001/**
002 *
003 * Licensed to the Apache Software Foundation (ASF) under one
004 * or more contributor license agreements.  See the NOTICE file
005 * distributed with this work for additional information
006 * regarding copyright ownership.  The ASF licenses this file
007 * to you under the Apache License, Version 2.0 (the
008 * "License"); you may not use this file except in compliance
009 * with the License.  You may obtain a copy of the License at
010 *
011 *     http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing, software
014 * distributed under the License is distributed on an "AS IS" BASIS,
015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016 * See the License for the specific language governing permissions and
017 * limitations under the License.
018 */
019package org.apache.hadoop.hbase.regionserver.handler;
020
021import java.io.IOException;
022
023import org.apache.hadoop.hbase.HConstants;
024import org.apache.hadoop.hbase.Server;
025import org.apache.hadoop.hbase.ServerName;
026import org.apache.hadoop.hbase.client.RegionInfo;
027import org.apache.hadoop.hbase.executor.EventHandler;
028import org.apache.hadoop.hbase.executor.EventType;
029import org.apache.hadoop.hbase.procedure2.Procedure;
030import org.apache.hadoop.hbase.regionserver.HRegion;
031import org.apache.hadoop.hbase.regionserver.RegionServerServices;
032import org.apache.hadoop.hbase.regionserver.RegionServerServices.RegionStateTransitionContext;
033import org.apache.yetus.audience.InterfaceAudience;
034import org.slf4j.Logger;
035import org.slf4j.LoggerFactory;
036import org.apache.hadoop.hbase.shaded.protobuf.generated.RegionServerStatusProtos.RegionStateTransition.TransitionCode;
037
038/**
039 * Handles closing of a region on a region server.
040 * <p/>
041 * Now for regular close region request, we will use {@link UnassignRegionHandler} instead. But when
042 * shutting down the region server, will also close regions and the related methods still use this
043 * class so we keep it here.
044 * @see UnassignRegionHandler
045 */
046@InterfaceAudience.Private
047public class CloseRegionHandler extends EventHandler {
048  // NOTE on priorities shutting down.  There are none for close. There are some
049  // for open.  I think that is right.  On shutdown, we want the meta to close
050  // after the user regions have closed.  What
051  // about the case where master tells us to shutdown a catalog region and we
052  // have a running queue of user regions to close?
053  private static final Logger LOG = LoggerFactory.getLogger(CloseRegionHandler.class);
054
055  private final RegionServerServices rsServices;
056  private final RegionInfo regionInfo;
057
058  // If true, the hosting server is aborting.  Region close process is different
059  // when we are aborting.
060  private final boolean abort;
061  private ServerName destination;
062
063  /**
064   * This method used internally by the RegionServer to close out regions.
065   * @param server
066   * @param rsServices
067   * @param regionInfo
068   * @param abort If the regionserver is aborting.
069   * @param destination
070   */
071  public CloseRegionHandler(final Server server,
072      final RegionServerServices rsServices,
073      final RegionInfo regionInfo, final boolean abort,
074      ServerName destination) {
075    this(server, rsServices, regionInfo, abort,
076      EventType.M_RS_CLOSE_REGION, destination);
077  }
078
079  protected CloseRegionHandler(final Server server,
080      final RegionServerServices rsServices, RegionInfo regionInfo,
081      boolean abort, EventType eventType, ServerName destination) {
082    super(server, eventType);
083    this.server = server;
084    this.rsServices = rsServices;
085    this.regionInfo = regionInfo;
086    this.abort = abort;
087    this.destination = destination;
088  }
089
090  public RegionInfo getRegionInfo() {
091    return regionInfo;
092  }
093
094  @Override
095  public void process() {
096    try {
097      String name = regionInfo.getEncodedName();
098      LOG.trace("Processing close of {}", name);
099      String encodedRegionName = regionInfo.getEncodedName();
100      // Check that this region is being served here
101      HRegion region = (HRegion)rsServices.getRegion(encodedRegionName);
102      if (region == null) {
103        LOG.warn("Received CLOSE for region {} but currently not serving - ignoring", name);
104        // TODO: do better than a simple warning
105        return;
106      }
107
108      // Close the region
109      try {
110        if (region.close(abort) == null) {
111          // This region got closed.  Most likely due to a split.
112          // The split message will clean up the master state.
113          LOG.warn("Can't close region {}, was already closed during close()", name);
114          return;
115        }
116      } catch (IOException ioe) {
117        // An IOException here indicates that we couldn't successfully flush the
118        // memstore before closing. So, we need to abort the server and allow
119        // the master to split our logs in order to recover the data.
120        server.abort("Unrecoverable exception while closing region " +
121          regionInfo.getRegionNameAsString() + ", still finishing close", ioe);
122        throw new RuntimeException(ioe);
123      }
124
125      this.rsServices.removeRegion(region, destination);
126      rsServices.reportRegionStateTransition(new RegionStateTransitionContext(TransitionCode.CLOSED,
127        HConstants.NO_SEQNUM, Procedure.NO_PROC_ID, -1, regionInfo));
128
129      // Done!  Region is closed on this RS
130      LOG.debug("Closed " + region.getRegionInfo().getRegionNameAsString());
131    } finally {
132      this.rsServices.getRegionsInTransitionInRS().
133        remove(this.regionInfo.getEncodedNameAsBytes(), Boolean.FALSE);
134    }
135  }
136}