zacharymorn commented on a change in pull request #240: URL: https://github.com/apache/lucene/pull/240#discussion_r710742109
########## File path: lucene/core/src/java/org/apache/lucene/search/TopFieldCollectorManager.java ########## @@ -0,0 +1,177 @@ +/* + * 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.lucene.search; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.Collection; +import java.util.List; + +/** + * Create a TopFieldCollectorManager which uses a shared hit counter to maintain number of hits and + * a shared {@link MaxScoreAccumulator} to propagate the minimum score across segments if the + * primary sort is by relevancy. + * + * <p>Note that a new collectorManager should be created for each search due to its internal states. + */ +public class TopFieldCollectorManager implements CollectorManager<TopFieldCollector, TopFieldDocs> { + private final Sort sort; + private final int numHits; + private final FieldDoc after; + private final HitsThresholdChecker hitsThresholdChecker; + private final MaxScoreAccumulator minScoreAcc; + private final List<TopFieldCollector> collectors; + private final boolean supportsConcurrency; + private boolean collectorCreated; + + /** + * Creates a new {@link TopFieldCollectorManager} from the given arguments. + * + * <p><b>NOTE</b>: The instances returned by this method pre-allocate a full array of length + * <code>numHits</code>. + * + * @param sort the sort criteria (SortFields). + * @param numHits the number of results to collect. + * @param after the previous doc after which matching docs will be collected. + * @param totalHitsThreshold the number of docs to count accurately. If the query matches more + * than {@code totalHitsThreshold} hits then its hit count will be a lower bound. On the other + * hand if the query matches less than or exactly {@code totalHitsThreshold} hits then the hit + * count of the result will be accurate. {@link Integer#MAX_VALUE} may be used to make the hit + * count accurate, but this will also make query processing slower. + * @param supportsConcurrency to use thread-safe and slower internal states for count tracking. + */ + public TopFieldCollectorManager( + Sort sort, int numHits, FieldDoc after, int totalHitsThreshold, boolean supportsConcurrency) { + if (totalHitsThreshold < 0) { + throw new IllegalArgumentException( + "totalHitsThreshold must be >= 0, got " + totalHitsThreshold); + } + + this.sort = sort; + this.numHits = numHits; + this.after = after; + this.supportsConcurrency = supportsConcurrency; + this.hitsThresholdChecker = + supportsConcurrency + ? HitsThresholdChecker.createShared(Math.max(totalHitsThreshold, numHits)) + : HitsThresholdChecker.create(Math.max(totalHitsThreshold, numHits)); + this.minScoreAcc = supportsConcurrency ? new MaxScoreAccumulator() : null; + this.collectors = new ArrayList<>(); + } + + /** + * Creates a new {@link TopFieldCollectorManager} from the given arguments, with thread-safe + * internal states. + * + * <p><b>NOTE</b>: The instances returned by this method pre-allocate a full array of length + * <code>numHits</code>. + * + * @param sort the sort criteria (SortFields). + * @param numHits the number of results to collect. + * @param after the previous doc after which matching docs will be collected. + * @param totalHitsThreshold the number of docs to count accurately. If the query matches more + * than {@code totalHitsThreshold} hits then its hit count will be a lower bound. On the other + * hand if the query matches less than or exactly {@code totalHitsThreshold} hits then the hit + * count of the result will be accurate. {@link Integer#MAX_VALUE} may be used to make the hit + * count accurate, but this will also make query processing slower. + */ + public TopFieldCollectorManager(Sort sort, int numHits, FieldDoc after, int totalHitsThreshold) { + this(sort, numHits, after, totalHitsThreshold, true); + } + + /** + * Creates a new {@link TopFieldCollectorManager} from the given arguments, with thread-safe + * internal states. + * + * <p><b>NOTE</b>: The instances returned by this method pre-allocate a full array of length + * <code>numHits</code>. + * + * @param sort the sort criteria (SortFields). + * @param numHits the number of results to collect. + * @param totalHitsThreshold the number of docs to count accurately. If the query matches more + * than {@code totalHitsThreshold} hits then its hit count will be a lower bound. On the other + * hand if the query matches less than or exactly {@code totalHitsThreshold} hits then the hit + * count of the result will be accurate. {@link Integer#MAX_VALUE} may be used to make the hit + * count accurate, but this will also make query processing slower. + */ + public TopFieldCollectorManager(Sort sort, int numHits, int totalHitsThreshold) { + this(sort, numHits, null, totalHitsThreshold, true); + } + + @Override + public TopFieldCollector newCollector() { + if (collectorCreated && supportsConcurrency == false) { + throw new IllegalStateException( + "The instantiated TopFieldCollectorManager does not support concurrency, but multiple collectors are being created"); + } else { + collectorCreated = true; + } + + if (sort.fields.length == 0) { + throw new IllegalArgumentException("Sort must contain at least one field"); + } + + if (numHits <= 0) { + throw new IllegalArgumentException( + "numHits must be > 0; please use TotalHitCountCollector if you just need the total hit count"); + } + + FieldValueHitQueue<FieldValueHitQueue.Entry> queue = + FieldValueHitQueue.create(sort.fields, numHits); + + TopFieldCollector collector; + if (after == null) { + collector = + new TopFieldCollector.SimpleFieldCollector( + sort, queue, numHits, hitsThresholdChecker, minScoreAcc); + } else { + if (after.fields == null) { + throw new IllegalArgumentException( + "after.fields wasn't set; you must pass fillFields=true for the previous search"); + } + + if (after.fields.length != sort.getSort().length) { + throw new IllegalArgumentException( + "after.fields has " + + after.fields.length + + " values but sort has " + + sort.getSort().length); + } + + collector = + new TopFieldCollector.PagingFieldCollector( + sort, queue, after, numHits, hitsThresholdChecker, minScoreAcc); + } + + collectors.add(collector); + return collector; + } + + @Override + public TopFieldDocs reduce(Collection<TopFieldCollector> collectors) throws IOException { + final TopFieldDocs[] topDocs = new TopFieldDocs[collectors.size()]; + int i = 0; + for (TopFieldCollector collector : collectors) { + topDocs[i++] = collector.topDocs(); + } + return TopDocs.merge(sort, 0, numHits, topDocs); + } + + public List<TopFieldCollector> getCollectors() { Review comment: So this method was added to support early termination detection in tests like the following: ``` collectorManager.getCollectors().stream().anyMatch(TopFieldCollector::isEarlyTerminated) ``` I think Lucene users may have the need for this check as well? ########## File path: lucene/sandbox/src/test/org/apache/lucene/sandbox/search/TestLargeNumHitsTopDocsCollector.java ########## @@ -159,19 +159,18 @@ public void testNoPQHitsOrder() throws IOException { private void runNumHits(int numHits) throws IOException { IndexSearcher searcher = newSearcher(reader); LargeNumHitsTopDocsCollector largeCollector = new LargeNumHitsTopDocsCollector(numHits); - TopScoreDocCollector regularCollector = - TopScoreDocCollector.create(numHits, null, Integer.MAX_VALUE); + TopScoreDocCollectorManager regularCollector = + new TopScoreDocCollectorManager(numHits, Integer.MAX_VALUE); searcher.search(testQuery, largeCollector); - searcher.search(testQuery, regularCollector); + TopDocs topDocs = searcher.search(testQuery, regularCollector); Review comment: Updated. -- This is an automated message from the Apache Git Service. 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