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https://issues.apache.org/jira/browse/JCR-2025?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12683875#action_12683875
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Marcel Reutegger commented on JCR-2025:
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Committed missing class JackrabbitTermQuery in revision: 756445
> Optimize concurrent queries
> ---------------------------
>
> Key: JCR-2025
> URL: https://issues.apache.org/jira/browse/JCR-2025
> Project: Jackrabbit Content Repository
> Issue Type: Improvement
> Components: jackrabbit-core
> Reporter: Marcel Reutegger
> Priority: Minor
> Fix For: core-1.4.10, 1.6.0
>
> Attachments: JCR-2025.patch
>
>
> There are a number of bottlenecks that prevent scalability of concurrent
> queries:
> - Fake norms are created repeatedly because a new
> SearchIndex$CombinedIndexReader is created for each query. This prevents
> caching of fake norms on the level of the CombinedIndexReader. Creating fake
> norms for index readers that span multiple sub reader is inefficient and
> should be avoided. Like with other Jackrabbit specific queries, there should
> be one for TermQuery, which is aware of sub readers. Its weight should then
> create one scorer for each sub reader. This effectively reuses the fake norms
> on the sub reader.
> - There should be a UUID cache that maps document number to UUID. This is
> basically the inverse of the existing DocNumberCache. UUID lookup is
> regularly a bottleneck in the SegmentReader where the method document() is
> synchronized and does I/O.
> - Queries often contain constraints that limit the result to nodes with a
> certain flag set to a literal. These constraints should be cached in the
> query handler.
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