Package org.apache.hadoop.hdfs.server.namenode.ha

Class RequestHedgingProxyProvider<T>

java.lang.Object

org.apache.hadoop.hdfs.server.namenode.ha.AbstractNNFailoverProxyProvider<T>

org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider<T>

org.apache.hadoop.hdfs.server.namenode.ha.RequestHedgingProxyProvider<T>

All Implemented Interfaces:

Closeable, AutoCloseable, org.apache.hadoop.io.retry.FailoverProxyProvider<T>

public class RequestHedgingProxyProvider<T>
extends ConfiguredFailoverProxyProvider<T>

A FailoverProxyProvider implementation that technically does not "failover" per-se. It constructs a wrapper proxy that sends the request to ALL underlying proxies simultaneously. It assumes the in an HA setup, there will be only one Active, and the active should respond faster than any configured standbys. Once it receive a response from any one of the configured proxies, outstanding requests to other proxies are immediately cancelled.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.hdfs.server.namenode.ha.AbstractNNFailoverProxyProvider

AbstractNNFailoverProxyProvider.NNProxyInfo<T>

Nested classes/interfaces inherited from interface org.apache.hadoop.io.retry.FailoverProxyProvider

org.apache.hadoop.io.retry.FailoverProxyProvider.ProxyInfo<T extends Object>

Field Summary

Fields

Modifier and Type	Field	Description
static final org.slf4j.Logger	LOG

Fields inherited from class org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider

proxies

Fields inherited from class org.apache.hadoop.hdfs.server.namenode.ha.AbstractNNFailoverProxyProvider

conf, factory, fallbackToSimpleAuth, ugi, xface

Constructor Summary

Constructors

Constructor	Description
RequestHedgingProxyProvider(org.apache.hadoop.conf.Configuration conf, URI uri, Class<T> xface, HAProxyFactory<T> proxyFactory)

Method Summary

Modifier and Type	Method	Description
org.apache.hadoop.io.retry.FailoverProxyProvider.ProxyInfo<T>	getProxy()	Lazily initialize the RPC proxy object.
void	performFailover(T currentProxy)

Methods inherited from class org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider

close, useLogicalURI

Methods inherited from class org.apache.hadoop.hdfs.server.namenode.ha.AbstractNNFailoverProxyProvider

createProxyIfNeeded, getFallbackToSimpleAuth, getInterface, getProxyAddresses, getRandomOrder, setFallbackToSimpleAuth

Methods inherited from class java.lang.Object

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

Field Details

LOG

public static final org.slf4j.Logger LOG

Constructor Details

RequestHedgingProxyProvider

public RequestHedgingProxyProvider(org.apache.hadoop.conf.Configuration conf,
 URI uri,
 Class<T> xface,
 HAProxyFactory<T> proxyFactory)

Method Details

getProxy

public org.apache.hadoop.io.retry.FailoverProxyProvider.ProxyInfo<T> getProxy()

Description copied from class: ConfiguredFailoverProxyProvider

Lazily initialize the RPC proxy object.

Specified by:

getProxy in interface org.apache.hadoop.io.retry.FailoverProxyProvider<T>

Overrides:

getProxy in class ConfiguredFailoverProxyProvider<T>

performFailover

public void performFailover(T currentProxy)

Specified by:

performFailover in interface org.apache.hadoop.io.retry.FailoverProxyProvider<T>

Overrides:

performFailover in class ConfiguredFailoverProxyProvider<T>