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Date: Tue, 19 Mar 2013 21:27:16 +0000 (UTC)
From: "stack (JIRA)" <jira@apache.org>
To: issues@hbase.apache.org
Message-ID: <JIRA.12632310.1360801298824.14750.1363728436270@arcas>
In-Reply-To: <JIRA.12632310.1360801298824@arcas>
References: <JIRA.12632310.1360801298824@arcas>
Subject: [jira] [Commented] (HBASE-7842) Add compaction policy that explores
 more storefile groups
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    [ https://issues.apache.org/jira/browse/HBASE-7842?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13606849#comment-13606849 ] 

stack commented on HBASE-7842:
------------------------------

[~eclark] See [~sershe]'s note above.
                
> Add compaction policy that explores more storefile groups
> ---------------------------------------------------------
>
>                 Key: HBASE-7842
>                 URL: https://issues.apache.org/jira/browse/HBASE-7842
>             Project: HBase
>          Issue Type: New Feature
>          Components: Compaction
>            Reporter: Elliott Clark
>            Assignee: Elliott Clark
>         Attachments: HBASE-7842-0.patch, HBASE-7842-2.patch, HBASE-7842-3.patch, HBASE-7842-4.patch
>
>
> Some workloads that are not as stable can have compactions that are too large or too small using the current storefile selection algorithm.
> Currently:
> * Find the first file that Size(fi) <= Sum(0, i-1, FileSize(fx))
> * Ensure that there are the min number of files (if there aren't then bail out)
> * If there are too many files keep the larger ones.
> I would propose something like:
> * Find all sets of storefiles where every file satisfies 
> ** FileSize(fi) <= Sum(0, i-1, FileSize(fx))
> ** Num files in set =< max
> ** Num Files in set >= min
> * Then pick the set of files that maximizes ((# storefiles in set) / Sum(FileSize(fx)))
> The thinking is that the above algorithm is pretty easy reason about, all files satisfy the ratio, and should rewrite the least amount of data to get the biggest impact in seeks.

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