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https://issues.apache.org/jira/browse/HBASE-16030?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Tianying Chang updated HBASE-16030:
-----------------------------------
    Fix Version/s: 1.2.1
           Status: Patch Available  (was: In Progress)

> All Regions are flushed at about same time when MEMSTORE_PERIODIC_FLUSH is 
> on, causing flush spike
> --------------------------------------------------------------------------------------------------
>
>                 Key: HBASE-16030
>                 URL: https://issues.apache.org/jira/browse/HBASE-16030
>             Project: HBase
>          Issue Type: Improvement
>    Affects Versions: 1.2.1
>            Reporter: Tianying Chang
>            Assignee: Tianying Chang
>             Fix For: 1.2.1
>
>         Attachments: hbase-16030.patch
>
>
> In our production cluster, we observed that memstore flush spike every hour 
> for all regions/RS. (we use the default memstore periodic flush time of 1 
> hour). 
> This will happend when two conditions are met: 
> 1. the memstore does not have enough data to be flushed before 1 hour limit 
> reached;
> 2. all regions are opened around the same time, (e.g. all RS are started at 
> the same time when start a cluster). 
> With above two conditions, all the regions will be flushed around the same 
> time at: startTime+1hour-delay again and again.
> We added a flush jittering time to randomize the flush time of each region, 
> so that they don't get flushed at around the same time. We had this feature 
> running in our 94.7 and 94.26 cluster. Recently, we upgrade to 1.2, found 
> this issue still there in 1.2. So we are porting this into 1.2 branch. 



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