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https://issues.apache.org/jira/browse/LUCENE-3892?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13425246#comment-13425246
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Michael McCandless commented on LUCENE-3892:
--------------------------------------------
OK I think I understand the two patches now.
First, the build.xml changes are noise I think. Second, the patches
both mix in the removal of the current For/PFor postings formats based
on sep (I will separately commit this removal: BlockPF is faster).
Then, one patch (LUCENE-3892-blockFor&hardcode(base).patch) keeps
using the separate packed-ints impl we have, but cuts over to
LongBuffer instead of int[] for the decoded values (still uses
IntBuffer for the encoded values), while the other patch
(LUCENE-3892-blockFor&packedecoder(comp).patch) uses oal.util.packed
and LongBuffer for both encoded and decoded values.
So it's nice to see that "merely" switching to LongBuffer to pass
encoded/decoded values around doesn't seem to hurt much, except for
And queries (odd?), but then switching to oal.util.packed does hurt
(also odd because our packed ints impl has been heavily optimized
lately).
> Add a useful intblock postings format (eg, FOR, PFOR, PFORDelta,
> Simple9/16/64, etc.)
> -------------------------------------------------------------------------------------
>
> Key: LUCENE-3892
> URL: https://issues.apache.org/jira/browse/LUCENE-3892
> Project: Lucene - Core
> Issue Type: Improvement
> Reporter: Michael McCandless
> Labels: gsoc2012, lucene-gsoc-12
> Fix For: 4.1
>
> Attachments: LUCENE-3892-BlockTermScorer.patch,
> LUCENE-3892-blockFor&hardcode(base).patch,
> LUCENE-3892-blockFor&packedecoder(comp).patch,
> LUCENE-3892-blockFor-with-packedints-decoder.patch,
> LUCENE-3892-blockFor-with-packedints-decoder.patch,
> LUCENE-3892-blockFor-with-packedints.patch,
> LUCENE-3892-direct-IntBuffer.patch, LUCENE-3892-for&pfor-with-javadoc.patch,
> LUCENE-3892-handle_open_files.patch,
> LUCENE-3892-pfor-compress-iterate-numbits.patch,
> LUCENE-3892-pfor-compress-slow-estimate.patch, LUCENE-3892_for_byte[].patch,
> LUCENE-3892_for_int[].patch, LUCENE-3892_for_unfold_method.patch,
> LUCENE-3892_pfor_unfold_method.patch, LUCENE-3892_pulsing_support.patch,
> LUCENE-3892_settings.patch, LUCENE-3892_settings.patch
>
>
> On the flex branch we explored a number of possible intblock
> encodings, but for whatever reason never brought them to completion.
> There are still a number of issues opened with patches in different
> states.
> Initial results (based on prototype) were excellent (see
> http://blog.mikemccandless.com/2010/08/lucene-performance-with-pfordelta-codec.html
> ).
> I think this would make a good GSoC project.
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