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https://issues.apache.org/jira/browse/LUCENE-1410?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12804127#action_12804127
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Paul Elschot commented on LUCENE-1410:
--------------------------------------

Zhang, 2008, see above, reports this:
{quote}
The poor speed of variable- byte on position data is primarily due
to the fact that position values are larger and more often require
2 bytes under variable-byte; this case tends to be much slower due
to a branch mispredict.
{quote}

Taking another look at the position data above (3 October 2008) 11.6% of prx 
values take 7 bits or less,
and the rest fits in 15 bits. So why not encode the position data as VShort (1 
bit as in VByte and 15 bits data) ?
That would enlarge a typical prx file by about 6% and increase position 
decoding speed a lot,
probably about 3 times (see Table 1 in the same paper).

> PFOR implementation
> -------------------
>
>                 Key: LUCENE-1410
>                 URL: https://issues.apache.org/jira/browse/LUCENE-1410
>             Project: Lucene - Java
>          Issue Type: New Feature
>          Components: Other
>            Reporter: Paul Elschot
>            Priority: Minor
>         Attachments: autogen.tgz, LUCENE-1410-codecs.tar.bz2, 
> LUCENE-1410b.patch, LUCENE-1410c.patch, LUCENE-1410d.patch, 
> LUCENE-1410e.patch, TermQueryTests.tgz, TestPFor2.java, TestPFor2.java, 
> TestPFor2.java
>
>   Original Estimate: 21840h
>  Remaining Estimate: 21840h
>
> Implementation of Patched Frame of Reference.

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