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HBase >> mail # dev >> Coprocessor Loading

20seconds@... 2011-04-22, 15:05
Mingjie Lai 2011-04-25, 18:03
20seconds@... 2011-04-26, 07:29
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Re: Coprocessor Loading
To get an idea how they are loaded, you can follow the HRegion constructor,
there is a call to instantiate CoprocessorHost.
      this.coprocessorHost = new RegionCoprocessorHost(this, rsServices,
Every Region has one instance of CoprocessorHost, and in its constructor,
you see calls to loadSystemCoprocessors(..), and loadTableCoprocessors(..).

If you follow the above calls, you should get the idea.

[Note this is a "Region level" coprocessor but its good enough to give you
an idea what happens for Master and Wal too. Then there are
EndPointCoprocessor, Observers(for Master, Region and WAL). Mingjie's blog
is a nice piece to get started with them.

Hope this helps,
On Tue, Apr 26, 2011 at 1:29 AM, <[EMAIL PROTECTED]> wrote:

> Hi,
> thanks for your answer. But I was more concerned how the loading actually
> occurs inside HBASE (where is the configuration read and the coprocessor
> actually loaded). I already got a rough feeling by browsing the code but
> still unsure about the details.
> Any pointers are appreciated
> Jörg
> -----Ursprüngliche Nachricht-----
> Von: "Mingjie Lai" <[EMAIL PROTECTED]>
> Gesendet: 25.04.2011 20:03:00
> Betreff: Re: Coprocessor Loading
> Hi JS.
> Please take a look at ``Coprocessor Class Loading'' section of this blog
> post:
> http://hbaseblog.com/2010/11/30/hbase-coprocessors/
> The post is a little bit out-of-date because the coprocessor has been
> improved since then. But the class loading is about the same.
> Mingjie
> On 04/22/2011 08:05 AM, [EMAIL PROTECTED] wrote:
> > Hi,
> > we are just trying to understand how Coprocessors are exactly loaded.
> > Is there some overview a) when this happens in the loading and b) which
> classes are involved.
> >
> > Thanks for your support
> > JS
> >