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Date: Tue, 31 Jan 2012 00:05:12 +0000 (UTC)
From: "dhruba borthakur (Created) (JIRA)" <jira@apache.org>
To: issues@hbase.apache.org
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Subject: [jira] [Created] (HBASE-5303) Separate out rows into multiple files
 during compaction for better block cache utilization
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Separate out rows into multiple files during compaction for better block cache utilization
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                 Key: HBASE-5303
                 URL: https://issues.apache.org/jira/browse/HBASE-5303
             Project: HBase
          Issue Type: Improvement
          Components: regionserver
            Reporter: dhruba borthakur
            Assignee: dhruba borthakur


This seems odd at first sight, a compaction is supposed to reduce the number of files. But there is great advantage to creating hbase blocks where adjacent keys are accessed together. One approach would be to make compaction write out hot-rows into one file and the cold-rows into another file. This increases the efficiency of the block cache because only the blocks in the hot-rows file will most frequently be populated in the block cache.

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