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https://issues.apache.org/jira/browse/HADOOP-18291?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17739428#comment-17739428
]
ASF GitHub Bot commented on HADOOP-18291:
-----------------------------------------
virajjasani commented on code in PR #5754:
URL: https://github.com/apache/hadoop/pull/5754#discussion_r1249984399
##########
hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/s3a/ITestS3APrefetchingLruEviction.java:
##########
@@ -0,0 +1,241 @@
+/*
+ * 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.hadoop.fs.s3a;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.net.URI;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+import
org.apache.hadoop.thirdparty.com.google.common.util.concurrent.ThreadFactoryBuilder;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FSDataInputStream;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.s3a.performance.AbstractS3ACostTest;
+import org.apache.hadoop.fs.statistics.IOStatistics;
+import org.apache.hadoop.test.LambdaTestUtils;
+
+import static org.apache.hadoop.fs.s3a.Constants.PREFETCH_BLOCK_DEFAULT_SIZE;
+import static org.apache.hadoop.fs.s3a.Constants.PREFETCH_BLOCK_SIZE_KEY;
+import static org.apache.hadoop.fs.s3a.Constants.PREFETCH_ENABLED_KEY;
+import static org.apache.hadoop.fs.s3a.Constants.PREFETCH_MAX_BLOCKS_COUNT;
+import static
org.apache.hadoop.fs.statistics.IOStatisticAssertions.verifyStatisticGaugeValue;
+import static
org.apache.hadoop.fs.statistics.StreamStatisticNames.STREAM_READ_BLOCKS_IN_FILE_CACHE;
+import static org.apache.hadoop.io.IOUtils.cleanupWithLogger;
+
+/**
+ * Test the prefetching input stream with LRU cache eviction on
S3ACachingInputStream.
+ */
+@RunWith(Parameterized.class)
+public class ITestS3APrefetchingLruEviction extends AbstractS3ACostTest {
+
+ private final String maxBlocks;
+
+ @Parameterized.Parameters(name = "max-blocks-{0}")
+ public static Collection<Object[]> params() {
+ return Arrays.asList(new Object[][]{
+ {"1"},
+ {"2"},
+ {"3"}
+ });
+ }
Review Comment:
now we test LRU block cache max size: 1, 2, 3 and ensure that results stay
consistent with the size i.e. evictions do take place to maintain the max size
of the cache.
> S3A prefetch - Implement LRU cache for SingleFilePerBlockCache
> --------------------------------------------------------------
>
> Key: HADOOP-18291
> URL: https://issues.apache.org/jira/browse/HADOOP-18291
> Project: Hadoop Common
> Issue Type: Sub-task
> Affects Versions: 3.4.0
> Reporter: Ahmar Suhail
> Assignee: Viraj Jasani
> Priority: Major
> Labels: pull-request-available
>
> Currently there is no limit on the size of disk cache. This means we could
> have a large number of files on files, especially for access patterns that
> are very random and do not always read the block fully.
>
> eg:
> in.seek(5);
> in.read();
> in.seek(blockSize + 10) // block 0 gets saved to disk as it's not fully read
> in.read();
> in.seek(2 * blockSize + 10) // block 1 gets saved to disk
> .. and so on
>
> The in memory cache is bounded, and by default has a limit of 72MB (9
> blocks). When a block is fully read, and a seek is issued it's released
> [here|https://github.com/apache/hadoop/blob/feature-HADOOP-18028-s3a-prefetch/hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/read/S3CachingInputStream.java#L109].
> We can also delete the on disk file for the block here if it exists.
>
> Also maybe add an upper limit on disk space, and delete the file which stores
> data of the block furthest from the current block (similar to the in memory
> cache) when this limit is reached.
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