[
https://issues.apache.org/jira/browse/LUCENE-2531?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12887126#action_12887126
]
Michael McCandless commented on LUCENE-2531:
--------------------------------------------
I hear you; this stuff is kinda hairy ;)
The usage of reverse (and, sortPos) was only in dead code, inside the convert
method.
The convert method used to be used more often (to do on-demand convert of the
ord when its readerGen != current one), but we stopped doing that and only
convert the bottom slot now, which mean this if:
{noformat}
if (sortPos == 0 && bottomSlot != -1 && bottomSlot != slot) {
{noformat}
Can never be true (bottomSlot is *always* == slot), so that true clause was all
dead code anyway.
> FieldComparator.TermOrdValComparator compares by value unnecessarily
> --------------------------------------------------------------------
>
> Key: LUCENE-2531
> URL: https://issues.apache.org/jira/browse/LUCENE-2531
> Project: Lucene - Java
> Issue Type: Improvement
> Components: Search
> Reporter: Michael McCandless
> Priority: Minor
> Fix For: 3.1, 4.0
>
> Attachments: LUCENE-2504-3x.patch, LUCENE-2504.patch,
> LUCENE-2531-3x.patch, LUCENE-2531.patch
>
>
> Digging on LUCENE-2504, I noticed that TermOrdValComparator's compareBottom
> method falls back on compare-by-value when it needn't.
> Specifically, if we know the current bottom ord "matches" the current
> segment, we can skip the value comparison when the ords are the same (ie,
> return 0) because the ords are exactly comparable.
> This is hurting string sort perf especially for optimized indices (and also
> unoptimized indices), and especially for highly redundant (not many unique
> values) fields. This affects all releases >= 2.9.x, but trunk is likely more
> severely affected since looking up a value is more costly.
--
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]
