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Posted to commits@cassandra.apache.org by "Jonathan Ellis (JIRA)" <ji...@apache.org> on 2010/02/21 22:49:27 UTC

[jira] Created: (CASSANDRA-814) Compaction bucketizing is computing average size incorrectly

Compaction bucketizing is computing average size incorrectly
------------------------------------------------------------

                 Key: CASSANDRA-814
                 URL: https://issues.apache.org/jira/browse/CASSANDRA-814
             Project: Cassandra
          Issue Type: Bug
          Components: Core
    Affects Versions: 0.5
            Reporter: Jonathan Ellis
            Assignee: Jonathan Ellis
            Priority: Minor
             Fix For: 0.6


in the worst case (which doesn't seem to actually affect anyone) this could prevent sstables from being compacted, incorrectly

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[jira] Commented: (CASSANDRA-814) Compaction bucketizing is computing average size incorrectly

Posted by "Stu Hood (JIRA)" <ji...@apache.org>.
    [ https://issues.apache.org/jira/browse/CASSANDRA-814?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12837482#action_12837482 ] 

Stu Hood commented on CASSANDRA-814:
------------------------------------

+1

> Compaction bucketizing is computing average size incorrectly
> ------------------------------------------------------------
>
>                 Key: CASSANDRA-814
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-814
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 0.5
>            Reporter: Jonathan Ellis
>            Assignee: Jonathan Ellis
>            Priority: Minor
>             Fix For: 0.6
>
>         Attachments: 0001-rename-CM.getCompactionBuckets-CM.getBuckets.txt, 0002-fix-average-size-calculation.txt
>
>
> in the worst case (which doesn't seem to actually affect anyone) this could prevent sstables from being compacted, incorrectly

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[jira] Updated: (CASSANDRA-814) Compaction bucketizing is computing average size incorrectly

Posted by "Jonathan Ellis (JIRA)" <ji...@apache.org>.
     [ https://issues.apache.org/jira/browse/CASSANDRA-814?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jonathan Ellis updated CASSANDRA-814:
-------------------------------------

    Attachment:     (was: 0001-rename-CM.getCompactionBuckets-CM.getBuckets.txt)

> Compaction bucketizing is computing average size incorrectly
> ------------------------------------------------------------
>
>                 Key: CASSANDRA-814
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-814
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 0.5
>            Reporter: Jonathan Ellis
>            Assignee: Jonathan Ellis
>            Priority: Minor
>             Fix For: 0.6
>
>
> in the worst case (which doesn't seem to actually affect anyone) this could prevent sstables from being compacted, incorrectly

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[jira] Commented: (CASSANDRA-814) Compaction bucketizing is computing average size incorrectly

Posted by "Stu Hood (JIRA)" <ji...@apache.org>.
    [ https://issues.apache.org/jira/browse/CASSANDRA-814?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12837466#action_12837466 ] 

Stu Hood commented on CASSANDRA-814:
------------------------------------

This doesn't look right...

 * We use < and > in the if statement for existing buckets, which means that an SSTable of exactly half the average or exactly 1.5 the average will create a new bucket.
 * We always divide by 2 to calculate the average, although there will typically be more than 2 sstables in a bucket.

> Compaction bucketizing is computing average size incorrectly
> ------------------------------------------------------------
>
>                 Key: CASSANDRA-814
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-814
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 0.5
>            Reporter: Jonathan Ellis
>            Assignee: Jonathan Ellis
>            Priority: Minor
>             Fix For: 0.6
>
>         Attachments: 0001-rename-CM.getCompactionBuckets-CM.getBuckets.txt, 0002-fix-average-size-calculation.txt
>
>
> in the worst case (which doesn't seem to actually affect anyone) this could prevent sstables from being compacted, incorrectly

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[jira] Updated: (CASSANDRA-814) Compaction bucketizing is computing average size incorrectly

Posted by "Jonathan Ellis (JIRA)" <ji...@apache.org>.
     [ https://issues.apache.org/jira/browse/CASSANDRA-814?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jonathan Ellis updated CASSANDRA-814:
-------------------------------------

    Attachment:     (was: 0002-fix-average-size-calculation.txt)

> Compaction bucketizing is computing average size incorrectly
> ------------------------------------------------------------
>
>                 Key: CASSANDRA-814
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-814
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 0.5
>            Reporter: Jonathan Ellis
>            Assignee: Jonathan Ellis
>            Priority: Minor
>             Fix For: 0.6
>
>
> in the worst case (which doesn't seem to actually affect anyone) this could prevent sstables from being compacted, incorrectly

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You can reply to this email to add a comment to the issue online.


[jira] Updated: (CASSANDRA-814) Compaction bucketizing is computing average size incorrectly

Posted by "Jonathan Ellis (JIRA)" <ji...@apache.org>.
     [ https://issues.apache.org/jira/browse/CASSANDRA-814?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jonathan Ellis updated CASSANDRA-814:
-------------------------------------

    Attachment: 0002-fix-average-size-calculation.txt
                0001-rename-CM.getCompactionBuckets-CM.getBuckets.txt

> Compaction bucketizing is computing average size incorrectly
> ------------------------------------------------------------
>
>                 Key: CASSANDRA-814
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-814
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 0.5
>            Reporter: Jonathan Ellis
>            Assignee: Jonathan Ellis
>            Priority: Minor
>             Fix For: 0.6
>
>         Attachments: 0001-rename-CM.getCompactionBuckets-CM.getBuckets.txt, 0002-fix-average-size-calculation.txt
>
>
> in the worst case (which doesn't seem to actually affect anyone) this could prevent sstables from being compacted, incorrectly

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You can reply to this email to add a comment to the issue online.


[jira] Commented: (CASSANDRA-814) Compaction bucketizing is computing average size incorrectly

Posted by "Jonathan Ellis (JIRA)" <ji...@apache.org>.
    [ https://issues.apache.org/jira/browse/CASSANDRA-814?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12837473#action_12837473 ] 

Jonathan Ellis commented on CASSANDRA-814:
------------------------------------------

> We use < and > in the if statement

doesn't seem that inclusive comparisons is necessarily any more correct, really.

> We always divide by 2

good catch, fixed in new patchset.

> Compaction bucketizing is computing average size incorrectly
> ------------------------------------------------------------
>
>                 Key: CASSANDRA-814
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-814
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 0.5
>            Reporter: Jonathan Ellis
>            Assignee: Jonathan Ellis
>            Priority: Minor
>             Fix For: 0.6
>
>         Attachments: 0001-rename-CM.getCompactionBuckets-CM.getBuckets.txt, 0002-fix-average-size-calculation.txt
>
>
> in the worst case (which doesn't seem to actually affect anyone) this could prevent sstables from being compacted, incorrectly

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You can reply to this email to add a comment to the issue online.


[jira] Updated: (CASSANDRA-814) Compaction bucketizing is computing average size incorrectly

Posted by "Jonathan Ellis (JIRA)" <ji...@apache.org>.
     [ https://issues.apache.org/jira/browse/CASSANDRA-814?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jonathan Ellis updated CASSANDRA-814:
-------------------------------------

    Attachment: 0002-fix-average-size-calculation.txt
                0001-rename-CM.getCompactionBuckets-CM.getBuckets.txt

> Compaction bucketizing is computing average size incorrectly
> ------------------------------------------------------------
>
>                 Key: CASSANDRA-814
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-814
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 0.5
>            Reporter: Jonathan Ellis
>            Assignee: Jonathan Ellis
>            Priority: Minor
>             Fix For: 0.6
>
>         Attachments: 0001-rename-CM.getCompactionBuckets-CM.getBuckets.txt, 0002-fix-average-size-calculation.txt
>
>
> in the worst case (which doesn't seem to actually affect anyone) this could prevent sstables from being compacted, incorrectly

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You can reply to this email to add a comment to the issue online.