[jira] [Closed] (JCR-4057) Improve performance of skipping offset nodes for Lucene queries

["Julian Reschke (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/JCR-4057?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Julian Reschke closed JCR-4057.
-------------------------------

> 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
>            Priority: Major
>              Labels: performance
>         Attachments: JCR-4057-test.patch, JCR-4057.patch
>
>
> When doing Lucene-based queries with large offset values like 12000 I see pretty bad performance in our system. I have already enabled the {{sizeEstimate}} option to improve performance, but still see queries taking 6 to 66 seconds.
> I have identified the call to {{collectScoreNodes}} for offset nodes 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.



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