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From "Benedict (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-6609) Reduce Bloom Filter Garbage Allocation
Date Mon, 27 Jan 2014 23:12:38 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-6609?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13883496#comment-13883496
] 

Benedict commented on CASSANDRA-6609:
-------------------------------------

bq. so I'm not comfortable touching 1.2

Makes sense

> Reduce Bloom Filter Garbage Allocation
> --------------------------------------
>
>                 Key: CASSANDRA-6609
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6609
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: Benedict
>            Assignee: Benedict
>             Fix For: 2.0.5
>
>         Attachments: tmp.diff, tmp2.patch, tmp3.patch
>
>
> Just spotted that we allocate potentially large amounts of garbage on bloom filter lookups,
since we allocate a new long[] for each hash() and to store the bucket indexes we visit, in
a manner that guarantees they are allocated on heap. With a lot of sstables and many requests,
this could easily be hundreds of megabytes of young gen churn per second.



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