[ http://issues.apache.org/jira/browse/HADOOP-54?page=all ]
Arun C Murthy updated HADOOP-54:
--------------------------------
Attachment: SequenceFiles.patch
Here's the patch for block compressed SequenceFiles.
Main attractions:
a) Three different writers for SequenceFiles: Writer, RecordCompressWriter,
BlockCompressWriter (with a factory to create the different writers).
b) The 'raw' apis are significantly different (as per previous discussions here)
c) Fixed SequenceFile.Sorter to take advantage of new 'raw' apis and some minor
tweak/enhancements there.
As per Owen's suggestion, I've only uploaded the patch... once I get some
feedback, I'll go ahead and change the 'status' to 'Patch Available'.
> SequenceFile should compress blocks, not individual entries
> -----------------------------------------------------------
>
> Key: HADOOP-54
> URL: http://issues.apache.org/jira/browse/HADOOP-54
> Project: Hadoop
> Issue Type: Improvement
> Components: io
> Affects Versions: 0.2.0
> Reporter: Doug Cutting
> Assigned To: Arun C Murthy
> Fix For: 0.6.0
>
> Attachments: SequenceFiles.patch, VIntCompressionResults.txt
>
>
> SequenceFile will optionally compress individual values. But both
> compression and performance would be much better if sequences of keys and
> values are compressed together. Sync marks should only be placed between
> blocks. This will require some changes to MapFile too, so that all file
> positions stored there are the positions of blocks, not entries within
> blocks. Probably this can be accomplished by adding a
> getBlockStartPosition() method to SequenceFile.Writer.
--
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators:
http://issues.apache.org/jira/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira
