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https://issues.apache.org/jira/browse/HBASE-3609?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13018735#comment-13018735
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Ted Yu commented on HBASE-3609:
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For unit test, the region Ids created by mockClusterServers() have the same
value - because all the regions are created at almost the same time.
It will take a little more time to devise appropriate test case generation and
validate the balancing moves.
For the moment, I still base my improvement on the existing framework where
region count plays dominant factor.
One of the goals of this JIRA is to remove randomness from LoadBalancer so that
we can deterministically produce near-optimal balancing actions.
The new parameter, emptyRegionServerPresent, helps decide whether we should
move old and new regions to other servers.
I will upload a new patch where I describe the above in detail. I even plan to
blog about the history of HBASE-3586 and this JIRA.
To validate my latest patch, I need a little help from community participants.
Our use case creates hbase tables frequently in our flow with pre-split
regions. Since those regions get round-robin assigned initially, it is not easy
to reproduce what Stan experienced.
Thanks for the review and suggestion, Stack.
> Improve the selection of regions to balance; part 2
> ---------------------------------------------------
>
> Key: HBASE-3609
> URL: https://issues.apache.org/jira/browse/HBASE-3609
> Project: HBase
> Issue Type: Improvement
> Reporter: stack
> Assignee: Ted Yu
> Attachments: 3609-alternate.txt, 3609-empty-RS.txt,
> hbase-3609-by-region-age.txt, hbase-3609.txt
>
>
> See 'HBASE-3586 Improve the selection of regions to balance' for discussion
> of algorithms that improve on current random assignment.
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