rkhachatryan commented on a change in pull request #14838: URL: https://github.com/apache/flink/pull/14838#discussion_r573803391
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/state/StateChangelogHandleStreamImpl.java ########## @@ -0,0 +1,144 @@ +/* + * 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.runtime.state; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.runtime.state.filesystem.FileStateHandle; +import org.apache.flink.runtime.state.memory.ByteStreamStateHandle; +import org.apache.flink.util.CloseableIterator; +import org.apache.flink.util.ExceptionUtils; + +import javax.annotation.Nullable; + +import java.io.IOException; +import java.util.Iterator; +import java.util.List; + +/** {@link StateChangelogHandle} implementation based on {@link StreamStateHandle}. */ +@Internal +public final class StateChangelogHandleStreamImpl + implements StateChangelogHandle<StateChangelogHandleStreamImpl.StateChangeStreamReader> { + private static final long serialVersionUID = -8070326169926626355L; + + private final KeyGroupRange keyGroupRange; + /** NOTE: order is important as it reflects the order of changes. */ + private final List<Tuple2<StreamStateHandle, Long>> handlesAndOffsets; + + private transient SharedStateRegistry stateRegistry; + + public StateChangelogHandleStreamImpl( + List<Tuple2<StreamStateHandle, Long>> handlesAndOffsets, KeyGroupRange keyGroupRange) { + this.handlesAndOffsets = handlesAndOffsets; + this.keyGroupRange = keyGroupRange; + } + + @Override + public void registerSharedStates(SharedStateRegistry stateRegistry) { + this.stateRegistry = stateRegistry; + handlesAndOffsets.forEach( + handleAndOffset -> + stateRegistry.registerReference( + getKey(handleAndOffset.f0), handleAndOffset.f0)); + } + + @Override + public KeyGroupRange getKeyGroupRange() { + return keyGroupRange; + } + + @Nullable + @Override + public KeyedStateHandle getIntersection(KeyGroupRange keyGroupRange) { + KeyGroupRange offsets = keyGroupRange.getIntersection(keyGroupRange); + if (offsets.getNumberOfKeyGroups() == 0) { + return null; + } + return new StateChangelogHandleStreamImpl(handlesAndOffsets, offsets); + } + + @Override + public CloseableIterator<StateChange> getChanges(StateChangeStreamReader reader) { + return new CloseableIterator<StateChange>() { + private final Iterator<Tuple2<StreamStateHandle, Long>> handleIterator = + handlesAndOffsets.iterator(); + + private CloseableIterator<StateChange> current = CloseableIterator.empty(); + + @Override + public boolean hasNext() { + advance(); + return current.hasNext(); + } + + @Override + public StateChange next() { + advance(); + return current.next(); + } + + private void advance() { + while (!current.hasNext() && handleIterator.hasNext()) { + Tuple2<StreamStateHandle, Long> tuple2 = handleIterator.next(); + try { + current = reader.read(tuple2.f0, tuple2.f1); + } catch (IOException e) { + ExceptionUtils.rethrow(e); + } + } + } + + @Override + public void close() throws Exception { + current.close(); + } + }; + } + + @Override + public void discardState() { + handlesAndOffsets.forEach( + handleAndOffset -> stateRegistry.unregisterReference(getKey(handleAndOffset.f0))); + } + + @Override + public long getStateSize() { + return 0; + } + + private static SharedStateRegistryKey getKey(StreamStateHandle stateHandle) { Review comment: > Or multiple backends bundles state changes altogether in a file Exactly. For a single checkpoint, all backends of a single TM will put their changes into the same file. Reference count for that file will be `number of backends` initially. If we instead use backend.uuid as a key then refCount would be 1 and file would be deleted as soon as one of the backends dereferences it. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected]
