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https://issues.apache.org/jira/browse/HBASE-16030?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15336324#comment-15336324
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Tianying Chang edited comment on HBASE-16030 at 6/19/16 6:22 AM:
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[~enis] sure, I can make another patch. Question, by increasing the flush delay
time, the flush request will stay in the queue for 30 minutes. Will this cause
any issue?
was (Author: tychang):
@enis sure, I can make another patch. Question, by increasing the flush delay
time, the flush request will stay in the queue for 30 minutes. Will this cause
any issue?
> 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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