Merge pull request #4412 from taosdata/bugfix/td-2290

fix td-2290

src/client/src/tscSub.c

@@ -157,7 +157,7 @@ static SSub* tscCreateSubscription(STscObj* pObj, const char* topic, const char*
 
   registerSqlObj(pSql);
 
-  code = tsParseSql(pSql, false);
+  code = tsParseSql(pSql, true);
   if (code == TSDB_CODE_TSC_ACTION_IN_PROGRESS) {
     tsem_wait(&pSub->sem);
     code = pSql->res.code;
@@ -168,7 +168,7 @@ static SSub* tscCreateSubscription(STscObj* pObj, const char* topic, const char*
     goto fail;
   }
 
-  if (pSql->cmd.command != TSDB_SQL_SELECT) {
+  if (pSql->cmd.command != TSDB_SQL_SELECT && pSql->cmd.command != TSDB_SQL_RETRIEVE_EMPTY_RESULT) {
     line = __LINE__;
     code = TSDB_CODE_TSC_INVALID_SQL;
     goto fail;
@@ -182,7 +182,7 @@ fail:
     if (pSql->self != 0) {
       taosReleaseRef(tscObjRef, pSql->self);
     } else {
-      tscFreeSqlObj(pSql);
+    tscFreeSqlObj(pSql);
     }
 
     pSql = NULL;
@@ -401,9 +401,11 @@ TAOS_SUB *taos_subscribe(TAOS *taos, int restart, const char* topic, const char
     tscLoadSubscriptionProgress(pSub);
   }
 
-  if (!tscUpdateSubscription(pObj, pSub)) {
-    taos_unsubscribe(pSub, 1);
-    return NULL;
+  if (pSub->pSql->cmd.command == TSDB_SQL_SELECT) {
+    if (!tscUpdateSubscription(pObj, pSub)) {
+      taos_unsubscribe(pSub, 1);
+      return NULL;
+    }
   }
 
   pSub->interval = interval;
@@ -417,10 +419,80 @@ TAOS_SUB *taos_subscribe(TAOS *taos, int restart, const char* topic, const char
   return pSub;
 }
 
+SSqlObj* recreateSqlObj(SSub* pSub) {
+  SSqlObj* pSql = calloc(1, sizeof(SSqlObj));
+  if (pSql == NULL) {
+    return NULL;
+  }
+
+  pSql->signature = pSql;
+  pSql->pTscObj = pSub->taos;
+
+  SSqlCmd* pCmd = &pSql->cmd;
+  SSqlRes* pRes = &pSql->res;
+  if (tsem_init(&pSql->rspSem, 0, 0) == -1) {
+    tscFreeSqlObj(pSql);
+    return NULL;
+  }
+
+  pSql->param = pSub;
+  pSql->maxRetry = TSDB_MAX_REPLICA;
+  pSql->fp = asyncCallback;
+  pSql->fetchFp = asyncCallback;
+  pSql->sqlstr = strdup(pSub->pSql->sqlstr);
+  if (pSql->sqlstr == NULL) {
+    tscFreeSqlObj(pSql);
+    return NULL;
+  }
+
+  pRes->qhandle = 0;
+  pRes->numOfRows = 1;
+
+  int code = tscAllocPayload(pCmd, TSDB_DEFAULT_PAYLOAD_SIZE);
+  if (code != TSDB_CODE_SUCCESS) {
+    tscFreeSqlObj(pSql);
+    return NULL;
+  }
+
+  registerSqlObj(pSql);
+
+  code = tsParseSql(pSql, true);
+  if (code == TSDB_CODE_TSC_ACTION_IN_PROGRESS) {
+    tsem_wait(&pSub->sem);
+    code = pSql->res.code;
+  }
+
+  if (code != TSDB_CODE_SUCCESS) {
+    taosReleaseRef(tscObjRef, pSql->self);
+    return NULL;
+  }
+
+  if (pSql->cmd.command != TSDB_SQL_SELECT) {
+    taosReleaseRef(tscObjRef, pSql->self);
+    return NULL;
+  }
+
+  return pSql;
+}
+
 TAOS_RES *taos_consume(TAOS_SUB *tsub) {
   SSub *pSub = (SSub *)tsub;
   if (pSub == NULL) return NULL;
 
+  if (pSub->pSql->cmd.command == TSDB_SQL_RETRIEVE_EMPTY_RESULT) {
+    SSqlObj* pSql = recreateSqlObj(pSub);
+    if (pSql == NULL) {
+      return NULL;
+    }
+    if (pSub->pSql->self != 0) {
+      taosReleaseRef(tscObjRef, pSub->pSql->self);
+    } else {
+      tscFreeSqlObj(pSub->pSql);
+    }
+    pSub->pSql = pSql;
+    pSql->pSubscription = pSub;
+  }
+
   tscSaveSubscriptionProgress(pSub);
 
   SSqlObj *pSql = pSub->pSql;
@@ -512,10 +584,13 @@ void taos_unsubscribe(TAOS_SUB *tsub, int keepProgress) {
   }
 
   if (pSub->pSql != NULL) {
-    taos_free_result(pSub->pSql);
+    if (pSub->pSql->self != 0) {
+      taosReleaseRef(tscObjRef, pSub->pSql->self);
+    } else {
+      tscFreeSqlObj(pSub->pSql);
+    }
   }
 
-  tscFreeSqlObj(pSub->pSql);
   taosArrayDestroy(pSub->progress);
   tsem_destroy(&pSub->sem);
   memset(pSub, 0, sizeof(*pSub));