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MAPREDUCE-3813. Added a cache for resolved racks. Contributed by Vinod K V.

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git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1241209 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Arun Murthy 2012-02-06 22:06:58 +00:00
parent 28a2eb9d72
commit c6282df3e5
3 changed files with 82 additions and 1 deletions
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2
hadoop-mapreduce-project/CHANGES.txt
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@ -713,6 +713,8 @@ Release 0.23.1 - Unreleased
MAPREDUCE-3810. Performance tweaks - reduced logging in AM and defined
hascode/equals for ResourceRequest & Priority. (vinodkv via acmurthy)
MAPREDUCE-3813. Added a cache for resolved racks. (vinodkv via acmurthy)
Release 0.23.0 - 2011-11-01
INCOMPATIBLE CHANGES

10
hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/RackResolver.java
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@ -26,6 +26,7 @@
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.CommonConfigurationKeysPublic;
import org.apache.hadoop.net.CachedDNSToSwitchMapping;
import org.apache.hadoop.net.DNSToSwitchMapping;
import org.apache.hadoop.net.Node;
import org.apache.hadoop.net.NodeBase;
@ -50,7 +51,14 @@ public synchronized static void init(Configuration conf) {
try {
Constructor<? extends DNSToSwitchMapping> dnsToSwitchMappingConstructor
= dnsToSwitchMappingClass.getConstructor();
dnsToSwitchMapping = dnsToSwitchMappingConstructor.newInstance();
DNSToSwitchMapping newInstance =
dnsToSwitchMappingConstructor.newInstance();
// Wrap around the configured class with the Cached implementation so as
// to save on repetitive lookups.
// Check if the impl is already caching, to avoid double caching.
dnsToSwitchMapping =
((newInstance instanceof CachedDNSToSwitchMapping) ? newInstance
: new CachedDNSToSwitchMapping(newInstance));
} catch (Exception e) {
throw new RuntimeException(e);
}

71
hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/util/TestRackResolver.java Normal file
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@ -0,0 +1,71 @@
/**
* 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.yarn.util;
import java.util.ArrayList;
import java.util.List;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.CommonConfigurationKeysPublic;
import org.apache.hadoop.net.DNSToSwitchMapping;
import org.apache.hadoop.net.Node;
import org.junit.Assert;
import org.junit.Test;
public class TestRackResolver {
public static final class MyResolver implements DNSToSwitchMapping {
int numHost1 = 0;
@Override
public List<String> resolve(List<String> hostList) {
// Only one host at a time
Assert.assertTrue("hostList size is " + hostList.size(),
hostList.size() <= 1);
List<String> returnList = new ArrayList<String>();
if (hostList.isEmpty()) {
return returnList;
}
if (hostList.get(0).equals("host1")) {
numHost1++;
returnList.add("/rack1");
}
// I should not be reached again as RackResolver is supposed to do
// caching.
Assert.assertTrue(numHost1 <= 1);
return returnList;
}
}
@Test
public void testCaching() {
Configuration conf = new Configuration();
conf.setClass(
CommonConfigurationKeysPublic.NET_TOPOLOGY_NODE_SWITCH_MAPPING_IMPL_KEY,
MyResolver.class, DNSToSwitchMapping.class);
RackResolver.init(conf);
Node node = RackResolver.resolve("host1");
Assert.assertEquals("/rack1", node.getNetworkLocation());
node = RackResolver.resolve("host1");
Assert.assertEquals("/rack1", node.getNetworkLocation());
}
}