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https://issues.apache.org/jira/browse/HBASE-26251?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Duo Zhang resolved HBASE-26251.
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Fix Version/s: 3.0.0-alpha-2
2.5.0
Hadoop Flags: Reviewed
Resolution: Fixed
Merged to master and branch-2.
Thanks [~GeorryHuang] for contributing and [~bbeaudreault] for reviewing!
> StochasticLoadBalancer metrics should update even if balancer doesn't run
> -------------------------------------------------------------------------
>
> Key: HBASE-26251
> URL: https://issues.apache.org/jira/browse/HBASE-26251
> Project: HBase
> Issue Type: Improvement
> Reporter: Bryan Beaudreault
> Assignee: Zhuoyue Huang
> Priority: Minor
> Fix For: 2.5.0, 3.0.0-alpha-2
>
>
> Currently we only update StochasticLoadBalancerMetrics at the very end of a
> balancer run, once a plan has been found. In fact, we update the metrics
> based on that plan even if we don't end up executing the plan, which seems
> incorrect.
> Regardless of whether the balancer decides to run or not, cluster costs are
> changing all the time. Since we don't update these metrics any other time,
> operators miss out on important information about the balance of their
> cluster over time.
> I briefly looked into it and it would be relatively trivial to add another
> call to updateStochasticCosts at the beginning of the balanceTable method,
> before we determine if the cluster is in need of balancing. This would be an
> improvement but would still miss cases where the balancer is disabled or
> unable to run due to regions in transition, etc.
> It would be good if we could make it so updateStochasticCosts get called
> periodically regardless of whether the balancer is enabled or can run.
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