/**
* Copyright The Apache Software Foundation
*
* 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.hadoop.hbase.master.handler;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.RegionLoad;
import org.apache.hadoop.hbase.ServerLoad;
import org.apache.hadoop.hbase.ServerName;
import org.apache.hadoop.hbase.exceptions.RegionOpeningException;
import org.apache.hadoop.hbase.executor.EventHandler;
import org.apache.hadoop.hbase.executor.EventType;
import org.apache.hadoop.hbase.master.CatalogJanitor;
import org.apache.hadoop.hbase.master.MasterServices;
import org.apache.hadoop.hbase.master.RegionPlan;
import org.apache.hadoop.hbase.master.RegionStates;
import org.apache.hadoop.hbase.master.ServerManager;
import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
/**
* Handles MERGE regions request on master: move the regions together(on the
* same regionserver) and send MERGE RPC to regionserver.
*
* NOTE:The real merge is executed on the regionserver
*
*/
@InterfaceAudience.Private
public class DispatchMergingRegionHandler extends EventHandler {
private static final Log LOG = LogFactory.getLog(DispatchMergingRegionHandler.class);
private final MasterServices masterServices;
private final CatalogJanitor catalogJanitor;
private HRegionInfo region_a;
private HRegionInfo region_b;
private final boolean forcible;
private final int timeout;
public DispatchMergingRegionHandler(final MasterServices services,
final CatalogJanitor catalogJanitor, final HRegionInfo region_a,
final HRegionInfo region_b, final boolean forcible) {
super(services, EventType.C_M_MERGE_REGION);
this.masterServices = services;
this.catalogJanitor = catalogJanitor;
this.region_a = region_a;
this.region_b = region_b;
this.forcible = forcible;
this.timeout = server.getConfiguration().getInt(
"hbase.master.regionmerge.timeout", 120 * 1000);
}
@Override
public void process() throws IOException {
boolean regionAHasMergeQualifier = !catalogJanitor.cleanMergeQualifier(region_a);
if (regionAHasMergeQualifier
|| !catalogJanitor.cleanMergeQualifier(region_b)) {
LOG.info("Skip merging regions " + region_a.getRegionNameAsString()
+ ", " + region_b.getRegionNameAsString() + ", because region "
+ (regionAHasMergeQualifier ? region_a.getEncodedName() : region_b
.getEncodedName()) + " has merge qualifier");
return;
}
RegionStates regionStates = masterServices.getAssignmentManager()
.getRegionStates();
ServerName region_a_location = regionStates.getRegionServerOfRegion(region_a);
ServerName region_b_location = regionStates.getRegionServerOfRegion(region_b);
if (region_a_location == null || region_b_location == null) {
LOG.info("Skip merging regions " + region_a.getRegionNameAsString()
+ ", " + region_b.getRegionNameAsString() + ", because region "
+ (region_a_location == null ? region_a.getEncodedName() : region_b
.getEncodedName()) + " is not online now");
return;
}
long startTime = EnvironmentEdgeManager.currentTime();
boolean onSameRS = region_a_location.equals(region_b_location);
// Make sure regions are on the same regionserver before send merge
// regions request to regionserver
if (!onSameRS) {
// Move region_b to region a's location, switch region_a and region_b if
// region_a's load lower than region_b's, so we will always move lower
// load region
RegionLoad loadOfRegionA = getRegionLoad(region_a_location, region_a);
RegionLoad loadOfRegionB = getRegionLoad(region_b_location, region_b);
if (loadOfRegionA != null && loadOfRegionB != null
&& loadOfRegionA.getRequestsCount() < loadOfRegionB
.getRequestsCount()) {
// switch region_a and region_b
HRegionInfo tmpRegion = this.region_a;
this.region_a = this.region_b;
this.region_b = tmpRegion;
ServerName tmpLocation = region_a_location;
region_a_location = region_b_location;
region_b_location = tmpLocation;
}
RegionPlan regionPlan = new RegionPlan(region_b, region_b_location,
region_a_location);
LOG.info("Moving regions to same server for merge: " + regionPlan.toString());
masterServices.getAssignmentManager().balance(regionPlan);
while (!masterServices.isStopped()) {
try {
Thread.sleep(20);
// Make sure check RIT first, then get region location, otherwise
// we would make a wrong result if region is online between getting
// region location and checking RIT
boolean isRIT = regionStates.isRegionInTransition(region_b);
region_b_location = masterServices.getAssignmentManager()
.getRegionStates().getRegionServerOfRegion(region_b);
onSameRS = region_a_location.equals(region_b_location);
if (onSameRS || !isRIT) {
// Regions are on the same RS, or region_b is not in
// RegionInTransition any more
break;
}
if ((EnvironmentEdgeManager.currentTime() - startTime) > timeout) break;
} catch (InterruptedException e) {
InterruptedIOException iioe = new InterruptedIOException();
iioe.initCause(e);
throw iioe;
}
}
}
if (onSameRS) {
startTime = EnvironmentEdgeManager.currentTime();
while (!masterServices.isStopped()) {
try {
masterServices.getServerManager().sendRegionsMerge(region_a_location,
region_a, region_b, forcible);
LOG.info("Sent merge to server " + region_a_location + " for region " +
region_a.getEncodedName() + "," + region_b.getEncodedName() + ", focible=" + forcible);
break;
} catch (RegionOpeningException roe) {
if ((EnvironmentEdgeManager.currentTime() - startTime) > timeout) {
LOG.warn("Failed sending merge to " + region_a_location + " after " + timeout + "ms",
roe);
break;
}
// Do a retry since region should be online on RS immediately
} catch (IOException ie) {
LOG.warn("Failed sending merge to " + region_a_location + " for region " +
region_a.getEncodedName() + "," + region_b.getEncodedName() + ", focible=" + forcible,
ie);
break;
}
}
} else {
LOG.info("Cancel merging regions " + region_a.getRegionNameAsString()
+ ", " + region_b.getRegionNameAsString()
+ ", because can't move them together after "
+ (EnvironmentEdgeManager.currentTime() - startTime) + "ms");
}
}
private RegionLoad getRegionLoad(ServerName sn, HRegionInfo hri) {
ServerManager serverManager = masterServices.getServerManager();
ServerLoad load = serverManager.getLoad(sn);
if (load != null) {
Map<byte[], RegionLoad> regionsLoad = load.getRegionsLoad();
if (regionsLoad != null) {
return regionsLoad.get(hri.getRegionName());
}
}
return null;
}
}