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Ryan McGuire edited comment on CASSANDRA-4860 at 3/28/13 4:58 AM: ------------------------------------------------------------------ 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 read 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). was (Author: 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) -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira