org.elasticsearch.index.codec.postingsformat.PulsingPostingsFormatProvider Maven / Gradle / Ivy
/*
* Licensed to ElasticSearch and Shay Banon under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. ElasticSearch 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.elasticsearch.index.codec.postingsformat;
import org.apache.lucene.codecs.BlockTreeTermsWriter;
import org.apache.lucene.codecs.PostingsFormat;
import org.apache.lucene.codecs.pulsing.Pulsing41PostingsFormat;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.inject.assistedinject.Assisted;
import org.elasticsearch.common.settings.Settings;
/**
* A {@link PostingsFormatProvider} for Lucenes {@link Pulsing41PostingsFormat}.
* The pulsing implementation in-lines the posting lists for very low frequent
* terms in the term dictionary. This is useful to improve lookup performance
* for low-frequent terms. This postings format offers the following parameters:
*
* - min_block_size: the minimum block size the default Lucene term
* dictionary uses to encode on-disk blocks.
*
* - max_block_size: the maximum block size the default Lucene term
* dictionary uses to encode on-disk blocks.
*
* - freq_cut_off: the document frequency cut off where pulsing
* in-lines posting lists into the term dictionary. Terms with a document
* frequency less or equal to the cutoff will be in-lined. The default is
* 1
*
*/
// LUCENE UPGRADE: Check if type of field postingsFormat needs to be updated!
public class PulsingPostingsFormatProvider extends AbstractPostingsFormatProvider {
private final int freqCutOff;
private final int minBlockSize;
private final int maxBlockSize;
private final Pulsing41PostingsFormat postingsFormat;
@Inject
public PulsingPostingsFormatProvider(@Assisted String name, @Assisted Settings postingsFormatSettings) {
super(name);
this.freqCutOff = postingsFormatSettings.getAsInt("freq_cut_off", 1);
this.minBlockSize = postingsFormatSettings.getAsInt("min_block_size", BlockTreeTermsWriter.DEFAULT_MIN_BLOCK_SIZE);
this.maxBlockSize = postingsFormatSettings.getAsInt("max_block_size", BlockTreeTermsWriter.DEFAULT_MAX_BLOCK_SIZE);
this.postingsFormat = new Pulsing41PostingsFormat(freqCutOff, minBlockSize, maxBlockSize);
}
public int freqCutOff() {
return freqCutOff;
}
public int minBlockSize() {
return minBlockSize;
}
public int maxBlockSize() {
return maxBlockSize;
}
@Override
public PostingsFormat get() {
return postingsFormat;
}
}