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https://issues.apache.org/jira/browse/HBASE-16030?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15339804#comment-15339804
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Tianying Chang commented on HBASE-16030:
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[~enis] I feel that we should have check for configurable value to be a
non-negative to prevent user error. But it seems all the places for retrieving
the configurable value does not do any check. Is this the convention for HBase
that user has the responsibility make sure a reasonable value is used?
> 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: 2.0.0, 1.4.0, 1.3.1, 1.2.3
>
> Attachments: Screen Shot 2016-06-15 at 11.35.42 PM.png, Screen Shot
> 2016-06-15 at 11.52.38 PM.png, hbase-16030-v2.patch, 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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