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https://issues.apache.org/jira/browse/HBASE-12451?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14212024#comment-14212024
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zhangduo commented on HBASE-12451:
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I think the goal of IncreasingToUpperBoundRegionSplitPolicy is splitting fast
when region count is small(especially when smaller than region server count),
and falling back to ConstantSizeSplitPolicy when region count is larger than
regionserver count(or twice, it depends) which means we already have the
ability to distribute request to every regionserver.
Add a minimum split size will break the first goal, right? And actually, there
is a "hbase.increasing.policy.initial.size" configuration in
IncreasingToUpperBoundRegionSplitPolicy which specify the initial(minimum)
split size. And if you do not like the curve of split size, I think we should
introduce a new split policy instead?
> IncreasingToUpperBoundRegionSplitPolicy may cause unnecessary region splits
> in rolling update of cluster
> --------------------------------------------------------------------------------------------------------
>
> Key: HBASE-12451
> URL: https://issues.apache.org/jira/browse/HBASE-12451
> Project: HBase
> Issue Type: Bug
> Reporter: Liu Shaohui
> Assignee: Liu Shaohui
> Priority: Minor
> Fix For: 2.0.0
>
> Attachments: HBASE-12451-v1.diff
>
>
> Currently IncreasingToUpperBoundRegionSplitPolicy is the default region split
> policy. In this policy, split size is the number of regions that are on this
> server that all are of the same table, cubed, times 2x the region flush size.
> But when unloading regions of a regionserver in a cluster using
> region_mover.rb, the number of regions that are on this server that all are
> of the same table will decrease, and the split size will decrease too, which
> may cause the left region split in the regionsever. Region Splits also
> happens when loading regions of a regionserver in a cluster.
> A improvment may set a minimum split size in
> IncreasingToUpperBoundRegionSplitPolicy
> Suggestions are welcomed. Thanks~
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