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/*
* SPDX-License-Identifier: Apache-2.0
*
* The OpenSearch Contributors require contributions made to
* this file be licensed under the Apache-2.0 license or a
* compatible open source license.
*/
/*
* 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.
*/
/*
* Modifications Copyright OpenSearch Contributors. See
* GitHub history for details.
*/
package org.opensearch.common.lucene.uid;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.LeafReader;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.index.Term;
import org.apache.lucene.util.CloseableThreadLocal;
import org.opensearch.common.util.concurrent.ConcurrentCollections;
import java.io.IOException;
import java.util.List;
import java.util.Objects;
import java.util.concurrent.ConcurrentMap;
/**
* Utility class to resolve the Lucene doc ID, version, seqNo and primaryTerms for a given uid.
*
* @opensearch.internal
*/
public final class VersionsAndSeqNoResolver {
static final ConcurrentMap> lookupStates =
ConcurrentCollections.newConcurrentMapWithAggressiveConcurrency();
// Evict this reader from lookupStates once it's closed:
private static final IndexReader.ClosedListener removeLookupState = key -> {
CloseableThreadLocal ctl = lookupStates.remove(key);
if (ctl != null) {
ctl.close();
}
};
private static PerThreadIDVersionAndSeqNoLookup[] getLookupState(IndexReader reader, String uidField) throws IOException {
// We cache on the top level
// This means cache entries have a shorter lifetime, maybe as low as 1s with the
// default refresh interval and a steady indexing rate, but on the other hand it
// proved to be cheaper than having to perform a CHM and a TL get for every segment.
// See https://github.com/elastic/elasticsearch/pull/19856.
IndexReader.CacheHelper cacheHelper = reader.getReaderCacheHelper();
CloseableThreadLocal ctl = lookupStates.get(cacheHelper.getKey());
if (ctl == null) {
// First time we are seeing this reader's core; make a new CTL:
ctl = new CloseableThreadLocal<>();
CloseableThreadLocal other = lookupStates.putIfAbsent(cacheHelper.getKey(), ctl);
if (other == null) {
// Our CTL won, we must remove it when the reader is closed:
cacheHelper.addClosedListener(removeLookupState);
} else {
// Another thread beat us to it: just use their CTL:
ctl = other;
}
}
PerThreadIDVersionAndSeqNoLookup[] lookupState = ctl.get();
if (lookupState == null) {
lookupState = new PerThreadIDVersionAndSeqNoLookup[reader.leaves().size()];
for (LeafReaderContext leaf : reader.leaves()) {
lookupState[leaf.ord] = new PerThreadIDVersionAndSeqNoLookup(leaf.reader(), uidField);
}
ctl.set(lookupState);
}
if (lookupState.length != reader.leaves().size()) {
throw new AssertionError("Mismatched numbers of leaves: " + lookupState.length + " != " + reader.leaves().size());
}
if (lookupState.length > 0 && Objects.equals(lookupState[0].uidField, uidField) == false) {
throw new AssertionError(
"Index does not consistently use the same uid field: [" + uidField + "] != [" + lookupState[0].uidField + "]"
);
}
return lookupState;
}
private VersionsAndSeqNoResolver() {}
/**
* Wraps an {@link LeafReaderContext}, a doc ID relative to the context doc base and a version.
*
* @opensearch.internal
*/
public static class DocIdAndVersion {
public final int docId;
public final long version;
public final long seqNo;
public final long primaryTerm;
public final LeafReader reader;
public final int docBase;
public DocIdAndVersion(int docId, long version, long seqNo, long primaryTerm, LeafReader reader, int docBase) {
this.docId = docId;
this.version = version;
this.seqNo = seqNo;
this.primaryTerm = primaryTerm;
this.reader = reader;
this.docBase = docBase;
}
}
/**
* Wraps an {@link LeafReaderContext}, a doc ID relative to the context doc base and a seqNo.
*
* @opensearch.internal
*/
public static class DocIdAndSeqNo {
public final int docId;
public final long seqNo;
public final LeafReaderContext context;
DocIdAndSeqNo(int docId, long seqNo, LeafReaderContext context) {
this.docId = docId;
this.seqNo = seqNo;
this.context = context;
}
}
/**
* Load the internal doc ID and version for the uid from the reader, returning
* - null if the uid wasn't found,
*
- a doc ID and a version otherwise
*
*/
public static DocIdAndVersion loadDocIdAndVersion(IndexReader reader, Term term, boolean loadSeqNo) throws IOException {
PerThreadIDVersionAndSeqNoLookup[] lookups = getLookupState(reader, term.field());
List leaves = reader.leaves();
// iterate backwards to optimize for the frequently updated documents
// which are likely to be in the last segments
for (int i = leaves.size() - 1; i >= 0; i--) {
final LeafReaderContext leaf = leaves.get(i);
PerThreadIDVersionAndSeqNoLookup lookup = lookups[leaf.ord];
DocIdAndVersion result = lookup.lookupVersion(term.bytes(), loadSeqNo, leaf);
if (result != null) {
return result;
}
}
return null;
}
/**
* Loads the internal docId and sequence number of the latest copy for a given uid from the provided reader.
* The result is either null or the live and latest version of the given uid.
*/
public static DocIdAndSeqNo loadDocIdAndSeqNo(IndexReader reader, Term term) throws IOException {
final PerThreadIDVersionAndSeqNoLookup[] lookups = getLookupState(reader, term.field());
final List leaves = reader.leaves();
// iterate backwards to optimize for the frequently updated documents
// which are likely to be in the last segments
for (int i = leaves.size() - 1; i >= 0; i--) {
final LeafReaderContext leaf = leaves.get(i);
final PerThreadIDVersionAndSeqNoLookup lookup = lookups[leaf.ord];
final DocIdAndSeqNo result = lookup.lookupSeqNo(term.bytes(), leaf);
if (result != null) {
return result;
}
}
return null;
}
}