[jira] [Comment Edited] (HBASE-17462) Investigate using sliding window for read/write request costs in StochasticLoadBalancer

["Tim Brown (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-17462?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15830861#comment-15830861 ] 

Tim Brown edited comment on HBASE-17462 at 1/20/17 12:05 AM:
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The regionLoadList has a configurable size. By default it is 15 and controlled by "hbase.master.balancer.stochastic.numRegionLoadsToRemember".

For performance, I can attach some screenshots of charts that look at the average number of requests per region server. If you want more in depth analysis let me know.


was (Author: timbrown):
The regionLoadList has a configurable size. By default it is 15 and controlled by `hbase.master.balancer.stochastic.numRegionLoadsToRemember`.

For performance, I can attach some screenshots of charts that look at the average number of requests per region server. If you want more in depth analysis let me know.

> Investigate using sliding window for read/write request costs in StochasticLoadBalancer
> ---------------------------------------------------------------------------------------
>
>                 Key: HBASE-17462
>                 URL: https://issues.apache.org/jira/browse/HBASE-17462
>             Project: HBase
>          Issue Type: Improvement
>            Reporter: Ted Yu
>            Assignee: Tim Brown
>              Labels: patch
>         Attachments: HBASE-17462.patch
>
>
> In the thread, http://search-hadoop.com/m/HBase/YGbbyUZKXWALkX1, Timothy was asking whether the read/write request costs in StochasticLoadBalancer should be calculated as rates.
> This makes sense since read / write load on region server tends to fluctuate over time. Using sliding window would reflect more recent trend in read / write load.
> Some factors to consider:
> The data structure used by StochasticLoadBalancer should be concise. The
> number of regions in a cluster can be expected to approach 1 million. We
> cannot afford to store long history of read / write requests in master.
> Efficiency of cost calculation should be high - there're many cost
> functions the balancer goes through, it is expected for each cost function
> to return quickly. Otherwise we would not come up with proper region
> movement plan(s) in time.



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