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https://issues.apache.org/jira/browse/LUCENE-3892?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13398507#comment-13398507
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Han Jiang edited comment on LUCENE-3892 at 6/21/12 3:53 PM:
------------------------------------------------------------

For decompressing phase, replace the use of IntBuffer with a direct int[] to 
int[] decoder. Method convert() is supposed to be performant enough...coz it is 
not different from the inner implementation of IntBuffer.get(), 
i.e.http://massapi.com/source/jdk1.6.0_17/src/java/nio/Bits.java.html, line 
193. However, result isn't interesting.

Hmm, there is an extra block of memory write here, which Mike wanted to avoid 
in previous patch. That should be the cause.
                
      was (Author: billy):
    for decompressing phase, replace the use of IntBuffer with a direct int[] 
to int[] decoder. Method convert() is supposed to be performant enough...coz it 
is not different from the inner implementation of IntBuffer.get(), 
i.e.http://massapi.com/source/jdk1.6.0_17/src/java/nio/Bits.java.html, line 
193. However, result isn't interesting.
                  
> 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 - Java
>          Issue Type: Improvement
>            Reporter: Michael McCandless
>              Labels: gsoc2012, lucene-gsoc-12
>             Fix For: 4.1
>
>         Attachments: LUCENE-3892-direct-IntBuffer.patch, 
> LUCENE-3892_for.patch, LUCENE-3892_for_int[].patch, 
> LUCENE-3892_for_unfold_method.patch, LUCENE-3892_pfor.patch, 
> LUCENE-3892_pfor.patch, LUCENE-3892_pfor.patch, 
> LUCENE-3892_pfor_unfold_method.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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