somandal commented on code in PR #14894: URL: https://github.com/apache/pinot/pull/14894#discussion_r1927437593
########## pinot-segment-local/src/main/java/org/apache/pinot/segment/local/utils/SegmentPreprocessThrottler.java: ########## @@ -0,0 +1,139 @@ +/** + * 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.utils; + +import com.google.common.annotations.VisibleForTesting; +import java.util.Map; +import org.apache.pinot.common.concurrency.AdjustableSemaphore; +import org.apache.pinot.spi.config.provider.PinotClusterConfigChangeListener; +import org.apache.pinot.spi.utils.CommonConstants; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +/** + * Used to throttle the total concurrent index rebuilds that can happen on a given Pinot server. + * Code paths that do no need to rebuild the index or which don't happen on the server need not utilize this throttler. + */ +public class SegmentPreprocessThrottler implements PinotClusterConfigChangeListener { + private static final Logger LOGGER = LoggerFactory.getLogger(SegmentPreprocessThrottler.class); + + /** + * If _maxPreprocessConcurrency is <= 0, it means that the cluster is not configured to limit the number of + * index rebuilds that can be executed concurrently. This class sets the semaphore permit to be a large value + * in this scenario. + */ + private int _maxPreprocessConcurrency; + private boolean _relaxThrottling; + private volatile AdjustableSemaphore _semaphore; + + public SegmentPreprocessThrottler(int maxPreprocessConcurrency, boolean relaxThrottling) { + LOGGER.info("Initializing SegmentPreprocessThrottler, maxPreprocessConcurrency: {}, relaxThrottling: {}", + maxPreprocessConcurrency, relaxThrottling); + if (maxPreprocessConcurrency <= 0) { + int defaultSegmentPreprocessParallelism = + Integer.parseInt(CommonConstants.Helix.DEFAULT_MAX_SEGMENT_PREPROCESS_PARALLELISM); + LOGGER.warn("Max preprocess concurrency is negative: {}, resetting to {}", maxPreprocessConcurrency, + defaultSegmentPreprocessParallelism); + maxPreprocessConcurrency = defaultSegmentPreprocessParallelism; + } + _maxPreprocessConcurrency = maxPreprocessConcurrency; + _relaxThrottling = relaxThrottling; + + int relaxThrottlingThreshold = Math.max(_maxPreprocessConcurrency, + CommonConstants.Helix.DEFAULT_MAX_SEGMENT_PREPROCESS_PARALLELISM_BEFORE_SERVING_QUERIES); + int preprocessConcurrency = _maxPreprocessConcurrency; + if (relaxThrottling) { + preprocessConcurrency = relaxThrottlingThreshold; + LOGGER.info("Relax throttling enabled, setting preprocess concurrency to: {}", preprocessConcurrency); + } + _semaphore = new AdjustableSemaphore(preprocessConcurrency, true); + LOGGER.info("Created semaphore with available permits: {}", _semaphore.availablePermits()); + } + + public void resetThrottling() { Review Comment: good catch, i've made both of them synchronized. this will only be called once, but even then it can coincide with onChange and miss the updated value. -- 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
