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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.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.Lucene;
import org.elasticsearch.common.lucene.uid.VersionsAndSeqNoResolver.DocIdAndSeqNo;
import org.elasticsearch.common.lucene.uid.VersionsAndSeqNoResolver.DocIdAndVersion;
import org.elasticsearch.index.mapper.SeqNoFieldMapper;
import org.elasticsearch.index.mapper.VersionFieldMapper;
import java.io.IOException;
import static org.elasticsearch.index.seqno.SequenceNumbers.UNASSIGNED_PRIMARY_TERM;
import static org.elasticsearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
/** 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.
* This class uses live docs, so it should be cached based on the
* {@link org.apache.lucene.index.IndexReader#getReaderCacheHelper() reader cache helper}
* rather than the {@link LeafReader#getCoreCacheHelper() core cache helper}.
*/
final class PerThreadIDVersionAndSeqNoLookup {
// 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 */
final String uidField;
private final TermsEnum termsEnum;
/** Reused for iteration (when the term exists) */
private PostingsEnum docsEnum;
/** used for assertions to make sure class usage meets assumptions */
private final Object readerKey;
/**
* Initialize lookup for the provided segment
*/
PerThreadIDVersionAndSeqNoLookup(LeafReader reader, String uidField) throws IOException {
this.uidField = uidField;
final Terms terms = reader.terms(uidField);
if (terms == null) {
// If a segment contains only no-ops, it does not have _uid but has both _soft_deletes and _tombstone fields.
final NumericDocValues softDeletesDV = reader.getNumericDocValues(Lucene.SOFT_DELETES_FIELD);
final NumericDocValues tombstoneDV = reader.getNumericDocValues(SeqNoFieldMapper.TOMBSTONE_NAME);
// this is a special case when we pruned away all IDs in a segment since all docs are deleted.
final boolean allDocsDeleted = (softDeletesDV != null && reader.numDocs() == 0);
if ((softDeletesDV == null || tombstoneDV == null) && allDocsDeleted == false) {
throw new IllegalArgumentException("reader does not have _uid terms but not a no-op segment; " +
"_soft_deletes [" + softDeletesDV + "], _tombstone [" + tombstoneDV + "]");
}
termsEnum = null;
} else {
termsEnum = terms.iterator();
}
if (reader.getNumericDocValues(VersionFieldMapper.NAME) == null) {
throw new IllegalArgumentException("reader misses the [" + VersionFieldMapper.NAME + "] field; _uid terms [" + terms + "]");
}
Object readerKey = null;
assert (readerKey = reader.getCoreCacheHelper().getKey()) != null;
this.readerKey = readerKey;
}
/** Return null if id is not found.
* We pass the {@link LeafReaderContext} as an argument so that things
* still work with reader wrappers that hide some documents while still
* using the same cache key. Otherwise we'd have to disable caching
* entirely for these readers.
*/
public DocIdAndVersion lookupVersion(BytesRef id, boolean loadSeqNo, LeafReaderContext context)
throws IOException {
assert context.reader().getCoreCacheHelper().getKey().equals(readerKey) :
"context's reader is not the same as the reader class was initialized on.";
int docID = getDocID(id, context);
if (docID != DocIdSetIterator.NO_MORE_DOCS) {
final long seqNo;
final long term;
if (loadSeqNo) {
seqNo = readNumericDocValues(context.reader(), SeqNoFieldMapper.NAME, docID);
term = readNumericDocValues(context.reader(), SeqNoFieldMapper.PRIMARY_TERM_NAME, docID);
} else {
seqNo = UNASSIGNED_SEQ_NO;
term = UNASSIGNED_PRIMARY_TERM;
}
final long version = readNumericDocValues(context.reader(), VersionFieldMapper.NAME, docID);
return new DocIdAndVersion(docID, version, seqNo, term, context.reader(), context.docBase);
} else {
return null;
}
}
/**
* returns the internal lucene doc id for the given id bytes.
* {@link DocIdSetIterator#NO_MORE_DOCS} is returned if not found
* */
private int getDocID(BytesRef id, LeafReaderContext context) throws IOException {
// termsEnum can possibly be null here if this leaf contains only no-ops.
if (termsEnum != null && termsEnum.seekExact(id)) {
final Bits liveDocs = context.reader().getLiveDocs();
int docID = DocIdSetIterator.NO_MORE_DOCS;
// 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);
for (int d = docsEnum.nextDoc(); d != DocIdSetIterator.NO_MORE_DOCS; d = docsEnum.nextDoc()) {
if (liveDocs != null && liveDocs.get(d) == false) {
continue;
}
docID = d;
}
return docID;
} else {
return DocIdSetIterator.NO_MORE_DOCS;
}
}
private static long readNumericDocValues(LeafReader reader, String field, int docId) throws IOException {
final NumericDocValues dv = reader.getNumericDocValues(field);
if (dv == null || dv.advanceExact(docId) == false) {
assert false : "document [" + docId + "] does not have docValues for [" + field + "]";
throw new IllegalStateException("document [" + docId + "] does not have docValues for [" + field + "]");
}
return dv.longValue();
}
/** Return null if id is not found. */
DocIdAndSeqNo lookupSeqNo(BytesRef id, LeafReaderContext context) throws IOException {
assert context.reader().getCoreCacheHelper().getKey().equals(readerKey) :
"context's reader is not the same as the reader class was initialized on.";
final int docID = getDocID(id, context);
if (docID != DocIdSetIterator.NO_MORE_DOCS) {
final long seqNo = readNumericDocValues(context.reader(), SeqNoFieldMapper.NAME, docID);
return new DocIdAndSeqNo(docID, seqNo, context);
} else {
return null;
}
}
}