org.elasticsearch.common.lucene.uid.PerThreadIDAndVersionLookup Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of elasticsearch Show documentation
Show all versions of elasticsearch Show documentation
Elasticsearch subproject :server
package org.elasticsearch.common.lucene.uid;
/*
* Licensed to Elasticsearch 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.
*/
import org.apache.lucene.index.Fields;
import org.apache.lucene.index.LeafReader;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.index.NumericDocValues;
import org.apache.lucene.index.PostingsEnum;
import org.apache.lucene.index.Terms;
import org.apache.lucene.index.TermsEnum;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.util.Bits;
import org.apache.lucene.util.BytesRef;
import org.elasticsearch.common.lucene.uid.Versions.DocIdAndVersion;
import org.elasticsearch.index.mapper.UidFieldMapper;
import org.elasticsearch.index.mapper.VersionFieldMapper;
import java.io.IOException;
/** Utility class to do efficient primary-key (only 1 doc contains the
* given term) lookups by segment, re-using the enums. This class is
* not thread safe, so it is the caller's job to create and use one
* instance of this per thread. Do not use this if a term may appear
* in more than one document! It will only return the first one it
* finds. */
final class PerThreadIDAndVersionLookup {
// TODO: do we really need to store all this stuff? some if it might not speed up anything.
// we keep it around for now, to reduce the amount of e.g. hash lookups by field and stuff
/** terms enum for uid field */
private final TermsEnum termsEnum;
/** _version data */
private final NumericDocValues versions;
/** Reused for iteration (when the term exists) */
private PostingsEnum docsEnum;
/**
* Initialize lookup for the provided segment
*/
public PerThreadIDAndVersionLookup(LeafReader reader) throws IOException {
TermsEnum termsEnum = null;
NumericDocValues versions = null;
Fields fields = reader.fields();
if (fields != null) {
Terms terms = fields.terms(UidFieldMapper.NAME);
if (terms != null) {
termsEnum = terms.iterator();
assert termsEnum != null;
versions = reader.getNumericDocValues(VersionFieldMapper.NAME);
assert versions != null;
}
}
this.versions = versions;
this.termsEnum = termsEnum;
}
/** Return null if id is not found. */
public DocIdAndVersion lookup(BytesRef id, Bits liveDocs, LeafReaderContext context) throws IOException {
if (termsEnum.seekExact(id)) {
// there may be more than one matching docID, in the case of nested docs, so we want the last one:
docsEnum = termsEnum.postings(docsEnum, 0);
int docID = DocIdSetIterator.NO_MORE_DOCS;
for (int d = docsEnum.nextDoc(); d != DocIdSetIterator.NO_MORE_DOCS; d = docsEnum.nextDoc()) {
if (liveDocs != null && liveDocs.get(d) == false) {
continue;
}
docID = d;
}
if (docID != DocIdSetIterator.NO_MORE_DOCS) {
return new DocIdAndVersion(docID, versions.get(docID), context);
}
}
return null;
}
}