org.apache.hadoop.hbase.client.RegionLocator Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
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*
* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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package org.apache.hadoop.hbase.client;
import java.io.Closeable;
import java.io.IOException;
import java.util.List;
import java.util.stream.Collectors;
import org.apache.hadoop.hbase.HRegionLocation;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.util.Pair;
import org.apache.yetus.audience.InterfaceAudience;
/**
* Used to view region location information for a single HBase table. Obtain an instance from an
* {@link Connection}.
* @see ConnectionFactory
* @see Connection
* @see Table
* @since 0.99.0
*/
@InterfaceAudience.Public
public interface RegionLocator extends Closeable {
/**
* Configuration for Region Locator's mode when meta replica is configured. Valid values are:
* HedgedRead, LoadBalance, None
*/
String LOCATOR_META_REPLICAS_MODE = "hbase.locator.meta.replicas.mode";
/**
* Configuration for meta replica selector when Region Locator's LoadBalance mode is configured.
* The default value is org.apache.hadoop.hbase.client.CatalogReplicaLoadBalanceSimpleSelector.
*/
String LOCATOR_META_REPLICAS_MODE_LOADBALANCE_SELECTOR =
"hbase.locator.meta.replicas.mode.loadbalance.selector";
/**
* Finds the region on which the given row is being served. Does not reload the cache.
* @param row Row to find.
* @return Location of the row.
* @throws IOException if a remote or network exception occurs
*/
default HRegionLocation getRegionLocation(byte[] row) throws IOException {
return getRegionLocation(row, false);
}
/**
* Finds the region on which the given row is being served.
* @param row Row to find.
* @param reload true to reload information or false to use cached information
* @return Location of the row.
* @throws IOException if a remote or network exception occurs
*/
default HRegionLocation getRegionLocation(byte[] row, boolean reload) throws IOException {
return getRegionLocation(row, RegionInfo.DEFAULT_REPLICA_ID, reload);
}
/**
* Finds the region with the given replica id on which the given row is being served.
* @param row Row to find.
* @param replicaId the replica id
* @return Location of the row.
* @throws IOException if a remote or network exception occurs
*/
default HRegionLocation getRegionLocation(byte[] row, int replicaId) throws IOException {
return getRegionLocation(row, replicaId, false);
}
/**
* Finds the region with the given replica id on which the given row is being served.
* @param row Row to find.
* @param replicaId the replica id
* @param reload true to reload information or false to use cached information
* @return Location of the row.
* @throws IOException if a remote or network exception occurs
*/
HRegionLocation getRegionLocation(byte[] row, int replicaId, boolean reload) throws IOException;
/**
* Find all the replicas for the region on which the given row is being served.
* @param row Row to find.
* @return Locations for all the replicas of the row.
* @throws IOException if a remote or network exception occurs
*/
default List getRegionLocations(byte[] row) throws IOException {
return getRegionLocations(row, false);
}
/**
* Find all the replicas for the region on which the given row is being served.
* @param row Row to find.
* @param reload true to reload information or false to use cached information
* @return Locations for all the replicas of the row.
* @throws IOException if a remote or network exception occurs
*/
List getRegionLocations(byte[] row, boolean reload) throws IOException;
/**
* Clear all the entries in the region location cache.
*
* This may cause performance issue so use it with caution.
*/
void clearRegionLocationCache();
/**
* Retrieves all of the regions associated with this table.
*
* Usually we will go to meta table directly in this method so there is no {@code reload}
* parameter.
*
* Notice that the location for region replicas other than the default replica are also returned.
* @return a {@link List} of all regions associated with this table.
* @throws IOException if a remote or network exception occurs
*/
List getAllRegionLocations() throws IOException;
/**
* Gets the starting row key for every region in the currently open table.
*
* This is mainly useful for the MapReduce integration.
* @return Array of region starting row keys
* @throws IOException if a remote or network exception occurs
*/
default byte[][] getStartKeys() throws IOException {
return getStartEndKeys().getFirst();
}
/**
* Gets the ending row key for every region in the currently open table.
*
* This is mainly useful for the MapReduce integration.
* @return Array of region ending row keys
* @throws IOException if a remote or network exception occurs
*/
default byte[][] getEndKeys() throws IOException {
return getStartEndKeys().getSecond();
}
/**
* Gets the starting and ending row keys for every region in the currently open table.
*
* This is mainly useful for the MapReduce integration.
* @return Pair of arrays of region starting and ending row keys
* @throws IOException if a remote or network exception occurs
*/
default Pair getStartEndKeys() throws IOException {
List regions = getAllRegionLocations().stream()
.filter(loc -> RegionReplicaUtil.isDefaultReplica(loc.getRegion()))
.collect(Collectors.toList());
byte[][] startKeys = new byte[regions.size()][];
byte[][] endKeys = new byte[regions.size()][];
for (int i = 0, n = regions.size(); i < n; i++) {
RegionInfo region = regions.get(i).getRegion();
startKeys[i] = region.getStartKey();
endKeys[i] = region.getEndKey();
}
return Pair.newPair(startKeys, endKeys);
}
/**
* Gets the fully qualified table name instance of this table.
*/
TableName getName();
}