[jira] [Resolved] (HBASE-14867) SimpleRegionNormalizer needs to have better heuristics to trigger merge operation

["Ted Yu (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HBASE-14867?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Ted Yu resolved HBASE-14867.
----------------------------
    Resolution: Fixed

Created HBASE-15065 to address Enis' comments

> SimpleRegionNormalizer needs to have better heuristics to trigger merge operation
> ---------------------------------------------------------------------------------
>
>                 Key: HBASE-14867
>                 URL: https://issues.apache.org/jira/browse/HBASE-14867
>             Project: HBase
>          Issue Type: Bug
>          Components: master
>    Affects Versions: 1.2.0
>            Reporter: Romil Choksi
>            Assignee: Ted Yu
>             Fix For: 2.0.0, 1.2.0, 1.3.0
>
>         Attachments: 14867-v2.txt, 14867-v3.txt, 14867-v4.txt
>
>
> SimpleRegionNormalizer needs to have better heuristics to trigger merge operation. SimpleRegionNormalizer is not able to trigger a merge action if the table's smallest region has neighboring regions that are larger than table's average region size, whereas there are other smaller regions whose combined size is less than the average region size. 
> For example, 
> - Consider a table with six region, say r1 to r6. 
> - Keep r1 as empty and create some data say, 100K rows of data for each of the regions r2, r3 and r4. Create smaller amount of data for regions r5 and r6, say about 27K rows of data.
> - Run the normalizer. Verify the number the regions for that table and also check the master log to see if any merge action was triggered as a result of normalization. 
> In such scenario, it would be better to have a merge action triggered for those two smaller regions r5 and r6 even though either of them is not the smallest one



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