Speed up Lucene's low level bulk postings read API
--------------------------------------------------
Key: LUCENE-2723
URL: https://issues.apache.org/jira/browse/LUCENE-2723
Project: Lucene - Java
Issue Type: Improvement
Components: Index
Reporter: Michael McCandless
Assignee: Michael McCandless
Fix For: 4.0
Spinoff from LUCENE-1410.
The flex DocsEnum has a simple bulk-read API that reads the next chunk
of docs/freqs. But it's a poor fit for intblock codecs like FOR/PFOR
(from LUCENE-1410). This is not unlike sucking coffee through those
tiny plastic coffee stirrers they hand out airplanes that,
surprisingly, also happen to function as a straw.
As a result we see no perf gain from using FOR/PFOR.
I had hacked up a fix for this, described at in my blog post at
http://chbits.blogspot.com/2010/08/lucene-performance-with-pfordelta-codec.html
I'm opening this issue to get that work to a committable point.
So... I've worked out a new bulk-read API to address performance
bottleneck. It has some big changes over the current bulk-read API:
* You can now also bulk-read positions (but not payloads), but, I
have yet to cutover positional queries.
* The buffer contains doc deltas, not absolute values, for docIDs
and positions (freqs are absolute).
* Deleted docs are not filtered out.
* The doc & freq buffers need not be "aligned". For fixed intblock
codecs (FOR/PFOR) they will be, but for varint codecs (Simple9/16,
Group varint, etc.) they won't be.
It's still a work in progress...
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
