jpountz commented on a change in pull request #904: LUCENE-8992: Share minimum score across segment in concurrent search URL: https://github.com/apache/lucene-solr/pull/904#discussion_r333518999
########## File path: lucene/core/src/java/org/apache/lucene/search/MaxScoreAccumulator.java ########## @@ -0,0 +1,89 @@ +/* + * 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.util.concurrent.atomic.LongAccumulator; + +/** + * Maintains the maximum score and its corresponding document id concurrently + */ +final class MaxScoreAccumulator { + static final int DEFAULT_INTERVAL = 1 << 10; + + // scores are always positive + final LongAccumulator acc = new LongAccumulator(Long::max, Long.MIN_VALUE); + + // non-final and visible for tests + long modInterval; + + MaxScoreAccumulator() { + this.modInterval = DEFAULT_INTERVAL; + } + + void accumulate(int docID, float score) { + assert docID >= 0 && score >= 0; + long encode = (((long) Float.floatToIntBits(score)) << 32) | (docID & 0xffffffffL); + acc.accumulate(encode); + } + + Result get() { + long value = acc.get(); + if (value == Long.MIN_VALUE) { + return null; + } + float score = Float.intBitsToFloat((int) (value >> 32)); + int docID = (int) value; + return new Result(docID, score); + } + + static class Result implements Comparable<Result> { Review comment: nit: maybe use a more descriptive name, e.g. `DocAndScore`? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
