chenboat commented on code in PR #13503: URL: https://github.com/apache/pinot/pull/13503#discussion_r1690197552
########## pinot-segment-local/src/main/java/org/apache/pinot/segment/local/realtime/impl/invertedindex/RealtimeLuceneIndexRefreshManager.java: ########## @@ -0,0 +1,268 @@ +/** + * 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.pinot.segment.local.realtime.impl.invertedindex; + +import com.google.common.annotations.VisibleForTesting; +import com.google.common.base.Preconditions; +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.ThreadPoolExecutor; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.locks.Lock; +import java.util.concurrent.locks.ReentrantLock; +import java.util.stream.Collectors; +import org.apache.lucene.search.SearcherManager; +import org.apache.pinot.common.utils.ScalingThreadPoolExecutor; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +/** + * This class manages the refreshing of all realtime Lucene index readers. It uses an auto-scaling pool of threads, + * which expands up to a configurable size, to refresh the readers. + * <p> + * During instantiation of a RealtimeLuceneTextIndex the corresponding SearcherManager is registered with this class. + * When the RealtimeLuceneTextIndex is closed, the flag set by the RealtimeLuceneTextIndex is checked before attempting + * a refresh, and SearcherManagerHolder instance previously registered to this class is dropped from the queue of + * readers to be refreshed. + */ +public class RealtimeLuceneIndexRefreshManager { + private static final Logger LOGGER = LoggerFactory.getLogger(RealtimeLuceneIndexRefreshManager.class); + // max number of parallel refresh threads + private final int _maxParallelism; + // delay between refresh iterations + private int _delayMs; + // partitioned lists of SearcherManagerHolders, each gets its own thread for refreshing. SearcherManagerHolders + // are added to the list with the smallest size to roughly balance the load across threads + private final List<List<SearcherManagerHolder>> _partitionedListsOfSearchers; + private static RealtimeLuceneIndexRefreshManager _singletonInstance; + private static ExecutorService _executorService; + + private RealtimeLuceneIndexRefreshManager(int maxParallelism, int delayMs) { + _maxParallelism = maxParallelism; + _delayMs = delayMs; + // Set min pool size to 0, scale up/down as needed. Set keep alive time to 0, as threads are generally long-lived + _executorService = ScalingThreadPoolExecutor.newScalingThreadPool(0, _maxParallelism, 0L); + _partitionedListsOfSearchers = new ArrayList<>(); + } + + public static RealtimeLuceneIndexRefreshManager getInstance() { Review Comment: Is this class thread safe? Why not add synchronized as the basic singleton method as suggested here as a common pattern? https://stackoverflow.com/questions/11165852/java-singleton-and-synchronization -- 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. To unsubscribe, e-mail: commits-unsubscr...@pinot.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@pinot.apache.org For additional commands, e-mail: commits-h...@pinot.apache.org
