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Posted to commits@cassandra.apache.org by "Yuki Morishita (JIRA)" <ji...@apache.org> on 2012/07/20 17:25:35 UTC

[jira] [Updated] (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:all-tabpanel ]

Yuki Morishita updated CASSANDRA-3855:
--------------------------------------

    Attachment: 3855.txt

So I summarized and attached patch. Tested on trunk and confirmed it fixed.
                
> 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: 3855.txt, 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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