curcur commented on a change in pull request #13648: URL: https://github.com/apache/flink/pull/13648#discussion_r508382240
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/io/network/partition/PipelinedApproximateSubpartition.java ########## @@ -0,0 +1,105 @@ +/* + * 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.io.network.partition; + +import org.apache.flink.annotation.VisibleForTesting; +import org.apache.flink.runtime.io.network.buffer.Buffer; +import org.apache.flink.runtime.io.network.buffer.BufferConsumerWithPartialRecordLength; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import static org.apache.flink.util.Preconditions.checkState; + +/** + * A pipelined in-memory only subpartition, which allows to reconnecting after failure. + * Only one view is allowed at a time to read teh subpartition. + */ +public class PipelinedApproximateSubpartition extends PipelinedSubpartition { + + private static final Logger LOG = LoggerFactory.getLogger(PipelinedApproximateSubpartition.class); + + private boolean isPartialBuffer = false; + + PipelinedApproximateSubpartition(int index, ResultPartition parent) { + super(index, parent); + } + + @Override + public PipelinedSubpartitionView createReadView(BufferAvailabilityListener availabilityListener) { + synchronized (buffers) { + checkState(!isReleased); + + // if the view is not released yet + if (readView != null) { + LOG.info("{} ReadView for Subpartition {} of {} has not been released!", + parent.getOwningTaskName(), getSubPartitionIndex(), parent.getPartitionId()); + releaseView(); + } + + LOG.debug("{}: Creating read view for subpartition {} of partition {}.", + parent.getOwningTaskName(), getSubPartitionIndex(), parent.getPartitionId()); + + readView = new PipelinedApproximateSubpartitionView(this, availabilityListener); + } + + return readView; + } + + @Override + Buffer buildSliceBuffer(BufferConsumerWithPartialRecordLength buffer) { + if (isPartialBuffer) { + isPartialBuffer = !buffer.cleanupPartialRecord(); + } + + return buffer.build(); + } + + void releaseView() { + LOG.info("Releasing view of subpartition {} of {}.", getSubPartitionIndex(), parent.getPartitionId()); + readView = null; Review comment: Would this possibly happen? > Thread1: call subpartition.createReadView() - create view1 > Thread2: obtain a reference to view1 It is not possible to access to view1 through a different thread, unless downstream reconnects, meaning either thread1 releases the view upon disconnecting from downstream or a different thread (thread2) reconnects and release the view; that would be guarded by the buffer lock as you suggested. > Thread1: call subpartition.createReadView() - create view2 > Thread2: call view1.releaseAllResources <-- nulls out subpartition.readView; view2 is now corrupt? same as above. ---------------------------------------------------------------- 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]
