/** | |
* 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.contrib.index.mapred; | |
import java.io.IOException; | |
import java.util.Iterator; | |
import org.apache.commons.logging.Log; | |
import org.apache.commons.logging.LogFactory; | |
import org.apache.hadoop.mapred.JobConf; | |
import org.apache.hadoop.mapred.MapReduceBase; | |
import org.apache.hadoop.mapred.OutputCollector; | |
import org.apache.hadoop.mapred.Reducer; | |
import org.apache.hadoop.mapred.Reporter; | |
/** | |
* This combiner combines multiple intermediate forms into one intermediate | |
* form. More specifically, the input intermediate forms are a single-document | |
* ram index and/or a single delete term. An output intermediate form contains | |
* a multi-document ram index and/or multiple delete terms. | |
*/ | |
public class IndexUpdateCombiner extends MapReduceBase implements | |
Reducer<Shard, IntermediateForm, Shard, IntermediateForm> { | |
static final Log LOG = LogFactory.getLog(IndexUpdateCombiner.class); | |
IndexUpdateConfiguration iconf; | |
long maxSizeInBytes; | |
long nearMaxSizeInBytes; | |
/* (non-Javadoc) | |
* @see org.apache.hadoop.mapred.Reducer#reduce(java.lang.Object, java.util.Iterator, org.apache.hadoop.mapred.OutputCollector, org.apache.hadoop.mapred.Reporter) | |
*/ | |
public void reduce(Shard key, Iterator<IntermediateForm> values, | |
OutputCollector<Shard, IntermediateForm> output, Reporter reporter) | |
throws IOException { | |
String message = key.toString(); | |
IntermediateForm form = null; | |
while (values.hasNext()) { | |
IntermediateForm singleDocForm = values.next(); | |
long formSize = form == null ? 0 : form.totalSizeInBytes(); | |
long singleDocFormSize = singleDocForm.totalSizeInBytes(); | |
if (form != null && formSize + singleDocFormSize > maxSizeInBytes) { | |
closeForm(form, message); | |
output.collect(key, form); | |
form = null; | |
} | |
if (form == null && singleDocFormSize >= nearMaxSizeInBytes) { | |
output.collect(key, singleDocForm); | |
} else { | |
if (form == null) { | |
form = createForm(message); | |
} | |
form.process(singleDocForm); | |
} | |
} | |
if (form != null) { | |
closeForm(form, message); | |
output.collect(key, form); | |
} | |
} | |
private IntermediateForm createForm(String message) throws IOException { | |
LOG.info("Construct a form writer for " + message); | |
IntermediateForm form = new IntermediateForm(); | |
form.configure(iconf); | |
return form; | |
} | |
private void closeForm(IntermediateForm form, String message) | |
throws IOException { | |
form.closeWriter(); | |
LOG.info("Closed the form writer for " + message + ", form = " + form); | |
} | |
/* (non-Javadoc) | |
* @see org.apache.hadoop.mapred.MapReduceBase#configure(org.apache.hadoop.mapred.JobConf) | |
*/ | |
public void configure(JobConf job) { | |
iconf = new IndexUpdateConfiguration(job); | |
maxSizeInBytes = iconf.getMaxRAMSizeInBytes(); | |
nearMaxSizeInBytes = maxSizeInBytes - (maxSizeInBytes >>> 3); // 7/8 of max | |
} | |
/* (non-Javadoc) | |
* @see org.apache.hadoop.mapred.MapReduceBase#close() | |
*/ | |
public void close() throws IOException { | |
} | |
} |