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HBase, mail # user - About HBase Region Flushes


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Varun Sharma 2013-01-23, 00:13
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xkwang bruce 2013-01-23, 01:56
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Re: About HBase Region Flushes
ramkrishna vasudevan 2013-01-23, 02:54
Hi Varun

Generally when the memstore size has reached for the region, the writes are
not blocked except for a fraction of a time till a new memstore is created
so that new puts can go into the newly created memstore.

But if you have a heavy flow of puts happening and that is increasing the
size of the memstore to more than blockingmemstoresize, then the
RegionServer tries to pick the biggest region and tries to flush that
region until the memstore size comes below the lower threshold.

During this time if any puts happens to this region then the puts are
blocked.  If you see this msg in the logs saying "Blocking updates" very
frequently then it means the region is heavy and it will affecting your
write through put.

Hope this helps.

Regards
Ram

On Wed, Jan 23, 2013 at 7:26 AM, xkwang bruce <[EMAIL PROTECTED]>wrote:

> hello Varun,
>
> >>>: Are reads and writes blocked while the memstore is being flushed ?
> Another empty memstore will be used for writes.
>
> cheers
>
>
> 2013/1/23 Varun Sharma <[EMAIL PROTECTED]>
>
> > Hi,
> >
> > I have a question about hbase region flushes. Are reads and writes
> blocked
> > while the memstore is being flushed ?
> >
> > Thanks !
> >
>