[
https://issues.apache.org/jira/browse/LUCENE-502?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Robert Muir resolved LUCENE-502.
--------------------------------
Resolution: Fixed
Fix Version/s: 4.0
In trunk, there is no longer a score cache in TermScorer because this is just
an optimization for the TF/IDF scoring formula.
Instead this optimization is in TFIDFSimilarity, if you want or don't want
similar pre-computations in your scoring you can adjust this by plugging in
your own Similarity.
> TermScorer caches values unnecessarily
> --------------------------------------
>
> Key: LUCENE-502
> URL: https://issues.apache.org/jira/browse/LUCENE-502
> Project: Lucene - Java
> Issue Type: Improvement
> Components: core/search
> Affects Versions: 1.9
> Reporter: Steven Tamm
> Priority: Minor
> Fix For: 4.0
>
> Attachments: LUCENE-502.patch, TermScorer.patch
>
>
> TermScorer aggressively caches the doc and freq of 32 documents at a time for
> each term scored. When querying for a lot of terms, this causes a lot of
> garbage to be created that's unnecessary. The SegmentTermDocs from which it
> retrieves its information doesn't have any optimizations for bulk loading,
> and it's unnecessary.
> In addition, it has a SCORE_CACHE, that's of limited benefit. It's caching
> the result of a sqrt that should be placed in DefaultSimilarity, and if
> you're only scoring a few documents that contain those terms, there's no need
> to precalculate the SQRT, especially on modern VMs.
> Enclosed is a patch that replaces TermScorer with a version that does not
> cache the docs or feqs. In the case of a lot of queries, that saves 196
> bytes/term, the unnecessary disk IO, and extra SQRTs which adds up.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
