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Posted to dev@lucene.apache.org by "Simon Willnauer (Assigned) (JIRA)" <ji...@apache.org> on 2011/12/22 13:38:31 UTC
[jira] [Assigned] (LUCENE-3653) Lucene Search not scalling
[ https://issues.apache.org/jira/browse/LUCENE-3653?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Simon Willnauer reassigned LUCENE-3653:
---------------------------------------
Assignee: Simon Willnauer
> Lucene Search not scalling
> --------------------------
>
> Key: LUCENE-3653
> URL: https://issues.apache.org/jira/browse/LUCENE-3653
> Project: Lucene - Java
> Issue Type: Improvement
> Reporter: Gerrit Jansen van Vuuren
> Assignee: Simon Willnauer
> Fix For: 3.6, 4.0
>
> Attachments: App.java, LUCENE-3653-VirtualMethod+AttributeSource.patch, LUCENE-3653-VirtualMethod+AttributeSource.patch, LUCENE-3653-VirtualMethod+AttributeSource.patch, LUCENE-3653-no-sync.png, LUCENE-3653-sync-.png, LUCENE-3653.patch, LUCENE-3653.patch, LUCENE-3653.patch-BiasedLockingStartupDelay_1.png, LUCENE-3653.patch-BiasedLockingStartupDelay_2.png, LUCENE-3653.patch-BiasedLockingStartupDelay_3.png, Threads-LUCENE-3653.patch.png, lucene-unsync.diff, profile_1_a.png, profile_1_b.png, profile_1_c.png, profile_1_d.png, profile_2_a.png, profile_2_b.png, profile_2_c.png
>
>
> I've noticed that when doing thousands of searches in a single thread the average time is quite low i.e. a few milliseconds. When adding more concurrent searches doing exactly the same search the average time increases drastically.
> I've profiled the search classes and found that the whole of lucene blocks on
> org.apache.lucene.index.SegmentCoreReaders.getTermsReader
> org.apache.lucene.util.VirtualMethod
> public synchronized int getImplementationDistance
> org.apache.lucene.util.AttributeSourcew.getAttributeInterfaces
> These cause search times to increase from a few milliseconds to up to 2 seconds when doing 500 concurrent searches on the same in memory index. Note: That the index is not being updates at all, so not refresh methods are called at any stage.
> Some questions:
> Why do we need synchronization here?
> There must be a non-lockable solution for these, they basically cause lucene to be ok for single thread applications but disastrous for any concurrent implementation.
> I'll do some experiments by removing the synchronization from the methods of these classes.
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