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Posted to commits@cassandra.apache.org by "Sylvain Lebresne (JIRA)" <ji...@apache.org> on 2012/06/15 20:16:42 UTC
[jira] [Commented] (CASSANDRA-3855) RemoveDeleted dominates
compaction time for large sstable counts
[ https://issues.apache.org/jira/browse/CASSANDRA-3855?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13295818#comment-13295818 ]
Sylvain Lebresne commented on CASSANDRA-3855:
---------------------------------------------
I'll precise that I try to do a quick test to see if I could reproduce "back in the days" but wasn't really able to reproduce something similar to the attached hprof log. I didn't wait up to 100,000,000 keys though.
> RemoveDeleted dominates compaction time for large sstable counts
> ----------------------------------------------------------------
>
> Key: CASSANDRA-3855
> URL: https://issues.apache.org/jira/browse/CASSANDRA-3855
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Affects Versions: 1.1.0
> Reporter: Stu Hood
> Assignee: Yuki Morishita
> Labels: compaction, deletes, leveled
> Attachments: with-cleaning-java.hprof.txt
>
>
> With very large numbers of sstables (2000+ generated by a `bin/stress -n 100,000,000` run with LeveledCompactionStrategy), PrecompactedRow.removeDeletedAndOldShards dominates compaction runtime, such that commenting it out takes compaction throughput from 200KB/s to 12MB/s.
> Stack attached.
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