rkhachatryan commented on code in PR #19550: URL: https://github.com/apache/flink/pull/19550#discussion_r858799446
########## flink-dstl/flink-dstl-dfs/src/main/java/org/apache/flink/changelog/fs/ChangelogRegistryImpl.java: ########## @@ -0,0 +1,91 @@ +/* + * 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.flink.changelog.fs; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.runtime.state.PhysicalStateHandleID; +import org.apache.flink.runtime.state.StreamStateHandle; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import javax.annotation.concurrent.ThreadSafe; + +import java.util.Map; +import java.util.Set; +import java.util.UUID; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.CopyOnWriteArraySet; +import java.util.concurrent.Executor; + +@Internal +@ThreadSafe +class ChangelogRegistryImpl implements ChangelogRegistry { + private static final Logger LOG = LoggerFactory.getLogger(ChangelogRegistryImpl.class); + + private final Map<PhysicalStateHandleID, Set<UUID>> entries = new ConcurrentHashMap<>(); + private final Executor executor; + + public ChangelogRegistryImpl(Executor executor) { + this.executor = executor; + } + + @Override + public void startTracking(StreamStateHandle handle, Set<UUID> backendIDs) { + LOG.debug( + "start tracking state, key: {}, state: {}", + handle.getStreamStateHandleID(), + handle); + entries.put(handle.getStreamStateHandleID(), new CopyOnWriteArraySet<>(backendIDs)); + } + + @Override + public void stopTracking(StreamStateHandle handle) { + LOG.debug( + "stop tracking state, key: {}, state: {}", handle.getStreamStateHandleID(), handle); + entries.remove(handle.getStreamStateHandleID()); + } + + @Override + public void notUsed(StreamStateHandle handle, UUID backendId) { Review Comment: Good question. It is the client responsibility to call `notUsed` when it is actually safe to do so. This is achieved by calling `notUsed` on checkpoint **subsumption** notification. And when a checkpoint is subsumed, notification about its **completion** doesn't matter. And when there are several backends involved, it is the responsibility of the Registry to wait for `notUsed()` call from **all** backends before discarding the state (and not discard it if at least one called `stopTracking()`). -- 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]
