diff --git a/source/client/inc/clientInt.h b/source/client/inc/clientInt.h
index a34250ccab8f51355e0318bfc65d248234cb4d7e..550d8c3ecfe96b0268ce739c2a5d146913024a21 100644
--- a/source/client/inc/clientInt.h
+++ b/source/client/inc/clientInt.h
@@ -37,7 +37,7 @@ typedef struct SQueryExecMetric {
   int64_t      rsp;      // receive response from server
 } SQueryExecMetric;
 
-typedef struct SInstanceActivity {
+typedef struct SInstanceSummary {
   uint64_t     numOfInsertsReq;
   uint64_t     numOfInsertRows;
   uint64_t     insertElapsedTime;
@@ -48,7 +48,7 @@ typedef struct SInstanceActivity {
   uint64_t     numOfSlowQueries;
   uint64_t     totalRequests;
   uint64_t     currentRequests;      // the number of SRequestObj
-} SInstanceActivity;
+} SInstanceSummary;
 
 typedef struct SHeartBeatInfo {
   void  *pTimer;   // timer, used to send request msg to mnode
@@ -57,7 +57,7 @@ typedef struct SHeartBeatInfo {
 typedef struct SAppInstInfo {
   int64_t           numOfConns;
   SCorEpSet         mgmtEp;
-  SInstanceActivity summary;
+  SInstanceSummary  summary;
   SList            *pConnList;  // STscObj linked list
   uint32_t          clusterId;
   void             *pTransporter;
@@ -100,16 +100,16 @@ typedef struct SReqResultInfo {
   uint32_t     current;
 } SReqResultInfo;
 
-typedef struct SReqMsg {
-  void     *pMsg;
+typedef struct SDataBuf {
+  void     *pData;
   uint32_t  len;
-} SReqMsgInfo;
+} SDataBuf;
 
 typedef struct SRequestSendRecvBody {
   tsem_t          rspSem;        // not used now
   void*           fp;
   int64_t         execId;        // showId/queryId
-  SReqMsgInfo     requestMsg;
+  SDataBuf        requestMsg;
   SReqResultInfo  resInfo;
 } SRequestSendRecvBody;
 
@@ -121,26 +121,38 @@ typedef struct SRequestObj {
   STscObj         *pTscObj;
   SQueryExecMetric metric;
   char            *sqlstr;  // sql string
-  SRequestSendRecvBody     body;
+  SRequestSendRecvBody body;
   int64_t          self;
   char            *msgBuf;
-  int32_t          code;
   void            *pInfo;   // sql parse info, generated by parser module
+  int32_t          code;
 } SRequestObj;
 
 typedef struct SRequestMsgBody {
   int32_t     msgType;
-  SReqMsgInfo msgInfo;
+  SDataBuf    msgInfo;
   uint64_t    requestId;
   uint64_t    requestObjRefId;
 } SRequestMsgBody;
 
-extern SAppInfo   appInfo;
-extern int32_t    tscReqRef;
-extern int32_t    tscConnRef;
+typedef int (*__async_send_cb_fn_t)(void* param, const SDataBuf* pMsg, int32_t code);
+
+typedef struct SMsgSendInfo {
+  __async_send_cb_fn_t    fp;
+  void    *param;
+  uint64_t requestId;
+  uint64_t requestObjRefId;
+  int32_t  msgType;
+  SDataBuf msgInfo;
+} SMsgSendInfo;
+
+extern SAppInfo appInfo;
+extern int32_t  msgObjRefPool;
+extern int32_t  clientConnRefPool;
 
-SRequestMsgBody buildRequestMsgImpl(SRequestObj *pRequest);
-extern int (*handleRequestRspFp[TSDB_MSG_TYPE_MAX])(SRequestObj *pRequest, const char* pMsg, int32_t msgLen);
+SMsgSendInfo* buildSendMsgInfoImpl(SRequestObj *pRequest);
+int genericExecCallback(void* param, const SDataBuf* pMsg, int32_t code);
+extern int (*handleRequestRspFp[TSDB_MSG_TYPE_MAX])(void* param, const SDataBuf* pMsg, int32_t code);
 
 int   taos_init();
 
diff --git a/source/client/src/clientEnv.c b/source/client/src/clientEnv.c
index b54f7fedd788ea464714c17f033ac5b1bac48244..dca4d85ad6c707f16ff31d66fde4d4adc1959b13 100644
--- a/source/client/src/clientEnv.c
+++ b/source/client/src/clientEnv.c
@@ -13,10 +13,10 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <catalog.h>
+#include "os.h"
+#include "catalog.h"
 #include "clientInt.h"
 #include "clientLog.h"
-#include "os.h"
 #include "query.h"
 #include "taosmsg.h"
 #include "tcache.h"
@@ -32,26 +32,26 @@
 #define TSC_VAR_RELEASED    0
 
 SAppInfo   appInfo;
-int32_t    tscReqRef  = -1;
-int32_t    tscConnRef = -1;
+int32_t    msgObjRefPool  = -1;
+int32_t    clientConnRefPool = -1;
 
 static pthread_once_t tscinit = PTHREAD_ONCE_INIT;
 volatile int32_t tscInitRes = 0;
 
 static void registerRequest(SRequestObj* pRequest) {
-  STscObj *pTscObj = (STscObj *)taosAcquireRef(tscConnRef, pRequest->pTscObj->id);
+  STscObj *pTscObj = (STscObj *)taosAcquireRef(clientConnRefPool, pRequest->pTscObj->id);
   assert(pTscObj != NULL);
 
   // connection has been released already, abort creating request.
-  pRequest->self = taosAddRef(tscReqRef, pRequest);
+  pRequest->self = taosAddRef(msgObjRefPool, pRequest);
 
   int32_t num = atomic_add_fetch_32(&pTscObj->numOfReqs, 1);
 
   if (pTscObj->pAppInfo) {
-    SInstanceActivity *pActivity = &pTscObj->pAppInfo->summary;
+    SInstanceSummary *pSummary = &pTscObj->pAppInfo->summary;
 
-    int32_t total = atomic_add_fetch_32(&pActivity->totalRequests, 1);
-    int32_t currentInst = atomic_add_fetch_32(&pActivity->currentRequests, 1);
+    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", pRequest->self,
              pRequest->pTscObj->id, num, currentInst, total);
   }
@@ -61,13 +61,13 @@ static void deregisterRequest(SRequestObj* pRequest) {
   assert(pRequest != NULL);
 
   STscObj* pTscObj = pRequest->pTscObj;
-  SInstanceActivity* pActivity = &pTscObj->pAppInfo->summary;
+  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);
 
   tscDebug("0x%"PRIx64" free Request from connObj: 0x%"PRIx64", current:%d, app current:%d", pRequest->self, pTscObj->id, num, currentInst);
-  taosReleaseRef(tscConnRef, pTscObj->id);
+  taosReleaseRef(clientConnRefPool, pTscObj->id);
 }
 
 static void tscInitLogFile() {
@@ -150,7 +150,7 @@ void* createTscObj(const char* user, const char* auth, const char *db, SAppInstI
   }
 
   pthread_mutex_init(&pObj->mutex, NULL);
-  pObj->id = taosAddRef(tscConnRef, pObj);
+  pObj->id = taosAddRef(clientConnRefPool, pObj);
 
   tscDebug("connObj created, 0x%"PRIx64, pObj->id);
   return pObj;
@@ -173,7 +173,6 @@ void* createRequest(STscObj* pObj, __taos_async_fn_t fp, void* param, int32_t ty
   pRequest->type       = type;
   pRequest->pTscObj    = pObj;
   pRequest->body.fp    = fp;
-//  pRequest->body.requestMsg. = param;
   pRequest->msgBuf     = calloc(1, ERROR_MSG_BUF_DEFAULT_SIZE);
   tsem_init(&pRequest->body.rspSem, 0, 0);
 
@@ -202,7 +201,7 @@ void destroyRequest(SRequestObj* pRequest) {
     return;
   }
 
-  taosReleaseRef(tscReqRef, pRequest->self);
+  taosReleaseRef(msgObjRefPool, pRequest->self);
 }
 
 void taos_init_imp(void) {
@@ -238,8 +237,8 @@ void taos_init_imp(void) {
 
   initTaskQueue();
 
-  tscConnRef = taosOpenRef(200, destroyTscObj);
-  tscReqRef  = taosOpenRef(40960, doDestroyRequest);
+  clientConnRefPool = taosOpenRef(200, destroyTscObj);
+  msgObjRefPool  = taosOpenRef(40960, doDestroyRequest);
 
   taosGetAppName(appInfo.appName, NULL);
   appInfo.pid       = taosGetPId();
diff --git a/source/client/src/clientImpl.c b/source/client/src/clientImpl.c
index f00e7bd5781ce8f04e3f67410e08f9b44f6b2d39..7cd8e9d359bc2bf8a2ef331d51ec5a62ff66d2af 100644
--- a/source/client/src/clientImpl.c
+++ b/source/client/src/clientImpl.c
@@ -11,10 +11,10 @@
 #include "parser.h"
 
 static int32_t initEpSetFromCfg(const char *firstEp, const char *secondEp, SCorEpSet *pEpSet);
-static int32_t buildConnectMsg(SRequestObj *pRequest, SRequestMsgBody* pMsgBody);
-static void destroyRequestMsgBody(SRequestMsgBody* pMsgBody);
+static SMsgSendInfo* buildConnectMsg(SRequestObj *pRequest);
+static void destroySendMsgInfo(SMsgSendInfo* pMsgBody);
 
-static int32_t sendMsgToServer(void *pTransporter, SEpSet* epSet, const SRequestMsgBody *pBody, int64_t* pTransporterId);
+static int32_t sendMsgToServer(void *pTransporter, SEpSet* epSet, int64_t* pTransporterId, const SMsgSendInfo* pInfo);
 
 static bool stringLengthCheck(const char* str, size_t maxsize) {
   if (str == NULL) {
@@ -163,10 +163,11 @@ TAOS_RES *taos_query_l(TAOS *taos, const char *sql, int sqlLen) {
   int32_t code = qParseQuerySql(&cxt, &pQuery);
   if (qIsDclQuery(pQuery)) {
     SDclStmtInfo* pDcl = (SDclStmtInfo*) pQuery;
+
     pRequest->type = pDcl->msgType;
-    pRequest->body.requestMsg = (SReqMsgInfo){.pMsg = pDcl->pMsg, .len = pDcl->msgLen};
+    pRequest->body.requestMsg = (SDataBuf){.pData = pDcl->pMsg, .len = pDcl->msgLen};
 
-    SRequestMsgBody body = buildRequestMsgImpl(pRequest);
+    SMsgSendInfo* body = buildSendMsgInfoImpl(pRequest);
     SEpSet* pEpSet = &pTscObj->pAppInfo->mgmtEp.epSet;
 
     if (pDcl->msgType == TSDB_MSG_TYPE_CREATE_TABLE) {
@@ -180,7 +181,7 @@ TAOS_RES *taos_query_l(TAOS *taos, const char *sql, int sqlLen) {
         return pRequest;
       }
 
-      SCreateTableMsg* pMsg = body.msgInfo.pMsg;
+      SCreateTableMsg* pMsg = body->msgInfo.pData;
 
       SName t = {0};
       tNameFromString(&t, pMsg->name, T_NAME_ACCT|T_NAME_DB|T_NAME_TABLE);
@@ -200,14 +201,14 @@ TAOS_RES *taos_query_l(TAOS *taos, const char *sql, int sqlLen) {
         tstrncpy(ep.fqdn[i], info.epAddr[i].fqdn, tListLen(ep.fqdn[i]));
       }
 
-      sendMsgToServer(pTscObj->pTransporter, &ep, &body, &transporterId);
+      sendMsgToServer(pTscObj->pTransporter, &ep, &transporterId, body);
     } else {
       int64_t transporterId = 0;
-      sendMsgToServer(pTscObj->pTransporter, pEpSet, &body, &transporterId);
+      sendMsgToServer(pTscObj->pTransporter, pEpSet, &transporterId, body);
     }
 
     tsem_wait(&pRequest->body.rspSem);
-    destroyRequestMsgBody(&body);
+    destroySendMsgInfo(body);
   }
 
   tfree(cxt.ctx.db);
@@ -270,14 +271,13 @@ STscObj* taosConnectImpl(const char *ip, const char *user, const char *auth, con
     return NULL;
   }
 
-  SRequestMsgBody body = {0};
-  buildConnectMsg(pRequest, &body);
+  SMsgSendInfo* body = buildConnectMsg(pRequest);
 
   int64_t transporterId = 0;
-  sendMsgToServer(pTscObj->pTransporter, &pTscObj->pAppInfo->mgmtEp.epSet, &body, &transporterId);
+  sendMsgToServer(pTscObj->pTransporter, &pTscObj->pAppInfo->mgmtEp.epSet, &transporterId, body);
 
   tsem_wait(&pRequest->body.rspSem);
-  destroyRequestMsgBody(&body);
+  destroySendMsgInfo(body);
 
   if (pRequest->code != TSDB_CODE_SUCCESS) {
     const char *errorMsg = (pRequest->code == TSDB_CODE_RPC_FQDN_ERROR) ? taos_errstr(pRequest) : tstrerror(terrno);
@@ -294,15 +294,25 @@ STscObj* taosConnectImpl(const char *ip, const char *user, const char *auth, con
   return pTscObj;
 }
 
-static int32_t buildConnectMsg(SRequestObj *pRequest, SRequestMsgBody* pMsgBody) {
-  pMsgBody->msgType         = TSDB_MSG_TYPE_CONNECT;
-  pMsgBody->msgInfo.len     = sizeof(SConnectMsg);
-  pMsgBody->requestObjRefId = pRequest->self;
+static SMsgSendInfo* buildConnectMsg(SRequestObj *pRequest) {
+  SMsgSendInfo *pMsgSendInfo = calloc(1, sizeof(SMsgSendInfo));
+  if (pMsgSendInfo == NULL) {
+    terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
+    return NULL;
+  }
+
+  pMsgSendInfo->msgType         = TSDB_MSG_TYPE_CONNECT;
+  pMsgSendInfo->msgInfo.len     = sizeof(SConnectMsg);
+  pMsgSendInfo->requestObjRefId = pRequest->self;
+  pMsgSendInfo->requestId       = pRequest->requestId;
+  pMsgSendInfo->fp              = handleRequestRspFp[pMsgSendInfo->msgType];
+  pMsgSendInfo->param           = pRequest;
 
   SConnectMsg *pConnect = calloc(1, sizeof(SConnectMsg));
   if (pConnect == NULL) {
+    tfree(pMsgSendInfo);
     terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
-    return -1;
+    return NULL;
   }
 
   STscObj *pObj = pRequest->pTscObj;
@@ -315,84 +325,78 @@ static int32_t buildConnectMsg(SRequestObj *pRequest, SRequestMsgBody* pMsgBody)
   pConnect->startTime = htobe64(appInfo.startTime);
   tstrncpy(pConnect->app, appInfo.appName, tListLen(pConnect->app));
 
-  pMsgBody->msgInfo.pMsg = pConnect;
-  return 0;
+  pMsgSendInfo->msgInfo.pData = pConnect;
+  return pMsgSendInfo;
 }
 
-static void destroyRequestMsgBody(SRequestMsgBody* pMsgBody) {
+static void destroySendMsgInfo(SMsgSendInfo* pMsgBody) {
   assert(pMsgBody != NULL);
-  tfree(pMsgBody->msgInfo.pMsg);
+  tfree(pMsgBody->msgInfo.pData);
+  tfree(pMsgBody);
 }
 
-int32_t sendMsgToServer(void *pTransporter, SEpSet* epSet, const SRequestMsgBody *pBody, int64_t* pTransporterId) {
-  char *pMsg = rpcMallocCont(pBody->msgInfo.len);
+int32_t sendMsgToServer(void *pTransporter, SEpSet* epSet, int64_t* pTransporterId, const SMsgSendInfo* pInfo) {
+  char *pMsg = rpcMallocCont(pInfo->msgInfo.len);
   if (NULL == pMsg) {
-    tscError("0x%"PRIx64" msg:%s malloc failed", pBody->requestId, taosMsg[pBody->msgType]);
+    tscError("0x%"PRIx64" msg:%s malloc failed", pInfo->requestId, taosMsg[pInfo->msgType]);
     terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
     return -1;
   }
 
-  memcpy(pMsg, pBody->msgInfo.pMsg, pBody->msgInfo.len);
+  memcpy(pMsg, pInfo->msgInfo.pData, pInfo->msgInfo.len);
   SRpcMsg rpcMsg = {
-      .msgType = pBody->msgType,
+      .msgType = pInfo->msgType,
       .pCont   = pMsg,
-      .contLen = pBody->msgInfo.len,
-      .ahandle = (void*) pBody->requestObjRefId,
+      .contLen = pInfo->msgInfo.len,
+      .ahandle = (void*) pInfo,
       .handle  = NULL,
       .code    = 0
   };
 
+  assert(pInfo->fp != NULL);
+
   rpcSendRequest(pTransporter, epSet, &rpcMsg, pTransporterId);
   return TSDB_CODE_SUCCESS;
 }
 
 void processMsgFromServer(void* parent, SRpcMsg* pMsg, SEpSet* pEpSet) {
-  int64_t requestRefId = (int64_t)pMsg->ahandle;
-
-  SRequestObj *pRequest = (SRequestObj *)taosAcquireRef(tscReqRef, requestRefId);
-  if (pRequest == NULL) {
-    rpcFreeCont(pMsg->pCont);
-    return;
-  }
+  SMsgSendInfo *pSendInfo = (SMsgSendInfo *) pMsg->ahandle;
+  assert(pMsg->ahandle != NULL);
 
-  assert(pRequest->self == requestRefId);
-  pRequest->metric.rsp = taosGetTimestampMs();
+  if (pSendInfo->requestObjRefId != 0) {
+    SRequestObj *pRequest = (SRequestObj *)taosAcquireRef(msgObjRefPool, pSendInfo->requestObjRefId);
+    assert(pRequest->self == pSendInfo->requestObjRefId);
 
-  pRequest->code = pMsg->code;
+    pRequest->metric.rsp = taosGetTimestampMs();
+    pRequest->code = pMsg->code;
 
-  STscObj *pTscObj = pRequest->pTscObj;
-  if (pEpSet) {
-    if (!isEpsetEqual(&pTscObj->pAppInfo->mgmtEp.epSet, pEpSet)) {
-      updateEpSet_s(&pTscObj->pAppInfo->mgmtEp, pEpSet);
+    STscObj *pTscObj = pRequest->pTscObj;
+    if (pEpSet) {
+      if (!isEpsetEqual(&pTscObj->pAppInfo->mgmtEp.epSet, pEpSet)) {
+        updateEpSet_s(&pTscObj->pAppInfo->mgmtEp, pEpSet);
+      }
     }
-  }
 
-  /*
+    /*
    * There is not response callback function for submit response.
    * The actual inserted number of points is the first number.
-   */
-  if (pMsg->code == TSDB_CODE_SUCCESS) {
-    tscDebug("0x%" PRIx64 " message:%s, code:%s rspLen:%d, elapsed:%"PRId64 " ms", pRequest->requestId, taosMsg[pMsg->msgType],
-             tstrerror(pMsg->code), pMsg->contLen, pRequest->metric.rsp - pRequest->metric.start);
-    if (handleRequestRspFp[pRequest->type]) {
-      char *p = malloc(pMsg->contLen);
-      if (p == NULL) {
-        pRequest->code = TSDB_CODE_TSC_OUT_OF_MEMORY;
-        terrno = pRequest->code;
-      } else {
-        memcpy(p, pMsg->pCont, pMsg->contLen);
-        pMsg->code = (*handleRequestRspFp[pRequest->type])(pRequest, p, pMsg->contLen);
-      }
+     */
+    if (pMsg->code == TSDB_CODE_SUCCESS) {
+      tscDebug("0x%" PRIx64 " message:%s, code:%s rspLen:%d, elapsed:%" PRId64 " ms", pRequest->requestId,
+               taosMsg[pMsg->msgType], tstrerror(pMsg->code), pMsg->contLen,
+               pRequest->metric.rsp - pRequest->metric.start);
+    } else {
+      tscError("0x%" PRIx64 " SQL cmd:%s, code:%s rspLen:%d, elapsed time:%" PRId64 " ms", pRequest->requestId,
+               taosMsg[pMsg->msgType], tstrerror(pMsg->code), pMsg->contLen,
+               pRequest->metric.rsp - pRequest->metric.start);
     }
-  } else {
-    tscError("0x%" PRIx64 " SQL cmd:%s, code:%s rspLen:%d, elapsed time:%"PRId64" ms", pRequest->requestId, taosMsg[pMsg->msgType],
-             tstrerror(pMsg->code), pMsg->contLen, pRequest->metric.rsp - pRequest->metric.start);
+
+    taosReleaseRef(msgObjRefPool, pSendInfo->requestObjRefId);
   }
 
-  taosReleaseRef(tscReqRef, requestRefId);
+  SDataBuf buf = {.pData = pMsg->pCont, .len = pMsg->contLen};
+  pSendInfo->fp(pSendInfo->param, &buf, pMsg->code);
   rpcFreeCont(pMsg->pCont);
-
-  sem_post(&pRequest->body.rspSem);
 }
 
 TAOS *taos_connect_auth(const char *ip, const char *user, const char *auth, const char *db, uint16_t port) {
@@ -429,14 +433,14 @@ void* doFetchRow(SRequestObj* pRequest) {
   if (pResultInfo->pData == NULL || pResultInfo->current >= pResultInfo->numOfRows) {
     pRequest->type = TSDB_MSG_TYPE_SHOW_RETRIEVE;
 
-    SRequestMsgBody body = buildRequestMsgImpl(pRequest);
+    SMsgSendInfo* body = buildSendMsgInfoImpl(pRequest);
 
-    int64_t transporterId = 0;
-    STscObj* pTscObj = pRequest->pTscObj;
-    sendMsgToServer(pTscObj->pTransporter, &pTscObj->pAppInfo->mgmtEp.epSet, &body, &transporterId);
+    int64_t  transporterId = 0;
+    STscObj *pTscObj = pRequest->pTscObj;
+    sendMsgToServer(pTscObj->pTransporter, &pTscObj->pAppInfo->mgmtEp.epSet, &transporterId, body);
 
     tsem_wait(&pRequest->body.rspSem);
-    destroyRequestMsgBody(&body);
+    destroySendMsgInfo(body);
 
     pResultInfo->current = 0;
     if (pResultInfo->numOfRows <= pResultInfo->current) {
diff --git a/source/client/src/clientMain.c b/source/client/src/clientMain.c
index f50765d37a82a2836cd671286d9bd64cdfc4f837..44c78076d9b3bd8e452039042af702adceba6930 100644
--- a/source/client/src/clientMain.c
+++ b/source/client/src/clientMain.c
@@ -35,14 +35,14 @@ void taos_cleanup(void) {
     return;
   }
 
-  int32_t id = tscReqRef;
-  tscReqRef = -1;
+  int32_t id = msgObjRefPool;
+  msgObjRefPool = -1;
   taosCloseRef(id);
 
   cleanupTaskQueue();
 
-  id = tscConnRef;
-  tscConnRef = -1;
+  id = clientConnRefPool;
+  clientConnRefPool = -1;
   taosCloseRef(id);
 
   rpcCleanup();
@@ -72,7 +72,7 @@ void taos_close(TAOS* taos) {
   STscObj *pTscObj = (STscObj *)taos;
   tscDebug("0x%"PRIx64" try to close connection, numOfReq:%d", pTscObj->id, pTscObj->numOfReqs);
 
-  taosRemoveRef(tscConnRef, pTscObj->id);
+  taosRemoveRef(clientConnRefPool, pTscObj->id);
 }
 
 int taos_errno(TAOS_RES *tres) {
@@ -130,7 +130,7 @@ TAOS_RES *taos_query(TAOS *taos, const char *sql) {
     return NULL;
   }
 
-  return taos_query_l(taos, sql, strlen(sql));
+  return taos_query_l(taos, sql, (int32_t) strlen(sql));
 }
 
 TAOS_ROW taos_fetch_row(TAOS_RES *pRes) {
@@ -140,7 +140,7 @@ TAOS_ROW taos_fetch_row(TAOS_RES *pRes) {
 
   SRequestObj *pRequest = (SRequestObj *) pRes;
   if (pRequest->type == TSDB_SQL_RETRIEVE_EMPTY_RESULT ||
-      pRequest->type == TSDB_SQL_INSERT) {
+      pRequest->type == TSDB_SQL_INSERT || pRequest->code != TSDB_CODE_SUCCESS) {
     return NULL;
   }
 
diff --git a/source/client/src/clientMsgHandler.c b/source/client/src/clientMsgHandler.c
index 548ea3d725f3cb43fafc393d69fad3d48ca73a87..b18b3ecb51483777072dcbbe7d36e20b3c2b880b 100644
--- a/source/client/src/clientMsgHandler.c
+++ b/source/client/src/clientMsgHandler.c
@@ -18,45 +18,23 @@
 #include "tname.h"
 #include "clientInt.h"
 #include "clientLog.h"
-#include "tmsgtype.h"
 #include "trpc.h"
 
-int (*handleRequestRspFp[TSDB_MSG_TYPE_MAX])(SRequestObj *pRequest, const char* pMsg, int32_t msgLen);
+int (*handleRequestRspFp[TSDB_MSG_TYPE_MAX])(void*, const SDataBuf* pMsg, int32_t code);
 
-int32_t buildConnectMsg(SRequestObj *pRequest, SRequestMsgBody* pMsgBody) {
-  pMsgBody->msgType         = TSDB_MSG_TYPE_CONNECT;
-  pMsgBody->msgInfo.len     = sizeof(SConnectMsg);
-  pMsgBody->requestObjRefId = pRequest->self;
-
-  SConnectMsg *pConnect = calloc(1, sizeof(SConnectMsg));
-  if (pConnect == NULL) {
-    terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
-    return -1;
-  }
-
-  // TODO refactor full_name
-  char *db;  // ugly code to move the space
-
-  STscObj *pObj = pRequest->pTscObj;
-  pthread_mutex_lock(&pObj->mutex);
-  db = strstr(pObj->db, TS_PATH_DELIMITER);
-
-  db = (db == NULL) ? pObj->db : db + 1;
-  tstrncpy(pConnect->db, db, sizeof(pConnect->db));
-  pthread_mutex_unlock(&pObj->mutex);
-
-  pConnect->pid = htonl(appInfo.pid);
-  pConnect->startTime = htobe64(appInfo.startTime);
-  tstrncpy(pConnect->app, appInfo.appName, tListLen(pConnect->app));
-
-  pMsgBody->msgInfo.pMsg = pConnect;
+int genericExecCallback(void* param, const SDataBuf* pMsg, int32_t code) {
+  SRequestObj* pRequest = param;
+  pRequest->code = code;
+  sem_post(&pRequest->body.rspSem);
   return 0;
 }
 
-int processConnectRsp(SRequestObj *pRequest, const char* pMsg, int32_t msgLen) {
+int processConnectRsp(void* param, const SDataBuf* pMsg, int32_t code) {
+  SRequestObj* pRequest = param;
+
   STscObj *pTscObj = pRequest->pTscObj;
 
-  SConnectRsp *pConnect = (SConnectRsp *)pMsg;
+  SConnectRsp *pConnect = (SConnectRsp *)pMsg->pData;
   pConnect->acctId    = htonl(pConnect->acctId);
   pConnect->connId    = htonl(pConnect->connId);
   pConnect->clusterId = htonl(pConnect->clusterId);
@@ -81,15 +59,19 @@ int processConnectRsp(SRequestObj *pRequest, const char* pMsg, int32_t msgLen) {
   pTscObj->pAppInfo->clusterId = pConnect->clusterId;
   atomic_add_fetch_64(&pTscObj->pAppInfo->numOfConns, 1);
 
-  pRequest->body.resInfo.pRspMsg = pMsg;
+//  pRequest->body.resInfo.pRspMsg = pMsg->pData;
   tscDebug("0x%" PRIx64 " clusterId:%d, totalConn:%"PRId64, pRequest->requestId, pConnect->clusterId, pTscObj->pAppInfo->numOfConns);
+
+  sem_post(&pRequest->body.rspSem);
   return 0;
 }
 
-static int32_t buildRetrieveMnodeMsg(SRequestObj *pRequest, SRequestMsgBody* pMsgBody) {
-  pMsgBody->msgType = TSDB_MSG_TYPE_SHOW_RETRIEVE;
-  pMsgBody->msgInfo.len = sizeof(SRetrieveTableMsg);
-  pMsgBody->requestObjRefId = pRequest->self;
+static int32_t buildRetrieveMnodeMsg(SRequestObj *pRequest, SMsgSendInfo* pMsgSendInfo) {
+  pMsgSendInfo->msgType         = TSDB_MSG_TYPE_SHOW_RETRIEVE;
+  pMsgSendInfo->msgInfo.len     = sizeof(SRetrieveTableMsg);
+  pMsgSendInfo->requestObjRefId = pRequest->self;
+  pMsgSendInfo->param           = pRequest;
+  pMsgSendInfo->fp              = handleRequestRspFp[pMsgSendInfo->msgType];
 
   SRetrieveTableMsg *pRetrieveMsg = calloc(1, sizeof(SRetrieveTableMsg));
   if (pRetrieveMsg == NULL) {
@@ -97,29 +79,38 @@ static int32_t buildRetrieveMnodeMsg(SRequestObj *pRequest, SRequestMsgBody* pMs
   }
 
   pRetrieveMsg->showId  = htonl(pRequest->body.execId);
-  pMsgBody->msgInfo.pMsg = pRetrieveMsg;
+  pMsgSendInfo->msgInfo.pData = pRetrieveMsg;
   return TSDB_CODE_SUCCESS;
 }
 
-SRequestMsgBody buildRequestMsgImpl(SRequestObj *pRequest) {
+SMsgSendInfo* buildSendMsgInfoImpl(SRequestObj *pRequest) {
+  SMsgSendInfo* pMsgSendInfo = calloc(1, sizeof(SMsgSendInfo));
+
   if (pRequest->type == TSDB_MSG_TYPE_SHOW_RETRIEVE) {
-    SRequestMsgBody body = {0};
-    buildRetrieveMnodeMsg(pRequest, &body);
-    return body;
+    buildRetrieveMnodeMsg(pRequest, pMsgSendInfo);
   } else {
     assert(pRequest != NULL);
-    SRequestMsgBody body = {
-        .requestObjRefId = pRequest->self,
-        .msgInfo         = pRequest->body.requestMsg,
-        .msgType         = pRequest->type,
-        .requestId       = pRequest->requestId,
-    };
-    return body;
+    pMsgSendInfo->requestObjRefId = pRequest->self;
+    pMsgSendInfo->msgInfo = pRequest->body.requestMsg;
+    pMsgSendInfo->msgType = pRequest->type;
+    pMsgSendInfo->requestId = pRequest->requestId;
+    pMsgSendInfo->param = pRequest;
+
+    pMsgSendInfo->fp = (handleRequestRspFp[pRequest->type] == NULL)? genericExecCallback:handleRequestRspFp[pRequest->type];
   }
+
+  return pMsgSendInfo;
 }
 
-int32_t processShowRsp(SRequestObj *pRequest, const char* pMsg, int32_t msgLen) {
-  SShowRsp* pShow = (SShowRsp *)pMsg;
+int32_t processShowRsp(void* param, const SDataBuf* pMsg, int32_t code) {
+  SRequestObj* pRequest = param;
+  if (code != TSDB_CODE_SUCCESS) {
+    pRequest->code = code;
+    tsem_post(&pRequest->body.rspSem);
+    return code;
+  }
+
+  SShowRsp* pShow = (SShowRsp *)pMsg->pData;
   pShow->showId   = htonl(pShow->showId);
 
   STableMetaMsg *pMetaMsg = &(pShow->tableMeta);
@@ -140,7 +131,7 @@ int32_t processShowRsp(SRequestObj *pRequest, const char* pMsg, int32_t msgLen)
     pFields[i].bytes = pSchema[i].bytes;
   }
 
-  pRequest->body.resInfo.pRspMsg = pMsg;
+//  pRequest->body.resInfo.pRspMsg = pMsg->pData;
   SReqResultInfo* pResInfo = &pRequest->body.resInfo;
 
   pResInfo->fields    = pFields;
@@ -150,16 +141,18 @@ int32_t processShowRsp(SRequestObj *pRequest, const char* pMsg, int32_t msgLen)
   pResInfo->length    = calloc(pResInfo->numOfCols, sizeof(int32_t));
 
   pRequest->body.execId = pShow->showId;
+  tsem_post(&pRequest->body.rspSem);
   return 0;
 }
 
-int32_t processRetrieveMnodeRsp(SRequestObj *pRequest, const char* pMsg, int32_t msgLen) {
-  assert(msgLen >= sizeof(SRetrieveTableRsp));
+int32_t processRetrieveMnodeRsp(void* param, const SDataBuf* pMsg, int32_t code) {
+  assert(pMsg->len >= sizeof(SRetrieveTableRsp));
 
-  tfree(pRequest->body.resInfo.pRspMsg);
-  pRequest->body.resInfo.pRspMsg = pMsg;
+  SRequestObj* pRequest = param;
+//  tfree(pRequest->body.resInfo.pRspMsg);
+//  pRequest->body.resInfo.pRspMsg = pMsg->pData;
 
-  SRetrieveTableRsp *pRetrieve = (SRetrieveTableRsp *) pMsg;
+  SRetrieveTableRsp *pRetrieve = (SRetrieveTableRsp *) pMsg->pData;
   pRetrieve->numOfRows  = htonl(pRetrieve->numOfRows);
   pRetrieve->precision  = htons(pRetrieve->precision);
 
@@ -172,29 +165,42 @@ int32_t processRetrieveMnodeRsp(SRequestObj *pRequest, const char* pMsg, int32_t
 
   tscDebug("0x%"PRIx64" numOfRows:%d, complete:%d, qId:0x%"PRIx64, pRequest->self, pRetrieve->numOfRows,
            pRetrieve->completed, pRequest->body.execId);
+
+  tsem_post(&pRequest->body.rspSem);
   return 0;
 }
 
-int32_t processCreateDbRsp(SRequestObj *pRequest, const char* pMsg, int32_t msgLen) {
+int32_t processCreateDbRsp(void* param, const SDataBuf* pMsg, int32_t code) {
   // todo rsp with the vnode id list
+  SRequestObj* pRequest = param;
+  tsem_post(&pRequest->body.rspSem);
 }
 
-int32_t processUseDbRsp(SRequestObj *pRequest, const char* pMsg, int32_t msgLen) {
-  SUseDbRsp* pUseDbRsp = (SUseDbRsp*) pMsg;
+int32_t processUseDbRsp(void* param, const SDataBuf* pMsg, int32_t code) {
+  SUseDbRsp* pUseDbRsp = (SUseDbRsp*) pMsg->pData;
   SName name = {0};
   tNameFromString(&name, pUseDbRsp->db, T_NAME_ACCT|T_NAME_DB);
 
   char db[TSDB_DB_NAME_LEN] = {0};
   tNameGetDbName(&name, db);
+
+  SRequestObj* pRequest = param;
   setConnectionDB(pRequest->pTscObj, db);
+
+  tsem_post(&pRequest->body.rspSem);
+  return 0;
 }
 
-int32_t processCreateTableRsp(SRequestObj *pRequest, const char* pMsg, int32_t msgLen) {
+int32_t processCreateTableRsp(void* param, const SDataBuf* pMsg, int32_t code) {
   assert(pMsg != NULL);
+  SRequestObj* pRequest = param;
+  tsem_post(&pRequest->body.rspSem);
 }
 
-int32_t processDropDbRsp(SRequestObj *pRequest, const char* pMsg, int32_t msgLen) {
+int32_t processDropDbRsp(void* param, const SDataBuf* pMsg, int32_t code) {
   // todo: Remove cache in catalog cache.
+  SRequestObj* pRequest = param;
+  tsem_post(&pRequest->body.rspSem);
 }
 
 void initMsgHandleFp() {
diff --git a/source/client/test/clientTests.cpp b/source/client/test/clientTests.cpp
index 2938d0180a958af8ace229e009e1b682e895abe4..1a5872f77a6eb6af5d7af2c97caad74a99aaa670 100644
--- a/source/client/test/clientTests.cpp
+++ b/source/client/test/clientTests.cpp
@@ -49,55 +49,55 @@ int main(int argc, char** argv) {
 
 TEST(testCase, driverInit_Test) { taos_init(); }
 
- TEST(testCase, connect_Test) {
-  TAOS* pConn = taos_connect("ubuntu", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-  taos_close(pConn);
-}
-
- TEST(testCase, create_user_Test) {
+TEST(testCase, connect_Test) {
   TAOS* pConn = taos_connect("ubuntu", "root", "taosdata", NULL, 0);
   assert(pConn != NULL);
-
-  TAOS_RES* pRes = taos_query(pConn, "create user abc pass 'abc'");
-  if (taos_errno(pRes) != TSDB_CODE_SUCCESS) {
-    printf("failed to create user, reason:%s\n", taos_errstr(pRes));
-  }
-
-  taos_free_result(pRes);
   taos_close(pConn);
 }
 
- TEST(testCase, create_account_Test) {
-  TAOS* pConn = taos_connect("ubuntu", "root", "taosdata", NULL, 0);
-  assert(pConn != NULL);
-
-  TAOS_RES* pRes = taos_query(pConn, "create account aabc pass 'abc'");
-  if (taos_errno(pRes) != TSDB_CODE_SUCCESS) {
-    printf("failed to create user, reason:%s\n", taos_errstr(pRes));
-  }
-
-  taos_free_result(pRes);
-  taos_close(pConn);
-}
+//TEST(testCase, create_user_Test) {
+//  TAOS* pConn = taos_connect("ubuntu", "root", "taosdata", NULL, 0);
+//  assert(pConn != NULL);
+//
+//  TAOS_RES* pRes = taos_query(pConn, "create user abc pass 'abc'");
+//  if (taos_errno(pRes) != TSDB_CODE_SUCCESS) {
+//    printf("failed to create user, reason:%s\n", taos_errstr(pRes));
+//  }
+//
+//  taos_free_result(pRes);
+//  taos_close(pConn);
+//}
+//
+//TEST(testCase, create_account_Test) {
+//  TAOS* pConn = taos_connect("ubuntu", "root", "taosdata", NULL, 0);
+//  assert(pConn != NULL);
+//
+//  TAOS_RES* pRes = taos_query(pConn, "create account aabc pass 'abc'");
+//  if (taos_errno(pRes) != TSDB_CODE_SUCCESS) {
+//    printf("failed to create user, reason:%s\n", taos_errstr(pRes));
+//  }
+//
+//  taos_free_result(pRes);
+//  taos_close(pConn);
+//}
+//
+//TEST(testCase, drop_account_Test) {
+//  TAOS* pConn = taos_connect("ubuntu", "root", "taosdata", NULL, 0);
+//  assert(pConn != NULL);
+//
+//  TAOS_RES* pRes = taos_query(pConn, "drop account aabc");
+//  if (taos_errno(pRes) != TSDB_CODE_SUCCESS) {
+//    printf("failed to create user, reason:%s\n", taos_errstr(pRes));
+//  }
+//
+//  taos_free_result(pRes);
+//  taos_close(pConn);
+//}
 
- TEST(testCase, drop_account_Test) {
+TEST(testCase, show_user_Test) {
   TAOS* pConn = taos_connect("ubuntu", "root", "taosdata", NULL, 0);
   assert(pConn != NULL);
 
-  TAOS_RES* pRes = taos_query(pConn, "drop account aabc");
-  if (taos_errno(pRes) != TSDB_CODE_SUCCESS) {
-    printf("failed to create user, reason:%s\n", taos_errstr(pRes));
-  }
-
-  taos_free_result(pRes);
-  taos_close(pConn);
-}
-
- TEST(testCase, show_user_Test) {
-  TAOS* pConn = taos_connect("ubuntu", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-
   TAOS_RES* pRes = taos_query(pConn, "show users");
   TAOS_ROW pRow = NULL;
 
@@ -113,7 +113,7 @@ TEST(testCase, driverInit_Test) { taos_init(); }
   taos_close(pConn);
 }
 
- TEST(testCase, drop_user_Test) {
+TEST(testCase, drop_user_Test) {
   TAOS* pConn = taos_connect("ubuntu", "root", "taosdata", NULL, 0);
   assert(pConn != NULL);
 
@@ -126,7 +126,7 @@ TEST(testCase, driverInit_Test) { taos_init(); }
   taos_close(pConn);
 }
 
- TEST(testCase, show_db_Test) {
+TEST(testCase, show_db_Test) {
   TAOS* pConn = taos_connect("ubuntu", "root", "taosdata", NULL, 0);
 //  assert(pConn != NULL);
 
@@ -191,10 +191,15 @@ TEST(testCase, drop_db_test) {
   if (taos_errno(pRes) != 0) {
     printf("failed to drop db, reason:%s\n", taos_errstr(pRes));
   }
-
   taos_free_result(pRes);
 
   showDB(pConn);
+
+  pRes = taos_query(pConn, "create database abc1");
+  if (taos_errno(pRes) != 0) {
+    printf("create to drop db, reason:%s\n", taos_errstr(pRes));
+  }
+  taos_free_result(pRes);
   taos_close(pConn);
 }
 
@@ -248,7 +253,19 @@ TEST(testCase, show_stable_Test) {
   TAOS* pConn = taos_connect("ubuntu", "root", "taosdata", NULL, 0);
   assert(pConn != NULL);
 
-  TAOS_RES* pRes = taos_query(pConn, "show stables");
+  TAOS_RES* pRes = taos_query(pConn, "use abc1");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to use db, reason:%s\n", taos_errstr(pRes));
+  }
+  taos_free_result(pRes);
+
+  pRes = taos_query(pConn, "show stables");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to show stables, reason:%s\n", taos_errstr(pRes));
+    taos_free_result(pRes);
+    ASSERT_TRUE(false);
+  }
+
   TAOS_ROW pRow = NULL;
 
   TAOS_FIELD* pFields = taos_fetch_fields(pRes);
diff --git a/source/libs/parser/inc/astToMsg.h b/source/libs/parser/inc/astToMsg.h
index c0c3c8386b5237707881204efd00dcda07896126..361b4e71cb0ca3834f78990aaffbef26d27d4bfe 100644
--- a/source/libs/parser/inc/astToMsg.h
+++ b/source/libs/parser/inc/astToMsg.h
@@ -7,7 +7,7 @@
 SCreateUserMsg* buildUserManipulationMsg(SSqlInfo* pInfo, int32_t* outputLen, int64_t id, char* msgBuf, int32_t msgLen);
 SCreateAcctMsg* buildAcctManipulationMsg(SSqlInfo* pInfo, int32_t* outputLen, int64_t id, char* msgBuf, int32_t msgLen);
 SDropUserMsg* buildDropUserMsg(SSqlInfo* pInfo, int32_t* outputLen, int64_t id, char* msgBuf, int32_t msgLen);
-SShowMsg* buildShowMsg(SShowInfo* pShowInfo, int64_t id, char* msgBuf, int32_t msgLen);
+SShowMsg* buildShowMsg(SShowInfo* pShowInfo, SParseBasicCtx* pParseCtx, char* msgBuf, int32_t msgLen);
 SCreateDbMsg* buildCreateDbMsg(SCreateDbInfo* pCreateDbInfo, SParseBasicCtx *pCtx, SMsgBuf* pMsgBuf);
 SCreateStbMsg* buildCreateTableMsg(SCreateTableSql* pCreateTableSql, int32_t* len, SParseBasicCtx* pParseCtx, SMsgBuf* pMsgBuf);
 SDropTableMsg* buildDropTableMsg(SSqlInfo* pInfo, int32_t* len, SParseBasicCtx* pParseCtx, SMsgBuf* pMsgBuf);
diff --git a/source/libs/parser/src/astToMsg.c b/source/libs/parser/src/astToMsg.c
index 00f3d3f7162cb4df8de51d7755fce8911dbfaa57..7f2f15ac650845c5d15d2492bcd61e425caf2715 100644
--- a/source/libs/parser/src/astToMsg.c
+++ b/source/libs/parser/src/astToMsg.c
@@ -86,7 +86,7 @@ SDropUserMsg* buildDropUserMsg(SSqlInfo* pInfo, int32_t *msgLen, int64_t id, cha
   return pMsg;
 }
 
-SShowMsg* buildShowMsg(SShowInfo* pShowInfo, int64_t id, char* msgBuf, int32_t msgLen) {
+SShowMsg* buildShowMsg(SShowInfo* pShowInfo, SParseBasicCtx *pCtx, char* msgBuf, int32_t msgLen) {
   SShowMsg* pShowMsg = calloc(1, sizeof(SShowMsg));
 
   pShowMsg->type = pShowInfo->showType;
@@ -105,6 +105,12 @@ SShowMsg* buildShowMsg(SShowInfo* pShowInfo, int64_t id, char* msgBuf, int32_t m
     pShowMsg->payloadLen = htons(pEpAddr->n);
   }
 
+  if (pShowInfo->showType == TSDB_MGMT_TABLE_STB || pShowInfo->showType == TSDB_MGMT_TABLE_VGROUP) {
+    SName n = {0};
+    tNameSetDbName(&n, pCtx->acctId, pCtx->db, strlen(pCtx->db));
+    tNameGetFullDbName(&n, pShowMsg->db);
+  }
+
   return pShowMsg;
 }
 
diff --git a/source/libs/parser/src/astValidate.c b/source/libs/parser/src/astValidate.c
index cd11607326a33a8b277dbed0367138e269865b86..2510f354fb3e8fda29012ed1ca26a0647e3bbb80 100644
--- a/source/libs/parser/src/astValidate.c
+++ b/source/libs/parser/src/astValidate.c
@@ -4090,7 +4090,7 @@ static int32_t setShowInfo(SShowInfo* pShowInfo, SParseBasicCtx *pCtx, void** ou
     }
   }
 
-  *output = buildShowMsg(pShowInfo, pCtx->requestId, pMsgBuf->buf, pMsgBuf->len);
+  *output = buildShowMsg(pShowInfo, pCtx, pMsgBuf->buf, pMsgBuf->len);
   *outputLen = sizeof(SShowMsg)/* + htons(pShowMsg->payloadLen)*/;
   return TSDB_CODE_SUCCESS;
 }