| /* |
| * 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.beam.runners.dataflow.worker.util.common.worker; |
| |
| import java.io.IOException; |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.TimeUnit; |
| import javax.annotation.Nullable; |
| import org.apache.beam.vendor.guava.v20_0.com.google.common.annotations.VisibleForTesting; |
| import org.apache.beam.vendor.guava.v20_0.com.google.common.base.Objects; |
| import org.apache.beam.vendor.guava.v20_0.com.google.common.base.Throwables; |
| import org.apache.beam.vendor.guava.v20_0.com.google.common.cache.CacheBuilder; |
| import org.apache.beam.vendor.guava.v20_0.com.google.common.cache.CacheLoader; |
| import org.apache.beam.vendor.guava.v20_0.com.google.common.cache.LoadingCache; |
| |
| /** A {@link ShuffleBatchReader} that caches batches as they're read. */ |
| public class CachingShuffleBatchReader implements ShuffleBatchReader { |
| private final ShuffleBatchReader reader; |
| @VisibleForTesting final LoadingCache<BatchRange, Batch> cache; |
| |
| /** Limit the size of the cache to 1000 batches. */ |
| private static final int MAXIMUM_BATCHES = 1000; |
| |
| // Ensure that batches in the cache are expired quickly |
| // for improved GC performance. |
| private static final long EXPIRE_AFTER_MS = 250; |
| |
| public CachingShuffleBatchReader( |
| ShuffleBatchReader shuffleReader, int maximumBatches, long expireAfterAccessMillis) { |
| this.reader = shuffleReader; |
| this.cache = |
| CacheBuilder.newBuilder() |
| .maximumSize(maximumBatches) |
| .expireAfterAccess(expireAfterAccessMillis, TimeUnit.MILLISECONDS) |
| .<BatchRange, Batch>build( |
| new CacheLoader<BatchRange, Batch>() { |
| @Override |
| public Batch load(BatchRange batchRange) throws Exception { |
| final Batch batch = |
| reader.read(batchRange.startPosition, batchRange.endPosition); |
| return batch; |
| } |
| }); |
| } |
| |
| public CachingShuffleBatchReader(ShuffleBatchReader shuffleReader) { |
| this(shuffleReader, MAXIMUM_BATCHES, EXPIRE_AFTER_MS); |
| } |
| |
| public CachingShuffleBatchReader(ShuffleBatchReader shuffleReader, int maximumBatches) { |
| this(shuffleReader, maximumBatches, EXPIRE_AFTER_MS); |
| } |
| |
| @Override |
| public Batch read(@Nullable ShufflePosition startPosition, @Nullable ShufflePosition endPosition) |
| throws IOException { |
| final BatchRange range = new BatchRange(startPosition, endPosition); |
| try { |
| return cache.get(range); |
| } catch (RuntimeException | ExecutionException e) { |
| Throwables.propagateIfPossible(e, IOException.class); |
| throw new RuntimeException("unexpected", e); |
| } |
| } |
| |
| /** The key for the entries stored in the batch cache. */ |
| static final class BatchRange { |
| @Nullable protected final ShufflePosition startPosition; |
| @Nullable protected final ShufflePosition endPosition; |
| |
| public BatchRange( |
| @Nullable ShufflePosition startPosition, @Nullable ShufflePosition endPosition) { |
| this.startPosition = startPosition; |
| this.endPosition = endPosition; |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| return o == this |
| || (o instanceof BatchRange |
| && Objects.equal(((BatchRange) o).startPosition, startPosition) |
| && Objects.equal(((BatchRange) o).endPosition, endPosition)); |
| } |
| |
| @Override |
| public int hashCode() { |
| return Objects.hashCode(startPosition, endPosition); |
| } |
| } |
| } |