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Posted to dev@parquet.apache.org by "Julien Le Dem (JIRA)" <ji...@apache.org> on 2016/08/01 21:41:20 UTC
[jira] [Commented] (PARQUET-671) Improve performance of
RLE/bit-packed decoding in parquet-cpp
[ https://issues.apache.org/jira/browse/PARQUET-671?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15402877#comment-15402877 ]
Julien Le Dem commented on PARQUET-671:
---------------------------------------
Thanks [~edaniel]
Looking forward to see your PR
> Improve performance of RLE/bit-packed decoding in parquet-cpp
> -------------------------------------------------------------
>
> Key: PARQUET-671
> URL: https://issues.apache.org/jira/browse/PARQUET-671
> Project: Parquet
> Issue Type: Improvement
> Components: parquet-cpp
> Reporter: Eric Daniel
> Assignee: Eric Daniel
>
> There are steps that can dramatically improve decoding performance:
> - when decoding repeated values in the rle/dictionary encoding, do the dictionary lookup only once
> - when decoding bit-packed sequences, do the decoding in batches so the bit unpacker's state can be kept in registers (instead of updating members for every decoded value)
> - use Daniel Lemire's fast unpacking routines whenever possible (https://github.com/lemire/FrameOfReference/)
> I have a PR ready to implement these changes.
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