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https://issues.apache.org/jira/browse/HDFS-2834?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13233524#comment-13233524
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jirapos...@reviews.apache.org commented on HDFS-2834:
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bq. On 2012-03-20 01:27:50, Todd Lipcon wrote:
bq. >
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestBlockReaderLocal.java,
line 44
bq. > <https://reviews.apache.org/r/4212/diff/2/?file=90213#file90213line44>
bq. >
bq. > shouldn't this be true?
Oops, yes. Thankfully the test still passes when it's testing the right path...
bq. On 2012-03-20 01:27:50, Todd Lipcon wrote:
bq. >
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestBlockReaderLocal.java,
lines 81-82
bq. > <https://reviews.apache.org/r/4212/diff/2/?file=90213#file90213line81>
bq. >
bq. > no reason to use DFSClient here. Instead you can just use the
filesystem, right? Then downcast the stream you get back?
Good point - no need even to downcast since FSDataInputStream has the API.
bq. On 2012-03-20 01:27:50, Todd Lipcon wrote:
bq. >
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestBlockReaderLocal.java,
line 104
bq. > <https://reviews.apache.org/r/4212/diff/2/?file=90213#file90213line104>
bq. >
bq. > don't you want an assert on sawException here? You can also use
GenericTestUtils.assertExceptionContains() if you want to check the text of it
Good catch. No particular need to assert the content of the exception - any
checksum error is good enough here.
bq. On 2012-03-20 01:27:50, Todd Lipcon wrote:
bq. >
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/BlockReaderLocal.java,
lines 562-564
bq. > <https://reviews.apache.org/r/4212/diff/2/?file=90207#file90207line562>
bq. >
bq. > this comment seems like it's in the wrong spot, since the code that
comes after it doesn't reference offsetFromChunkBoundary.
I removed the comment, it's covered by the comment at line 549.
- Henry
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This is an automatically generated e-mail. To reply, visit:
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-----------------------------------------------------------
On 2012-03-09 00:47:24, Henry Robinson wrote:
bq.
bq. -----------------------------------------------------------
bq. This is an automatically generated e-mail. To reply, visit:
bq. https://reviews.apache.org/r/4212/
bq. -----------------------------------------------------------
bq.
bq. (Updated 2012-03-09 00:47:24)
bq.
bq.
bq. Review request for hadoop-hdfs and Todd Lipcon.
bq.
bq.
bq. Summary
bq. -------
bq.
bq. New patch for HDFS-2834 (I can't update the old review request).
bq.
bq.
bq. This addresses bug HDFS-2834.
bq. http://issues.apache.org/jira/browse/HDFS-2834
bq.
bq.
bq. Diffs
bq. -----
bq.
bq.
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/BlockReader.java
dfab730
bq.
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/BlockReaderLocal.java
cc61697
bq.
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java
4187f1c
bq.
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java
2b817ff
bq.
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/RemoteBlockReader.java
b7da8d4
bq.
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/RemoteBlockReader2.java
ea24777
bq.
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/BlockReaderTestUtil.java
9d4f4a2
bq.
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestBlockReaderLocal.java
PRE-CREATION
bq.
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestParallelRead.java
bbd0012
bq.
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestShortCircuitLocalRead.java
eb2a1d8
bq.
bq. Diff: https://reviews.apache.org/r/4212/diff
bq.
bq.
bq. Testing
bq. -------
bq.
bq.
bq. Thanks,
bq.
bq. Henry
bq.
bq.
> 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-2834.3.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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