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https://issues.apache.org/jira/browse/HADOOP-10047?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13810463#comment-13810463
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Colin Patrick McCabe commented on HADOOP-10047:
-----------------------------------------------
Looks good. I assume the patch apply failure is something trivial you'll fix
soon.
Thanks for writing some unit tests, too. I see that we're already catching
some bugs in the exception handling of the current code :)
In {{DirectDecompressor#decompress}}, it's interesting that there is both a src
and dst buffer. In the equivalent non-direct-buffer
{{Decompressor#decompress}} function, there is only an output array. Is it
possible to use different 'src' buffers for each call you make to
{{DirectDecompressor#decompress}}? If so, it might be worth documenting this.
If not, I wonder if the src buffer could be supplied to the
{{DirectDecompressionCodec#createDirectDecompressor}} function so that only a
dst buffer needed to be supplied to {{decompress}}?
> Add a directbuffer Decompressor API to hadoop
> ---------------------------------------------
>
> Key: HADOOP-10047
> URL: https://issues.apache.org/jira/browse/HADOOP-10047
> Project: Hadoop Common
> Issue Type: New Feature
> Components: io
> Affects Versions: 2.3.0
> Reporter: Gopal V
> Assignee: Gopal V
> Labels: compression
> Fix For: 2.3.0
>
> Attachments: DirectCompressor.html, DirectDecompressor.html,
> HADOOP-10047-WIP.patch, HADOOP-10047-final.patch,
> HADOOP-10047-redo-WIP.patch, HADOOP-10047-with-tests.patch
>
>
> With the Zero-Copy reads in HDFS (HDFS-5260), it becomes important to perform
> all I/O operations without copying data into byte[] buffers or other buffers
> which wrap over them.
> This is a proposal for adding a DirectDecompressor interface to the
> io.compress, to indicate codecs which want to surface the direct buffer layer
> upwards.
> The implementation should work with direct heap/mmap buffers and cannot
> assume .array() availability.
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