Tianying Chang created HBASE-16027:
--------------------------------------
Summary: All Regions are flushed at about same time when
MEMSTORE_PERIODIC_FLUSH is on, causing flush spike
Key: HBASE-16027
URL: https://issues.apache.org/jira/browse/HBASE-16027
Project: HBase
Issue Type: Bug
Components: hbase, Performance
Affects Versions: 1.2.1
Reporter: Tianying Chang
Assignee: Tianying Chang
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.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
