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https://issues.apache.org/jira/browse/HDFS-2834?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13233535#comment-13233535
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jirapos...@reviews.apache.org commented on HDFS-2834:
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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/4212/
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(Updated 2012-03-20 16:29:56.616292)
Review request for hadoop-hdfs and Todd Lipcon.
Changes
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Review responses
Summary
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New patch for HDFS-2834 (I can't update the old review request).
This addresses bug HDFS-2834.
http://issues.apache.org/jira/browse/HDFS-2834
Diffs (updated)
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hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/BlockReader.java
dfab730
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/BlockReaderLocal.java
cc61697
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java
4187f1c
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java
71c8a50
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/RemoteBlockReader.java
b7da8d4
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/RemoteBlockReader2.java
ea24777
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/BlockReaderTestUtil.java
9d4f4a2
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestBlockReaderLocal.java
PRE-CREATION
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestParallelRead.java
bbd0012
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestShortCircuitLocalRead.java
f4052bb
Diff: https://reviews.apache.org/r/4212/diff
Testing
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Thanks,
Henry
> ByteBuffer-based read API for DFSInputStream
> --------------------------------------------
>
> Key: HDFS-2834
> URL: https://issues.apache.org/jira/browse/HDFS-2834
> Project: Hadoop HDFS
> Issue Type: Improvement
> Reporter: Henry Robinson
> Assignee: Henry Robinson
> Attachments: HDFS-2834-no-common.patch, HDFS-2834.10.patch,
> HDFS-2834.3.patch, HDFS-2834.4.patch, HDFS-2834.5.patch, HDFS-2834.6.patch,
> HDFS-2834.7.patch, HDFS-2834.8.patch, HDFS-2834.9.patch, HDFS-2834.patch,
> HDFS-2834.patch, hdfs-2834-libhdfs-benchmark.png
>
>
> The {{DFSInputStream}} read-path always copies bytes into a JVM-allocated
> {{byte[]}}. Although for many clients this is desired behaviour, in certain
> situations, such as native-reads through libhdfs, this imposes an extra copy
> penalty since the {{byte[]}} needs to be copied out again into a natively
> readable memory area.
> For these cases, it would be preferable to allow the client to supply its own
> buffer, wrapped in a {{ByteBuffer}}, to avoid that final copy overhead.
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