| // Licensed to the Apache Software Foundation (ASF) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The ASF licenses this file |
| // to you under the Apache License, Version 2.0 (the |
| // "License"); you may not use this file except in compliance |
| // with the License. You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, |
| // software distributed under the License is distributed on an |
| // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| // KIND, either express or implied. See the License for the |
| // specific language governing permissions and limitations |
| // under the License. |
| |
| package org.apache.impala.catalog.events; |
| |
| import java.util.Collections; |
| import java.util.List; |
| import org.apache.hadoop.hive.metastore.api.CurrentNotificationEventId; |
| import org.apache.hadoop.hive.metastore.api.NotificationEvent; |
| import org.apache.hadoop.hive.metastore.api.NotificationEventResponse; |
| import org.apache.impala.catalog.CatalogException; |
| import org.apache.impala.catalog.CatalogServiceCatalog; |
| import org.apache.impala.catalog.MetaStoreClientPool.MetaStoreClient; |
| import org.apache.thrift.TException; |
| |
| /** |
| * A test MetastoreEventProcessor which executes in the same thread. Useful for testing |
| * functionality of MetastoreEventsProcessor |
| */ |
| public class SynchronousHMSEventProcessorForTests extends MetastoreEventsProcessor { |
| SynchronousHMSEventProcessorForTests( |
| CatalogServiceCatalog catalog, long startSyncFromId, long pollingFrequencyInSec) |
| throws CatalogException { |
| super(catalog, startSyncFromId, pollingFrequencyInSec); |
| } |
| |
| @Override |
| public void startScheduler() { |
| // nothing to do here; there is no background thread for this processor |
| } |
| |
| public List<NotificationEvent> getNextNotificationEvents(long eventId) |
| throws MetastoreNotificationFetchException { |
| try (MetaStoreClient msClient = catalog_.getMetaStoreClient()) { |
| // fetch the current notification event id. We assume that the polling interval |
| // is small enough that most of these polling operations result in zero new |
| // events. In such a case, fetching current notification event id is much faster |
| // (and cheaper on HMS side) instead of polling for events directly |
| CurrentNotificationEventId currentNotificationEventId = |
| msClient.getHiveClient().getCurrentNotificationEventId(); |
| long currentEventId = currentNotificationEventId.getEventId(); |
| |
| // no new events since we last polled |
| if (currentEventId <= eventId) { |
| return Collections.emptyList(); |
| } |
| |
| NotificationEventResponse response = msClient.getHiveClient() |
| .getNextNotification(eventId, 1000, null); |
| return response.getEvents(); |
| } catch (TException e) { |
| throw new MetastoreNotificationFetchException( |
| "Unable to fetch notifications from metastore", e); |
| } |
| } |
| } |