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From "Clint Morgan" <clint....@gmail.com>
Subject Re: Other CC examined in HBase transaction model?
Date Tue, 07 Oct 2008 23:36:46 GMT
OCC got into 0.18.0. See the package.html javadoc in
o.a.h.h.client.transactional for setup/usage instructions.

My secondary index patch is not in the trunk (or release) yet. You can try
it out here: https://issues.apache.org/jira/browse/HBASE-883. If you do try
it out, please comment in the jira how it worked, how you like the API, etc.
I attempt to respect transactional properties with the index updates, but
this has not been thoroughly tested.

cheers,
-clint

On Tue, Oct 7, 2008 at 3:54 PM, Ski Gh3 <skigh3@gmail.com> wrote:

> Two quick follow-up questions:
>
> Which version of hbase do we need to download in order to use to OCC
> functionality?0.18.0?
> I guess no setting is required by the user, where hregionserver was used
> will now be transactionalregion, right?
>
> How can this be combined with secondary index? Didn't find the code for
> that
> in 0.18.0, is that still
> work in progress?
>
> Thanks a lot!
>
> On Mon, Oct 6, 2008 at 2:26 PM, Clint Morgan <clint.a.m@gmail.com> wrote:
>
> > I implemented the OCC functionality. Went that route because it seemed
> > relatively straightforward and has acceptable performance for our
> > workloads.
> > Also I saw something somewhere that made me think that google was using
> OCC
> > for transactions in AppEngine.
> >
> > My intuition is that where the OCC approach really gets into trouble is
> > when
> > transactions start to frequently conflict (EG, when the "optimistic" hope
> > no
> > longer holds). Of course, as you increase the life of a transaction, you
> > increase the probability it will conflict with another.
> >
> > I don't know enough about timstamp-, or MV-CCs to compare "scalability"
> to
> > the OCC approach.
> >
> > -clint
> >
> > On Mon, Oct 6, 2008 at 11:19 AM, Jaeyun Noh <metalain@gmail.com> wrote:
> >
> > > Hi,
> > >
> > > I looked at the source codes implemented to support Multi-region
> > > transaction
> > > feature. (HBASE-669)
> > > It uses optimistic concurrency control. Did any guys consider other CC
> > like
> > > timestamp-based CC or multiversion CC?
> > >
> > > I think it's okay in read-dominated and relatively short transaction
> > > workloads. In other case, is MVCC more scalable rather than OCC?
> > > What do you think of pros/cons of other concurrency control schemes in
> > > Hbase
> > > transactions?
> > >
> > > Just I'm curious that hbase transaction uses other CCs or not.
> > >
> > > Regards,
> > > Jaeyun Noh.
> > >
> >
>

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