diff --git a/src/client/inc/tsclient.h b/src/client/inc/tsclient.h
index fd82cbb8c5..054b2894c5 100644
--- a/src/client/inc/tsclient.h
+++ b/src/client/inc/tsclient.h
@@ -408,7 +408,7 @@ int  tscProcessSql(SSqlObj *pSql);
 int  tscRenewMeterMeta(SSqlObj *pSql, char *tableId);
 void tscQueueAsyncRes(SSqlObj *pSql);
 
-void tscQueueAsyncError(void(*fp), void *param);
+void tscQueueAsyncError(void(*fp), void *param, int32_t code);
 
 int tscProcessLocalCmd(SSqlObj *pSql);
 int tscCfgDynamicOptions(char *msg);
@@ -449,7 +449,7 @@ void tscFreeSqlObj(SSqlObj *pObj);
 
 void tscCloseTscObj(STscObj *pObj);
 
-void doAsyncQuery(STscObj* pObj, SSqlObj* pSql, void (*fp)(), void* param, const char* sqlstr, int32_t sqlLen);
+void doAsyncQuery(STscObj* pObj, SSqlObj* pSql, void (*fp)(), void* param, const char* sqlstr, size_t sqlLen);
 
 void tscProcessMultiVnodesInsert(SSqlObj *pSql);
 void tscProcessMultiVnodesInsertFromFile(SSqlObj *pSql);
diff --git a/src/client/src/tscAsync.c b/src/client/src/tscAsync.c
index f05d269925..10878ee37f 100644
--- a/src/client/src/tscAsync.c
+++ b/src/client/src/tscAsync.c
@@ -40,7 +40,7 @@ static void tscProcessAsyncRetrieveImpl(void *param, TAOS_RES *tres, int numOfRo
 static void tscAsyncFetchRowsProxy(void *param, TAOS_RES *tres, int numOfRows);
 static void tscAsyncFetchSingleRowProxy(void *param, TAOS_RES *tres, int numOfRows);
 
-void doAsyncQuery(STscObj* pObj, SSqlObj* pSql, void (*fp)(), void* param, const char* sqlstr, int32_t sqlLen) {
+void doAsyncQuery(STscObj* pObj, SSqlObj* pSql, void (*fp)(), void* param, const char* sqlstr, size_t sqlLen) {
   SSqlCmd *pCmd = &pSql->cmd;
   SSqlRes *pRes = &pSql->res;
   
@@ -51,14 +51,14 @@ void doAsyncQuery(STscObj* pObj, SSqlObj* pSql, void (*fp)(), void* param, const
   
   if (TSDB_CODE_SUCCESS != tscAllocPayload(pCmd, TSDB_DEFAULT_PAYLOAD_SIZE)) {
     tscError("failed to malloc payload");
-    tscQueueAsyncError(fp, param);
+    tscQueueAsyncError(fp, param, TSDB_CODE_CLI_OUT_OF_MEMORY);
     return;
   }
   
   pSql->sqlstr = realloc(pSql->sqlstr, sqlLen + 1);
   if (pSql->sqlstr == NULL) {
     tscError("%p failed to malloc sql string buffer", pSql);
-    tscQueueAsyncError(fp, param);
+    tscQueueAsyncError(fp, param, TSDB_CODE_CLI_OUT_OF_MEMORY);
     free(pCmd->payload);
     return;
   }
@@ -73,7 +73,7 @@ void doAsyncQuery(STscObj* pObj, SSqlObj* pSql, void (*fp)(), void* param, const
   if (code == TSDB_CODE_ACTION_IN_PROGRESS) return;
   
   if (code != TSDB_CODE_SUCCESS) {
-    pSql->res.code = (uint8_t)code;
+    pSql->res.code = code;
     tscQueueAsyncRes(pSql);
     return;
   }
@@ -86,15 +86,16 @@ void taos_query_a(TAOS *taos, const char *sqlstr, __async_cb_func_t fp, void *pa
   STscObj *pObj = (STscObj *)taos;
   if (pObj == NULL || pObj->signature != pObj) {
     tscError("bug!!! pObj:%p", pObj);
-    globalCode = TSDB_CODE_DISCONNECTED;
-    tscQueueAsyncError(fp, param);
+    terrno = TSDB_CODE_DISCONNECTED;
+    tscQueueAsyncError(fp, param, TSDB_CODE_DISCONNECTED);
     return;
   }
   
   int32_t sqlLen = strlen(sqlstr);
   if (sqlLen > tsMaxSQLStringLen) {
     tscError("sql string too long");
-    tscQueueAsyncError(fp, param);
+    terrno = TSDB_CODE_INVALID_SQL;
+    tscQueueAsyncError(fp, param, TSDB_CODE_INVALID_SQL);
     return;
   }
   
@@ -103,7 +104,8 @@ void taos_query_a(TAOS *taos, const char *sqlstr, __async_cb_func_t fp, void *pa
   SSqlObj *pSql = (SSqlObj *)calloc(1, sizeof(SSqlObj));
   if (pSql == NULL) {
     tscError("failed to malloc sqlObj");
-    tscQueueAsyncError(fp, param);
+    terrno = TSDB_CODE_CLI_OUT_OF_MEMORY;
+    tscQueueAsyncError(fp, param, TSDB_CODE_CLI_OUT_OF_MEMORY);
     return;
   }
   
@@ -168,7 +170,7 @@ static void tscProcessAsyncRetrieveImpl(void *param, TAOS_RES *tres, int numOfRo
       pRes->code = numOfRows;
     }
 
-    tscQueueAsyncError(pSql->fetchFp, param);
+    tscQueueAsyncError(pSql->fetchFp, param, pRes->code);
     return;
   }
 
@@ -198,8 +200,8 @@ void taos_fetch_rows_a(TAOS_RES *taosa, void (*fp)(void *, TAOS_RES *, int), voi
   SSqlObj *pSql = (SSqlObj *)taosa;
   if (pSql == NULL || pSql->signature != pSql) {
     tscError("sql object is NULL");
-    globalCode = TSDB_CODE_DISCONNECTED;
-    tscQueueAsyncError(fp, param);
+//    globalCode = TSDB_CODE_DISCONNECTED;
+    tscQueueAsyncError(fp, param, TSDB_CODE_DISCONNECTED);
     return;
   }
 
@@ -208,7 +210,7 @@ void taos_fetch_rows_a(TAOS_RES *taosa, void (*fp)(void *, TAOS_RES *, int), voi
 
   if (pRes->qhandle == 0) {
     tscError("qhandle is NULL");
-    tscQueueAsyncError(fp, param);
+    tscQueueAsyncError(fp, param, TSDB_CODE_INVALID_QHANDLE);
     return;
   }
 
@@ -230,8 +232,8 @@ void taos_fetch_row_a(TAOS_RES *taosa, void (*fp)(void *, TAOS_RES *, TAOS_ROW),
   SSqlObj *pSql = (SSqlObj *)taosa;
   if (pSql == NULL || pSql->signature != pSql) {
     tscError("sql object is NULL");
-    globalCode = TSDB_CODE_DISCONNECTED;
-    tscQueueAsyncError(fp, param);
+//    globalCode = TSDB_CODE_DISCONNECTED;
+    tscQueueAsyncError(fp, param, TSDB_CODE_DISCONNECTED);
     return;
   }
 
@@ -240,7 +242,7 @@ void taos_fetch_row_a(TAOS_RES *taosa, void (*fp)(void *, TAOS_RES *, TAOS_ROW),
 
   if (pRes->qhandle == 0) {
     tscError("qhandle is NULL");
-    tscQueueAsyncError(fp, param);
+    tscQueueAsyncError(fp, param, TSDB_CODE_INVALID_QHANDLE);
     return;
   }
 
@@ -329,7 +331,7 @@ void tscProcessAsyncRes(SSchedMsg *pMsg) {
 
   // pCmd may be released, so cache pCmd->command
   int cmd = pCmd->command;
-  int code = pRes->code ? -pRes->code : pRes->numOfRows;
+  int code = pRes->code;// ? -pRes->code : pRes->numOfRows;
 
   // in case of async insert, restore the user specified callback function
   bool shouldFree = tscShouldFreeAsyncSqlObj(pSql);
@@ -347,18 +349,20 @@ void tscProcessAsyncRes(SSchedMsg *pMsg) {
   }
 }
 
-void tscProcessAsyncError(SSchedMsg *pMsg) {
+static void tscProcessAsyncError(SSchedMsg *pMsg) {
   void (*fp)() = pMsg->ahandle;
-
-  (*fp)(pMsg->thandle, NULL, -1);
+  (*fp)(pMsg->thandle, NULL, *(int32_t*)pMsg->msg);
 }
 
-void tscQueueAsyncError(void(*fp), void *param) {
+void tscQueueAsyncError(void(*fp), void *param, int32_t code) {
+  int32_t* c = malloc(sizeof(int32_t));
+  *c = code;
+  
   SSchedMsg schedMsg;
   schedMsg.fp = tscProcessAsyncError;
   schedMsg.ahandle = fp;
   schedMsg.thandle = param;
-  schedMsg.msg = NULL;
+  schedMsg.msg = c;
   taosScheduleTask(tscQhandle, &schedMsg);
 }
 
diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index 591b41d948..f651c35324 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -329,7 +329,7 @@ void tscProcessMsgFromServer(SRpcMsg *rpcMsg) {
     void *taosres = tscKeepConn[pCmd->command] ? pSql : NULL;
     rpcMsg->code = pRes->code ? pRes->code : pRes->numOfRows;
     
-    tscTrace("%p Async SQL result:%s res:%p", pSql, tstrerror(pRes->code), taosres);
+    tscTrace("%p Async SQL result:%s res:%p", pSql, tstrerror(pRes->code), pSql);
 
     /*
      * Whether to free sqlObj or not should be decided before call the user defined function, since this SqlObj
diff --git a/src/client/src/tscSql.c b/src/client/src/tscSql.c
index 0fe281859b..896f7e294f 100644
--- a/src/client/src/tscSql.c
+++ b/src/client/src/tscSql.c
@@ -267,25 +267,25 @@ int taos_query_imp(STscObj *pObj, SSqlObj *pSql) {
   return pRes->code;
 }
 
-static void syncQueryCallback(void *param, TAOS_RES *tres, int code) {
+static void waitForQueryRsp(void *param, TAOS_RES *tres, int code) {
   assert(param != NULL);
-  STscObj *pObj = (STscObj *)param;
+  SSqlObj *pSql = ((STscObj *)param)->pSql;
   
-  assert(pObj->pSql != NULL);
-  sem_post(&pObj->pSql->rspSem);
+  pSql->res.code = code;
+  sem_post(&pSql->rspSem);
 }
 
 int taos_query(TAOS *taos, const char *sqlstr) {
   STscObj *pObj = (STscObj *)taos;
   if (pObj == NULL || pObj->signature != pObj) {
-    globalCode = TSDB_CODE_DISCONNECTED;
+    terrno = TSDB_CODE_DISCONNECTED;
     return TSDB_CODE_DISCONNECTED;
   }
   
   SSqlObj* pSql = pObj->pSql;
   
-  int32_t sqlLen = strlen(sqlstr);
-  doAsyncQuery(pObj, pObj->pSql, syncQueryCallback, taos, sqlstr, sqlLen);
+  size_t sqlLen = strlen(sqlstr);
+  doAsyncQuery(pObj, pObj->pSql, waitForQueryRsp, taos, sqlstr, sqlLen);
 
   // wait for the callback function to post the semaphore
   sem_wait(&pSql->rspSem);
@@ -643,7 +643,7 @@ static void **tscBuildResFromSubqueries(SSqlObj *pSql) {
   return pRes->tsrow;
 }
 
-static void asyncFetchCallback(void *param, TAOS_RES *tres, int numOfRows) {
+static void waitForRetrieveRsp(void *param, TAOS_RES *tres, int numOfRows) {
   SSqlObj* pSql = (SSqlObj*) tres;
   
   if (numOfRows < 0) { // set the error code
@@ -671,7 +671,7 @@ TAOS_ROW taos_fetch_row(TAOS_RES *res) {
   // current data are exhausted, fetch more data
   if (pRes->data == NULL || (pRes->data != NULL && pRes->row >= pRes->numOfRows && pRes->completed != true &&
       (pCmd->command == TSDB_SQL_RETRIEVE || pCmd->command == TSDB_SQL_RETRIEVE_METRIC || pCmd->command == TSDB_SQL_FETCH))) {
-    taos_fetch_rows_a(res, asyncFetchCallback, pSql->pTscObj);
+    taos_fetch_rows_a(res, waitForRetrieveRsp, pSql->pTscObj);
     
     sem_wait(&pSql->rspSem);
   }
@@ -848,22 +848,17 @@ void taos_free_result_imp(TAOS_RES *res, int keepCmd) {
 
 void taos_free_result(TAOS_RES *res) { taos_free_result_imp(res, 0); }
 
+// todo should not be used in async query
 int taos_errno(TAOS *taos) {
   STscObj *pObj = (STscObj *)taos;
-  int      code;
 
-  if (pObj == NULL || pObj->signature != pObj) return globalCode;
+  if (pObj == NULL || pObj->signature != pObj) {
+    return terrno;
+  }
 
-  if ((int8_t)(pObj->pSql->res.code) == -1)
-    code = TSDB_CODE_OTHERS;
-  else
-    code = pObj->pSql->res.code;
-
-  return code;
+  return pObj->pSql->res.code;
 }
 
-//static bool validErrorCode(int32_t code) { return code >= TSDB_CODE_SUCCESS && code < TSDB_CODE_MAX_ERROR_CODE; }
-
 /*
  * In case of invalid sql error, additional information is attached to explain
  * why the sql is invalid
@@ -883,6 +878,7 @@ static bool hasAdditionalErrorInfo(int32_t code, SSqlCmd *pCmd) {
   return z != NULL;
 }
 
+// todo should not be used in async model
 char *taos_errstr(TAOS *taos) {
   STscObj *pObj = (STscObj *)taos;
 
diff --git a/src/os/linux/src/tlinux.c b/src/os/linux/src/tlinux.c
index bce4a8f13d..780e2903a0 100644
--- a/src/os/linux/src/tlinux.c
+++ b/src/os/linux/src/tlinux.c
@@ -236,7 +236,7 @@ void *taosProcessAlarmSignal(void *tharg) {
   void (*callback)(int) = tharg;
 
   timer_t         timerId;
-  struct sigevent sevent;
+  struct sigevent sevent = {0};
 
   #ifdef _ALPINE
     sevent.sigev_notify = SIGEV_THREAD;