org.apache.hadoop.hbase.client

Class AsyncMetaRegionLocator

java.lang.Object

org.apache.hadoop.hbase.client.AsyncMetaRegionLocator

@InterfaceAudience.Private
class AsyncMetaRegionLocator
extends Object

The asynchronous locator for meta region.

Field Summary

Fields

Modifier and Type	Field and Description
private static org.slf4j.Logger	LOG
private AtomicReference<RegionLocations>	metaRegionLocations
private AtomicReference<CompletableFuture<RegionLocations>>	metaRelocateFuture
private AsyncRegistry	registry

Constructor Summary

Constructors

Constructor and Description
AsyncMetaRegionLocator(AsyncRegistry registry)

Method Summary

Modifier and Type	Method and Description
private void	addLocationToCache(HRegionLocation loc)
(package private) void	clearCache()
private HRegionLocation	getCacheLocation(HRegionLocation loc)
(package private) CompletableFuture<RegionLocations>	getRegionLocations(int replicaId, boolean reload) Get the region locations for meta region.
private void	removeLocationFromCache(HRegionLocation loc)
(package private) void	updateCachedLocationOnError(HRegionLocation loc, Throwable exception)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOG

private static final org.slf4j.Logger LOG

registry

private final AsyncRegistry registry

metaRegionLocations

private final AtomicReference<RegionLocations> metaRegionLocations

metaRelocateFuture

private final AtomicReference<CompletableFuture<RegionLocations>> metaRelocateFuture

Constructor Detail

AsyncMetaRegionLocator

AsyncMetaRegionLocator(AsyncRegistry registry)

Method Detail

getRegionLocations

CompletableFuture<RegionLocations> getRegionLocations(int replicaId,
                                                      boolean reload)

Get the region locations for meta region. If the location for the given replica is not available in the cached locations, then fetch from the HBase cluster.

The replicaId parameter is important. If the region replication config for meta region is changed, then the cached region locations may not have the locations for new replicas. If we do not check the location for the given replica, we will always return the cached region locations and cause an infinite loop.

getCacheLocation

private HRegionLocation getCacheLocation(HRegionLocation loc)

addLocationToCache

private void addLocationToCache(HRegionLocation loc)

removeLocationFromCache

private void removeLocationFromCache(HRegionLocation loc)

updateCachedLocationOnError

void updateCachedLocationOnError(HRegionLocation loc,
                                 Throwable exception)

clearCache

void clearCache()