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.regionserver.HRegion;
030import org.apache.hadoop.hbase.regionserver.RegionServerServices;
031import org.apache.hadoop.hbase.regionserver.RegionServerServices.RegionStateTransitionContext;
032import org.apache.yetus.audience.InterfaceAudience;
033import org.slf4j.Logger;
034import org.slf4j.LoggerFactory;
035import org.apache.hadoop.hbase.shaded.protobuf.generated.RegionServerStatusProtos.RegionStateTransition.TransitionCode;
036
037/**
038 * Handles closing of a region on a region server.
039 */
040@InterfaceAudience.Private
041public class CloseRegionHandler extends EventHandler {
042  // NOTE on priorities shutting down.  There are none for close. There are some
043  // for open.  I think that is right.  On shutdown, we want the meta to close
044  // after the user regions have closed.  What
045  // about the case where master tells us to shutdown a catalog region and we
046  // have a running queue of user regions to close?
047  private static final Logger LOG = LoggerFactory.getLogger(CloseRegionHandler.class);
048
049  private final RegionServerServices rsServices;
050  private final RegionInfo regionInfo;
051
052  // If true, the hosting server is aborting.  Region close process is different
053  // when we are aborting.
054  private final boolean abort;
055  private ServerName destination;
056
057  /**
058   * This method used internally by the RegionServer to close out regions.
059   * @param server
060   * @param rsServices
061   * @param regionInfo
062   * @param abort If the regionserver is aborting.
063   * @param destination
064   */
065  public CloseRegionHandler(final Server server,
066      final RegionServerServices rsServices,
067      final RegionInfo regionInfo, final boolean abort,
068      ServerName destination) {
069    this(server, rsServices, regionInfo, abort,
070      EventType.M_RS_CLOSE_REGION, destination);
071  }
072
073  protected CloseRegionHandler(final Server server,
074      final RegionServerServices rsServices, RegionInfo regionInfo,
075      boolean abort, EventType eventType, ServerName destination) {
076    super(server, eventType);
077    this.server = server;
078    this.rsServices = rsServices;
079    this.regionInfo = regionInfo;
080    this.abort = abort;
081    this.destination = destination;
082  }
083
084  public RegionInfo getRegionInfo() {
085    return regionInfo;
086  }
087
088  @Override
089  public void process() {
090    try {
091      String name = regionInfo.getEncodedName();
092      LOG.trace("Processing close of {}", name);
093      String encodedRegionName = regionInfo.getEncodedName();
094      // Check that this region is being served here
095      HRegion region = (HRegion)rsServices.getRegion(encodedRegionName);
096      if (region == null) {
097        LOG.warn("Received CLOSE for region {} but currently not serving - ignoring", name);
098        // TODO: do better than a simple warning
099        return;
100      }
101
102      // Close the region
103      try {
104        if (region.close(abort) == null) {
105          // This region got closed.  Most likely due to a split.
106          // The split message will clean up the master state.
107          LOG.warn("Can't close region {}, was already closed during close()", name);
108          return;
109        }
110      } catch (IOException ioe) {
111        // An IOException here indicates that we couldn't successfully flush the
112        // memstore before closing. So, we need to abort the server and allow
113        // the master to split our logs in order to recover the data.
114        server.abort("Unrecoverable exception while closing region " +
115          regionInfo.getRegionNameAsString() + ", still finishing close", ioe);
116        throw new RuntimeException(ioe);
117      }
118
119      this.rsServices.removeRegion(region, destination);
120      rsServices.reportRegionStateTransition(new RegionStateTransitionContext(TransitionCode.CLOSED,
121          HConstants.NO_SEQNUM, -1, regionInfo));
122
123      // Done!  Region is closed on this RS
124      LOG.debug("Closed " + region.getRegionInfo().getRegionNameAsString());
125    } finally {
126      this.rsServices.getRegionsInTransitionInRS().
127        remove(this.regionInfo.getEncodedNameAsBytes(), Boolean.FALSE);
128    }
129  }
130}