snazy commented on code in PR #1844: URL: https://github.com/apache/polaris/pull/1844#discussion_r2282740241
########## service/common/src/main/java/org/apache/polaris/service/events/listeners/InMemoryBufferPolarisPersistenceEventListener.java: ########## @@ -0,0 +1,166 @@ +/* + * 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.polaris.service.events.listeners; + +import com.google.common.annotations.VisibleForTesting; +import io.smallrye.common.annotation.Identifier; +import jakarta.annotation.PostConstruct; +import jakarta.annotation.PreDestroy; +import jakarta.enterprise.context.ApplicationScoped; +import jakarta.inject.Inject; +import jakarta.ws.rs.container.ContainerRequestContext; +import jakarta.ws.rs.core.Context; +import java.time.Clock; +import java.time.Duration; +import java.time.temporal.ChronoUnit; +import java.util.ArrayList; +import java.util.UUID; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.ConcurrentLinkedQueue; +import java.util.concurrent.Executors; +import java.util.concurrent.Future; +import java.util.concurrent.ScheduledExecutorService; +import java.util.concurrent.TimeUnit; +import org.apache.polaris.core.PolarisCallContext; +import org.apache.polaris.core.context.CallContext; +import org.apache.polaris.core.entity.PolarisEvent; +import org.apache.polaris.core.persistence.MetaStoreManagerFactory; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** Event listener that buffers in memory and then dumps to persistence. */ +@ApplicationScoped +@Identifier("persistence-in-memory-buffer") +public class InMemoryBufferPolarisPersistenceEventListener extends PolarisPersistenceEventListener { + private static final Logger LOGGER = + LoggerFactory.getLogger(InMemoryBufferPolarisPersistenceEventListener.class); + private static final String REQUEST_ID_KEY = "requestId"; + private final MetaStoreManagerFactory metaStoreManagerFactory; + private final Clock clock; + + private final ConcurrentHashMap<String, ConcurrentLinkedQueue<EventAndContext>> buffer = + new ConcurrentHashMap<>(); + private final ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor(); + private final ConcurrentHashMap<Future<?>, Integer> futures = new ConcurrentHashMap<>(); + private final Duration timeToFlush; + private final int maxBufferSize; + + @Context ContainerRequestContext containerRequestContext; + + private record EventAndContext(PolarisEvent polarisEvent, PolarisCallContext callContext) {} + + @Inject + public InMemoryBufferPolarisPersistenceEventListener( + MetaStoreManagerFactory metaStoreManagerFactory, + Clock clock, + InMemoryBufferPersistenceListenerConfiguration eventListenerConfiguration) { + this.metaStoreManagerFactory = metaStoreManagerFactory; + this.clock = clock; + this.timeToFlush = + eventListenerConfiguration.bufferTime().orElse(Duration.of(30, ChronoUnit.SECONDS)); + this.maxBufferSize = eventListenerConfiguration.maxBufferSize().orElse(5); // 5 events default + } + + @PostConstruct + void start() { + futures.put( + executor.scheduleAtFixedRate( + this::runCleanup, 0, timeToFlush.toMillis(), TimeUnit.MILLISECONDS), + 1); + } + + void runCleanup() { + for (String realmId : buffer.keySet()) { + try { + checkAndFlushBufferIfNecessary(realmId); + } catch (Exception e) { + LOGGER.debug("Buffer checking task failed for realm ({}): {}", realmId, e); + } + } + // Clean up futures + try { + futures.keySet().removeIf(future -> future.isCancelled() || future.isDone()); + } catch (Exception e) { + LOGGER.debug("Futures reaper task failed."); + } + } + + @PreDestroy + void shutdown() { + futures.keySet().forEach(future -> future.cancel(false)); + executor.shutdownNow(); + } + + @Override + String getRequestId() { + if (containerRequestContext != null && containerRequestContext.hasProperty(REQUEST_ID_KEY)) { + return (String) containerRequestContext.getProperty(REQUEST_ID_KEY); + } + return UUID.randomUUID().toString(); + } + + @Override + void addToBuffer(PolarisEvent polarisEvent, CallContext callCtx) { + String realmId = callCtx.getRealmContext().getRealmIdentifier(); + + buffer + .computeIfAbsent(realmId, k -> new ConcurrentLinkedQueue<>()) + .add(new EventAndContext(polarisEvent, callCtx.getPolarisCallContext().copy())); + futures.put(executor.submit(() -> checkAndFlushBufferIfNecessary(realmId)), 1); + } + + @VisibleForTesting + public void checkAndFlushBufferIfNecessary(String realmId) { + ConcurrentLinkedQueue<EventAndContext> queue = buffer.get(realmId); + if (queue == null || queue.isEmpty()) { + return; + } + + // Given that we are using a ConcurrentLinkedQueue, this should not lock any calls to `add` on + // the queue. + synchronized (queue) { + // Double-check inside synchronized block + if (queue.isEmpty()) { + return; + } + + EventAndContext head = queue.peek(); + if (head == null) { + return; + } + + Duration elapsed = Duration.ofMillis(clock.millis() - head.polarisEvent.getTimestampMs()); Review Comment: Wall clock can drift and also jump. And that ruins all timeout calculations. -- 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: issues-unsubscr...@polaris.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
