[
https://issues.apache.org/jira/browse/JCR-4057?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15656902#comment-15656902
]
Nils Breunese commented on JCR-4057:
------------------------------------
I have also attached the test case I used to verify that the patch changes the
number of calls performed. It uses Mockito 2.2.12. I'm not sure this is usable
to commit as is, but hopefully helps to illustrate the issue.
> Improve performance of skipping offset nodes for Lucene queries
> ---------------------------------------------------------------
>
> Key: JCR-4057
> URL: https://issues.apache.org/jira/browse/JCR-4057
> Project: Jackrabbit Content Repository
> Issue Type: Improvement
> Components: core
> Affects Versions: 2.10.4
> Reporter: Nils Breunese
> Labels: performance
> Attachments: JCR-4057.patch
>
>
> When doing Lucene-based queries with large offset values like 12000 we see
> pretty bad performance in our system. We have already enabled the
> {{sizeEstimate}} option to improve performance, but still see queries taking
> 6 to 66 seconds.
> We identified the call to {{collectScoreNodes}} in
> {{org.apache.jackrabbit.core.query.lucene.QueryResultImpl#getResults}} to be
> the cause of this. The {{collectScoreNodes}} method builds an anonymous
> {{ArrayList<ScoreNode[]>}} for the offset nodes, which is not used after
> building it, so it uses memory for nothing, and it also does access checks
> for these nodes which are not returned.
> I have attached a patch to Jackrabbit 2.10.4 which just calls {{skip}} on the
> {{MultiColumnQueryHits result}} and using this patch our query times seem to
> stay under 2 seconds.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
