lucene-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Gerrit Jansen van Vuuren (Commented) (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (LUCENE-3653) Lucene Search not scalling
Date Mon, 19 Dec 2011 10:10:31 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-3653?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13172167#comment-13172167
] 

Gerrit Jansen van Vuuren commented on LUCENE-3653:
--------------------------------------------------

Hi Simon,
Thanks, I'll try these on our production systems.
One other change I've made, which I'll submit a patch for (pending testing) is introducing
a ReadonlyRAMFile.

Search for my use case is split into two:
             (1) Search 
             (2) Get Stored data from index.
Now in an in memory index almost zero locking can be achieved.
   All the patches will do great for (1), the ReadonlyRAMFile seems to solve item (2).


                
> 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
>         Attachments: App.java, LUCENE-3653-VirtualMethod+AttributeSource.patch, LUCENE-3653-VirtualMethod+AttributeSource.patch,
LUCENE-3653-VirtualMethod+AttributeSource.patch, LUCENE-3653.patch, 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.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@lucene.apache.org
For additional commands, e-mail: dev-help@lucene.apache.org


Mime
View raw message