hbase-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Ted Yu <yuzhih...@gmail.com>
Subject Re: Are coprocessor really bad?
Date Sat, 15 Mar 2014 23:56:20 GMT
I went over the thread JMS pointed to.
Gary H has responded there. As he said:

bq. not many HBase contributors actually participate here. You will get a
much better response on the HBase users mailing list

Cheers


On Sat, Mar 15, 2014 at 4:42 PM, Andrew Purtell <apurtell@apache.org> wrote:

> I think a misunderstanding of what we want to accomplish is the issue.
>
> We designed coprocessors to function as in-server extensions for HBase core
> developers and system integrators. Specifically, we wanted to flexibly
> extend server functions through composition rather than use the brittle and
> inflexible class inheritance way which was done up to that point. I think
> you can look at our security coprocessors as the canonical example of
> extensions as coprocessor done successfully. There is also Apache Phoenix.
> There are also a few coprocessor success stories at every Hadoop or HBase
> conference I have been at since they went in.
>
> Explicitly, we have a non-goal of trying to be OSGi-type-friendly for
> random user applications. Frankly, coprocessors are not meant for loading
> *and* unloading extensions. They are meant for loading extensions over the
> lifetime of the regionserver. There are a lot of corner cases we just don't
> have to care about and spend time on if coprocessor extensions effectively
> have the same lifecycle as the RegionServer. They live within the
> RegionServer process and can do just about anything, so can we really
> guarantee any state changes they might make deliberately or through
> implementation bugs can be cleaned up upon unload? No.
>
>
>
> On Sat, Mar 15, 2014 at 4:16 PM, Jean-Marc Spaggiari <
> jean-marc@spaggiari.org> wrote:
>
> > History is here:
> >
> >
> http://www.linkedin.com/groupItem?view=&gid=1407857&type=member&item=5849626646549659651&trk=groups_most_recent-0-b-cmr&goback=.gmr_1407857
> >
> > Not sure but I think you need to register to the group to read it.
> >
> > Basically, people often complains about coprocs. Like, can not reload
> them
> > dynamically, need to change the jars names, not well implemented, etc.
> >
> > However, it's still there, and others are using it.
> >
> > The only time I thought about using it, I have been convinced to not do
> it
> > and ended up using another solution.
> >
> > So was wondering what is the situation around coprocessors.
> >
> > Hope it's more clear now.
> >
> > JM
> >
> >
> > 2014-03-15 18:50 GMT-04:00 Andrew Purtell <apurtell@apache.org>:
> >
> > > On Sat, Mar 15, 2014 at 2:40 PM, Jean-Marc Spaggiari <
> > > jean-marc@spaggiari.org> wrote:
> > >
> > > > This caught my attention on the LinkedIn HBase group:
> > > >
> > > > "Coprocessors are not well thought out or implemented in HBase. "
> > > >
> > >
> > > I'm sorry, but dropping a disparaging statement like that without
> context
> > > or explanation is the definition of trolling J-M.
> > >
> > >
> > >
> > > --
> > > Best regards,
> > >
> > >    - Andy
> > >
> > > Problems worthy of attack prove their worth by hitting back. - Piet
> Hein
> > > (via Tom White)
> > >
> >
>
>
>
> --
> Best regards,
>
>    - Andy
>
> Problems worthy of attack prove their worth by hitting back. - Piet Hein
> (via Tom White)
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message