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https://issues.apache.org/jira/browse/CASSANDRA-4860?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ryan McGuire reopened CASSANDRA-4860:
-------------------------------------
Tester: enigmacurry
I've been working on a 2.0/1.2 read performance regression analysis ([report is
here|http://goo.gl/KHZfL]) and it brought me back to this ticket.
The patch as it was applied in revision
94fa82558f198489e0eefb0c14392607d5d23224 introduces a read performance penalty
of about ~20%.
I've tested reverting this patch and applying on top of the latest 2.0 branch
and it greatly improves right performance.
I don't claim to know what this patch really does, so not sure if that's an
appropriate action to take or not, but I've attached my patch here regardless
(trunk-4860-revert.patch).
> Estimated Row Cache Entry size incorrect (always 24?)
> -----------------------------------------------------
>
> Key: CASSANDRA-4860
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4860
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Affects Versions: 1.1.0
> Reporter: Chris Burroughs
> Assignee: Vijay
> Fix For: 1.2.0 beta 3
>
> Attachments: 0001-CASSANDRA-4860-for-11.patch,
> 0001-CASSANDRA-4860.patch, trunk-4860-revert.patch
>
>
> After running for several hours the RowCacheSize was suspicious low (ie 70
> something MB) I used CASSANDRA-4859 to measure the size and number of
> entries on a node:
> In [3]: 1560504./65021
> Out[3]: 24.0
> In [4]: 2149464./89561
> Out[4]: 24.0
> In [6]: 7216096./300785
> Out[6]: 23.990877204647838
> That's RowCacheSize/RowCacheNumEntires . Just to prove I don't have crazy
> small rows the mean size of the row *keys* in the saved cache is 67 and
> Compacted row mean size: 355. No jamm errors in the log
> Config notes:
> row_cache_provider: ConcurrentLinkedHashCacheProvider
> row_cache_size_in_mb: 2048
> Version info:
> * C*: 1.1.6
> * centos 2.6.32-220.13.1.el6.x86_64
> * java 6u31 Java HotSpot(TM) 64-Bit Server VM (build 20.6-b01, mixed mode)
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