClose(this->transSrv);
     this->transSrv = NULL;
   }
-  void SetExceptFp(bool (*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;
@@ -262,23 +238,11 @@ class TransObj {
     //
     srv->Stop();
   }
-  void SetCliPersistFp(bool (*pfp)(void *parent, tmsg_t msgType)) {
-    // do nothing
-    cli->SetPersistFP(pfp);
-  }
   void SetCliMFp(void *(*mfp)(void *parent, tmsg_t msgType)) {
     // do nothing
     cli->SetConstructFP(mfp);
   }
-  void SetCliMAndPFp(bool (*pfp)(void *parent, tmsg_t msgType), void *(*mfp)(void *parent, tmsg_t msgType)) {
-    // do nothing
-    cli->SetPAndMFp(pfp, mfp);
-  }
   // call when link broken, and notify query or fetch stop
-  void SetSrvExceptFp(bool (*efp)(void *parent, tmsg_t msgType)) {
-    ////////
-    srv->SetExceptFp(efp);
-  }
   void SetSrvContinueSend(void (*cfp)(void *parent, SRpcMsg *pMsg, SEpSet *pEpSet)) {
     ///////
     srv->SetSrvContinueSend(cfp);
@@ -358,10 +322,10 @@ TEST_F(TransEnv, clientUserDefined) {
 }
 
 TEST_F(TransEnv, cliPersistHandle) {
-  tr->SetCliPersistFp(cliPersistHandle);
+  // tr->SetCliPersistFp(cliPersistHandle);
   SRpcMsg resp = {0};
   for (int i = 0; i < 10; i++) {
-    SRpcMsg req = {.handle = resp.handle, .noResp = 0};
+    SRpcMsg req = {.handle = resp.handle, .persistHandle = 1};
     req.msgType = 1;
     req.pCont = rpcMallocCont(10);
     req.contLen = 10;
@@ -378,31 +342,22 @@ TEST_F(TransEnv, cliPersistHandle) {
 }
 
 TEST_F(TransEnv, cliReleaseHandle) {
-  tr->SetCliPersistFp(cliPersistHandle);
-
   SRpcMsg resp = {0};
   for (int i = 0; i < 10; i++) {
-    SRpcMsg req = {.handle = resp.handle};
+    SRpcMsg req = {.handle = resp.handle, .persistHandle = 1};
     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};
+    SRpcMsg req = {.handle = resp.handle, .persistHandle = 1};
     req.msgType = 1;
     req.pCont = rpcMallocCont(10);
     req.contLen = 10;
@@ -431,7 +386,7 @@ TEST_F(TransEnv, srvContinueSend) {
 
 TEST_F(TransEnv, srvPersistHandleExcept) {
   tr->SetSrvContinueSend(processContinueSend);
-  tr->SetCliPersistFp(cliPersistHandle);
+  // tr->SetCliPersistFp(cliPersistHandle);
   SRpcMsg resp = {0};
   for (int i = 0; i < 5; i++) {
     SRpcMsg req = {.handle = resp.handle};
@@ -450,7 +405,6 @@ TEST_F(TransEnv, srvPersistHandleExcept) {
 }
 TEST_F(TransEnv, cliPersistHandleExcept) {
   tr->SetSrvContinueSend(processContinueSend);
-  tr->SetCliPersistFp(cliPersistHandle);
   SRpcMsg resp = {0};
   for (int i = 0; i < 5; i++) {
     SRpcMsg req = {.handle = resp.handle};
@@ -472,7 +426,7 @@ TEST_F(TransEnv, multiCliPersistHandleExcept) {
   // conn broken
 }
 TEST_F(TransEnv, queryExcept) {
-  tr->SetSrvExceptFp(handleExcept);
+  // tr->SetSrvExceptFp(handleExcept);
 
   // query and conn is broken
 }
diff --git a/source/libs/transport/test/transportTests.cc b/source/libs/transport/test/transportTests.cc
index 53910aa30c1d7bcea1ce0d6dc46f1bb579c3c3c1..1f8c8e8ff20d3ae57d120e02dfd04c8e5a84850d 100644
--- a/source/libs/transport/test/transportTests.cc
+++ b/source/libs/transport/test/transportTests.cc
@@ -136,4 +136,98 @@ TEST_F(QueueEnv, testIter) {
   assert(result.size() == vals.size());
 }
 
+class TransCtxEnv : public ::testing::Test {
+ protected:
+  virtual void SetUp() {
+    ctx = (STransCtx *)calloc(1, sizeof(STransCtx));
+    transCtxInit(ctx);
+    // TODO
+  }
+  virtual void TearDown() {
+    transCtxDestroy(ctx);
+    // formate
+  }
+  STransCtx *ctx;
+};
+
+TEST_F(TransCtxEnv, mergeTest) {
+  int key = 1;
+  {
+    STransCtx *src = (STransCtx *)calloc(1, sizeof(STransCtx));
+    transCtxInit(src);
+    {
+      STransCtxVal val1 = {.val = NULL, .len = 0, .free = free};
+      val1.val = malloc(12);
+      val1.len = 12;
+
+      taosHashPut(src->args, &key, sizeof(key), &val1, sizeof(val1));
+      key++;
+    }
+    {
+      STransCtxVal val1 = {.val = NULL, .len = 0, .free = free};
+      val1.val = malloc(12);
+      val1.len = 12;
+      taosHashPut(src->args, &key, sizeof(key), &val1, sizeof(val1));
+      key++;
+    }
+    transCtxMerge(ctx, src);
+    free(src);
+  }
+  EXPECT_EQ(2, taosHashGetSize(ctx->args));
+  {
+    STransCtx *src = (STransCtx *)calloc(1, sizeof(STransCtx));
+    transCtxInit(src);
+    {
+      STransCtxVal val1 = {.val = NULL, .len = 0, .free = free};
+      val1.val = malloc(12);
+      val1.len = 12;
+
+      taosHashPut(src->args, &key, sizeof(key), &val1, sizeof(val1));
+      key++;
+    }
+    {
+      STransCtxVal val1 = {.val = NULL, .len = 0, .free = free};
+      val1.val = malloc(12);
+      val1.len = 12;
+      taosHashPut(src->args, &key, sizeof(key), &val1, sizeof(val1));
+      key++;
+    }
+    transCtxMerge(ctx, src);
+    free(src);
+  }
+  std::string val("Hello");
+  EXPECT_EQ(4, taosHashGetSize(ctx->args));
+  {
+    key = 1;
+    STransCtx *src = (STransCtx *)calloc(1, sizeof(STransCtx));
+    transCtxInit(src);
+    {
+      STransCtxVal val1 = {.val = NULL, .len = 0, .free = free};
+      val1.val = calloc(1, 11);
+      memcpy(val1.val, val.c_str(), val.size());
+      val1.len = 11;
+
+      taosHashPut(src->args, &key, sizeof(key), &val1, sizeof(val1));
+      key++;
+    }
+    {
+      STransCtxVal val1 = {.val = NULL, .len = 0, .free = free};
+      val1.val = calloc(1, 11);
+      memcpy(val1.val, val.c_str(), val.size());
+      val1.len = 11;
+      taosHashPut(src->args, &key, sizeof(key), &val1, sizeof(val1));
+      key++;
+    }
+    transCtxMerge(ctx, src);
+    free(src);
+  }
+  EXPECT_EQ(4, taosHashGetSize(ctx->args));
+
+  char *skey = (char *)transCtxDumpVal(ctx, 1);
+  EXPECT_EQ(0, strcmp(skey, val.c_str()));
+  free(skey);
+
+  skey = (char *)transCtxDumpVal(ctx, 2);
+  EXPECT_EQ(0, strcmp(skey, val.c_str()));
+}
 #endif