[td-430] fix bug while client does not retrieve or paritally retrieve result from vnode.

src/client/src/tscServer.c

@@ -217,10 +217,12 @@ void tscProcessMsgFromServer(SRpcMsg *rpcMsg, SRpcIpSet *pIpSet) {
   STscObj *pObj = pSql->pTscObj;
   // tscTrace("%p msg:%s is received from server", pSql, taosMsg[rpcMsg->msgType]);
 
-  if (pSql->freed || pObj->signature != pObj) {
+  if (pObj->signature != pObj) {
     tscTrace("%p sql is already released or DB connection is closed, freed:%d pObj:%p signature:%p", pSql, pSql->freed,
              pObj, pObj->signature);
+    if (pSql != pObj->pSql) {
       tscFreeSqlObj(pSql);
+    }
     rpcFreeCont(rpcMsg->pCont);
     return;
   }
@@ -1867,8 +1869,8 @@ int tscProcessTableMetaRsp(SSqlObj *pSql) {
     return TSDB_CODE_CLI_OUT_OF_MEMORY;
   }
 
-  free(pTableMeta);
   tscTrace("%p recv table meta: %"PRId64 ", tid:%d, name:%s", pSql, pTableMeta->uid, pTableMeta->sid, pTableMetaInfo->name);
+  free(pTableMeta);
   
   return TSDB_CODE_SUCCESS;
 }

src/client/src/tscSql.c

@@ -576,26 +576,22 @@ void taos_free_result_imp(TAOS_RES *res, int keepCmd) {
    *         for each subquery. Because the failure of execution tsProcessSql may trigger the callback function
    *         be executed, and the retry efforts may result in double free the resources, e.g.,SRetrieveSupport
    */
-  if ((pCmd->command == TSDB_SQL_SELECT || pCmd->command == TSDB_SQL_SHOW || pCmd->command == TSDB_SQL_RETRIEVE ||
+  if ((pCmd->command == TSDB_SQL_SELECT ||
+       pCmd->command == TSDB_SQL_SHOW ||
+       pCmd->command == TSDB_SQL_RETRIEVE ||
        pCmd->command == TSDB_SQL_FETCH) &&
-      (pRes->code != TSDB_CODE_QUERY_CANCELLED && ((pRes->numOfRows > 0 && pCmd->command < TSDB_SQL_LOCAL && pRes->completed == false) ||
-       (pRes->code == TSDB_CODE_SUCCESS && pRes->numOfRows == 0 && pCmd->command == TSDB_SQL_SELECT &&
-        pSql->pStream == NULL && pTableMetaInfo->pTableMeta != NULL)))) {
+       (pRes->code != TSDB_CODE_QUERY_CANCELLED && ((pCmd->command < TSDB_SQL_LOCAL && pRes->completed == false) ||
+       (pRes->code == TSDB_CODE_SUCCESS && pCmd->command == TSDB_SQL_SELECT && pSql->pStream == NULL && pTableMetaInfo->pTableMeta != NULL)))) {
     pCmd->command = (pCmd->command > TSDB_SQL_MGMT) ? TSDB_SQL_RETRIEVE : TSDB_SQL_FETCH;
 
-    tscTrace("%p code:%d, numOfRows:%d, command:%d", pSql, pRes->code, pRes->numOfRows, pCmd->command);
+    tscTrace("%p send msg to free qhandle in vnode, code:%d, numOfRows:%d, command:%s", pSql, pRes->code, pRes->numOfRows,
+        sqlCmd[pCmd->command]);
 
     pSql->freed = 1;
     tscProcessSql(pSql);
   
-    /*
-     *  If release connection msg is sent to vnode, the corresponding SqlObj for async query can not be freed instantly,
-     *  since its free operation is delegated to callback function, which is tscProcessMsgFromServer.
-     */
-    STscObj* pObj = pSql->pTscObj;
-    if (pObj->pSql == pSql) {
-      pObj->pSql = NULL;
-    }
+    // waits for response and then goes on
+    sem_wait(&pSql->rspSem);
   } else { // if no free resource msg is sent to vnode, we free this object immediately.
     STscObj* pTscObj = pSql->pTscObj;
     

src/client/src/tscUtil.c

@@ -423,6 +423,8 @@ void tscFreeSqlObj(SSqlObj* pSql) {
   tfree(pCmd->payload);
 
   pCmd->allocSize = 0;
+  
+  tfree(pSql->sqlstr);
   free(pSql);
 }