fix bug

src/client/src/tscSub.c

@@ -509,6 +509,7 @@ TAOS_RES *taos_consume(TAOS_SUB *tsub) {
     }
     pSub->pSql = pSql;
     pSql->pSubscription = pSub;
+    pSub->lastSyncTime = 0;
 
     // no table list now, force to update it
     tscDebug("begin table synchronization");