[jira] [Commented] (HBASE-22285) A normalizer which merges very small size regions with adjacent regions.(MergeToNormalize)

["Aman Poonia (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-22285?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16860663#comment-16860663 ] 

Aman Poonia commented on HBASE-22285:
-------------------------------------

okay. Timestamp thing will not work.

If a table has been pre-split and we don't want normalizer to do anything ideally we should not enable normalizer on such table. By default normalizer is disabled on all tables. Only when we enable this property(NORMALIZATION_ENABLED) on a table normalizer will pick it.

This will keep things simple. If user feels that this table is not normalized(after it was pre-split) and it needs to be then table property can be changed and normalizer will do its job for the table.

> A normalizer which merges very small size regions with adjacent regions.(MergeToNormalize)
> ------------------------------------------------------------------------------------------
>
>                 Key: HBASE-22285
>                 URL: https://issues.apache.org/jira/browse/HBASE-22285
>             Project: HBase
>          Issue Type: New Feature
>          Components: regionserver
>            Reporter: Aman Poonia
>            Assignee: Aman Poonia
>            Priority: Minor
>
> There are scenarios where we have seen around 5% of total regions with a size of 0 bytes and another 5-6 % regions with size in a few bytes. These kinds of regions increase with time considering we have TTL over the rows. 
> After exploring the option of RegionNormalizer and doing some quick runs we found that that is not suitable considering it also splits the regions and merges to normalize. What we really want is to split as per Split policy and merge very small regions with adjacent regions to make sure we reduce 0-byte regions.
> We can plugin this normalizer using the property "hbase.master.normalizer.class"



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