findingrish commented on code in PR #17360: URL: https://github.com/apache/druid/pull/17360#discussion_r1805856486
########## processing/src/main/java/org/apache/druid/query/groupby/GroupByStatsProvider.java: ########## @@ -0,0 +1,94 @@ +/* + * 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.druid.query.groupby; + +import org.apache.druid.collections.BlockingPool; +import org.apache.druid.guice.annotations.Merging; +import org.apache.druid.query.groupby.epinephelinae.LimitedTemporaryStorage; + +import javax.inject.Inject; +import java.nio.ByteBuffer; +import java.util.Iterator; +import java.util.concurrent.ConcurrentLinkedQueue; +import java.util.concurrent.atomic.AtomicLong; + +/** + * Collects stats for group by queries like used merged buffer count, spilled bytes and group by resource acquisition time. + */ +public class GroupByStatsProvider +{ + private final AtomicLong groupByResourceAcquisitionTimeNs = new AtomicLong(0); + private final AtomicLong groupByResourceAcquisitionCount = new AtomicLong(0); + + private final BlockingPool<ByteBuffer> blockingPool; + private final ConcurrentLinkedQueue<LimitedTemporaryStorage> temporaryStorages; + + @Inject + public GroupByStatsProvider(@Merging BlockingPool<ByteBuffer> blockingPool) + { + this.blockingPool = blockingPool; + this.temporaryStorages = new ConcurrentLinkedQueue<>(); + } + + public synchronized void groupByResourceAcquisitionTimeNs(long delayNs) + { + groupByResourceAcquisitionTimeNs.addAndGet(delayNs); + groupByResourceAcquisitionCount.incrementAndGet(); + } + + public synchronized long getAndResetGroupByResourceAcquisitionStats() + { + long average = (groupByResourceAcquisitionTimeNs.get() / groupByResourceAcquisitionCount.get()); + + groupByResourceAcquisitionTimeNs.set(0); + groupByResourceAcquisitionCount.set(0); + + return average; + } + + public long getAcquiredMergeBufferCount() + { + return blockingPool.getUsedBufferCount(); + } + + public void registerTemporaryStorage(LimitedTemporaryStorage temporaryStorage) + { + temporaryStorages.add(temporaryStorage); + } + + public long getSpilledBytes() Review Comment: > Would the code double-count the stored bytes? Perhaps that is the intended behavior. Yes, that is the intention. It basically is reporting the amount of bytes spilled when the metric is emitted. > Regardless of this, I think that there should be metric (either this one after repurposing or a new one) which indicates the total size of the spilled data, per query. This will allow the admins to estimate whether the queries need a larger merge buffer and by how much. Makes sense, but this would be reported at the end of every query? -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
