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From chenwenhui <c77...@163.com>
Subject Re:Re: What is the difference between "hbase.server.thread.wakefrequency" and "hbase.hregion.majorcompaction"?
Date Fri, 22 Aug 2014 01:21:20 GMT
Maybe i can not present my question clearly.
I indeed understand the mean of the combination condition("hbase.server.thread.wakefrequency"
and "server.compactchecker.interval.multiplier"),  i also know that its product is the period
that check whether trigger compaction.
For another combination condition("hbase.hregion.majorcompaction(7 days by default)" and "hbase.hregion.majorcompaction.jitter"),
i understand it is also a condition to trigger compaction. right? if so, what is the relation
between the two combination condition?

At 2014-08-21 09:54:51, "Ted Yu" <yuzhihong@gmail.com> wrote:
>See explanation for the following parameter (from hbase refguide)
>The number that determines how often we scan to see if compaction is
>necessary. Normally, compactions are done after some events (such as
>memstore flush), but if region     didn't receive a lot of writes for some
>time, or due to different compaction policies, it may be necessary to check
>it periodically. The interval between checks is hbase.
>server.compactchecker.interval.multiplier multiplied by
>Default. 1000
>On Thu, Aug 21, 2014 at 3:01 AM, chenwenhui <c77_cn@163.com> wrote:
>> From the book named "Hbase: the Definitive Guide", i know that there is a
>> condition to trigger major compaction, i.e. a thread controlled by
>> "hbase.server.thread.wakefrequency(10 seconds by default)" and
>> "hbase.server.thread.wakefrequency.multiplier" checks periodically whether
>> major compaction.
>> But i also read that the other conditon, both
>> "hbase.hregion.majorcompaction(7 days by default)" and
>> "hbase.hregion.majorcompaction.jitter", can also trigger major compaction.
>> As my understanding, because of the former, the latter condition will
>> never execute.
>> Maybe i mis-undertand the two conditions, anyone can explain the
>> difference between the two condtions? Thanks!
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