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https://issues.apache.org/jira/browse/CASSANDRA-11623?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15257797#comment-15257797
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Marcus Eriksson commented on CASSANDRA-11623:
---------------------------------------------
No particular reason other than all patches are risks. If the performance
improvement is big it should go into 2.2 though
Do you have any numbers in your cluster?
> Compactions w/ Short Rows Spending Time in getOnDiskFilePointer
> ---------------------------------------------------------------
>
> Key: CASSANDRA-11623
> URL: https://issues.apache.org/jira/browse/CASSANDRA-11623
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Tom Petracca
> Assignee: Tom Petracca
> Priority: Minor
> Fix For: 3.x
>
> Attachments: compactiontask_profile.png
>
>
> Been doing some performance tuning and profiling of my cassandra cluster and
> noticed that compaction speeds for my tables that I know to have very short
> rows were going particularly slowly. Profiling shows a ton of time being
> spent in BigTableWriter.getOnDiskFilePointer(), and attaching strace to a
> CompactionTask shows that a majority of time is being spent lseek (called by
> getOnDiskFilePointer), and not read or write.
> Going deeper it looks like we call getOnDiskFilePointer each row (sometimes
> multiple times per row) in order to see if we've reached our expected sstable
> size and should start a new writer. This is pretty unnecessary.
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