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https://issues.apache.org/jira/browse/HBASE-16030?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15340748#comment-15340748
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Enis Soztutar commented on HBASE-16030:
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bq. It sounds also a problem if flush is stalled for 5 mins (although not as
bad as 30 mins)
Indeed.
bq. Feels like the right way of jittering should not be putting into a blocking
queue ahead of time. What do you think?
I think we can still jitter for more, but we have to solve the underlying
problem first. The correct solution might be to re-queue the request in regular
flush request with no-delay.
> 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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