org.apache.hadoop.hbase.client.RegionReplicaUtil Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* 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.client;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.yetus.audience.InterfaceAudience;
/**
* Utility methods which contain the logic for regions and replicas.
*/
@InterfaceAudience.Private
public class RegionReplicaUtil {
/**
* Whether or not the secondary region will wait for observing a flush / region open event
* from the primary region via async wal replication before enabling read requests. Since replayed
* edits from async wal replication from primary is not persisted in WAL, the memstore of the
* secondary region might be non-empty at the time of close or crash. For ensuring seqId's not
* "going back in time" in the secondary region replica, this should be enabled. However, in some
* cases the above semantics might be ok for some application classes.
* See HBASE-11580 for more context.
*/
public static final String REGION_REPLICA_WAIT_FOR_PRIMARY_FLUSH_CONF_KEY
= "hbase.region.replica.wait.for.primary.flush";
protected static final boolean DEFAULT_REGION_REPLICA_WAIT_FOR_PRIMARY_FLUSH = true;
/**
* The default replicaId for the region
*/
static final int DEFAULT_REPLICA_ID = 0;
/**
* Returns the RegionInfo for the given replicaId.
* RegionInfo's correspond to a range of a table, but more than one
* "instance" of the same range can be deployed which are differentiated by
* the replicaId.
* @param regionInfo
* @param replicaId the replicaId to use
* @return an RegionInfo object corresponding to the same range (table, start and
* end key), but for the given replicaId.
*/
public static RegionInfo getRegionInfoForReplica(RegionInfo regionInfo, int replicaId) {
if (regionInfo.getReplicaId() == replicaId) {
return regionInfo;
}
if (regionInfo.isMetaRegion()) {
return RegionInfoBuilder.newBuilder(regionInfo.getTable())
.setRegionId(regionInfo.getRegionId())
.setReplicaId(replicaId)
.setOffline(regionInfo.isOffline())
.build();
} else {
return RegionInfoBuilder.newBuilder(regionInfo.getTable())
.setStartKey(regionInfo.getStartKey())
.setEndKey(regionInfo.getEndKey())
.setSplit(regionInfo.isSplit())
.setRegionId(regionInfo.getRegionId())
.setReplicaId(replicaId)
.setOffline(regionInfo.isOffline())
.build();
}
}
/**
* Returns the RegionInfo for the default replicaId (0). RegionInfo's correspond to
* a range of a table, but more than one "instance" of the same range can be
* deployed which are differentiated by the replicaId.
* @return an RegionInfo object corresponding to the same range (table, start and
* end key), but for the default replicaId.
*/
public static RegionInfo getRegionInfoForDefaultReplica(RegionInfo regionInfo) {
return getRegionInfoForReplica(regionInfo, DEFAULT_REPLICA_ID);
}
/** @return true if this replicaId corresponds to default replica for the region */
public static boolean isDefaultReplica(int replicaId) {
return DEFAULT_REPLICA_ID == replicaId;
}
/** @return true if this region is a default replica for the region */
public static boolean isDefaultReplica(RegionInfo hri) {
return hri.getReplicaId() == DEFAULT_REPLICA_ID;
}
/**
* Removes the non-default replicas from the passed regions collection
* @param regions
*/
public static void removeNonDefaultRegions(Collection regions) {
Iterator iterator = regions.iterator();
while (iterator.hasNext()) {
RegionInfo hri = iterator.next();
if (!RegionReplicaUtil.isDefaultReplica(hri)) {
iterator.remove();
}
}
}
public static boolean isReplicasForSameRegion(RegionInfo regionInfoA, RegionInfo regionInfoB) {
return compareRegionInfosWithoutReplicaId(regionInfoA, regionInfoB) == 0;
}
private static int compareRegionInfosWithoutReplicaId(RegionInfo regionInfoA,
RegionInfo regionInfoB) {
int result = regionInfoA.getTable().compareTo(regionInfoB.getTable());
if (result != 0) {
return result;
}
// Compare start keys.
result = Bytes.compareTo(regionInfoA.getStartKey(), regionInfoB.getStartKey());
if (result != 0) {
return result;
}
// Compare end keys.
result = Bytes.compareTo(regionInfoA.getEndKey(), regionInfoB.getEndKey());
if (result != 0) {
if (regionInfoA.getStartKey().length != 0
&& regionInfoA.getEndKey().length == 0) {
return 1; // this is last region
}
if (regionInfoB.getStartKey().length != 0
&& regionInfoB.getEndKey().length == 0) {
return -1; // o is the last region
}
return result;
}
// regionId is usually milli timestamp -- this defines older stamps
// to be "smaller" than newer stamps in sort order.
if (regionInfoA.getRegionId() > regionInfoB.getRegionId()) {
return 1;
} else if (regionInfoA.getRegionId() < regionInfoB.getRegionId()) {
return -1;
}
return 0;
}
/**
* Create any replicas for the regions (the default replicas that was already created is passed to
* the method)
* @param tableDescriptor descriptor to use
* @param regions existing regions
* @param oldReplicaCount existing replica count
* @param newReplicaCount updated replica count due to modify table
* @return the combined list of default and non-default replicas
*/
public static List addReplicas(final TableDescriptor tableDescriptor,
final List regions, int oldReplicaCount, int newReplicaCount) {
if ((newReplicaCount - 1) <= 0) {
return regions;
}
List hRegionInfos = new ArrayList<>((newReplicaCount) * regions.size());
for (int i = 0; i < regions.size(); i++) {
if (RegionReplicaUtil.isDefaultReplica(regions.get(i))) {
// region level replica index starts from 0. So if oldReplicaCount was 2 then the max replicaId for
// the existing regions would be 1
for (int j = oldReplicaCount; j < newReplicaCount; j++) {
hRegionInfos.add(RegionReplicaUtil.getRegionInfoForReplica(regions.get(i), j));
}
}
}
hRegionInfos.addAll(regions);
return hRegionInfos;
}
}