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From Ted Yu <yuzhih...@gmail.com>
Subject Re: Couple notes and questions on RegionObserver's
Date Thu, 25 Jul 2013 04:05:22 GMT
Take a look at the following call chain:

HRegionServer#run() -> waitOnAllRegionsToClose(abortRequested) ->
closeRegionIgnoreErrors(hri, abort) -> closeRegion()

On Wed, Jul 24, 2013 at 8:48 PM, Vladimir Rodionov
<vrodionov@carrieriq.com>wrote:

> abort is always false, Ted. Its true only in unit tests.
>
> Best regards,
> Vladimir Rodionov
> Principal Platform Engineer
> Carrier IQ, www.carrieriq.com
> e-mail: vrodionov@carrieriq.com
>
> ________________________________________
> From: Ted Yu [yuzhihong@gmail.com]
> Sent: Wednesday, July 24, 2013 8:44 PM
> To: dev@hbase.apache.org
> Subject: Re: Couple notes and questions on RegionObserver's
>
> For #3 below, have you seen the following code in HRegion#doClose() ?
>
>     if (coprocessorHost != null) {
>
>       status.setStatus("Running coprocessor pre-close hooks");
>
>       this.coprocessorHost.preClose(abort);
>
>     }
> Cheers
>
> On Wed, Jul 24, 2013 at 8:31 PM, Vladimir Rodionov
> <vrodionov@carrieriq.com>wrote:
>
> > On design:
> >
> > Why is the instance per region if we specify region in every call to
> > RegionObserver anyway( through RegionCoprocessorEnvironment)? The
> > coprocessor instance is attached to every table region and
> > receives the very same region as a parameter of every call except
> > start/stop?
> >
> > I want one coprocessor instance per RegionServer->Table or I want one
> > Instance per RegionServer. Its not feasible currently?
> >
> > On implementation:
> > 1.  stop() is always called after postClose - this one I tested
> > 2. start() is always called before preOpen() ?
> >
> > OK. this is annoying. The contract of start/stop becomes unclear. I
> though
> > that we start should be called on coprocessor load and
> > stop - on RS shutdown.
> >
> > 3. abortRequested parameter is always false. Yes, its for testing but how
> > can I distinguish disabling table and RS shutdown?
> >
> > 4. How can I intercept (or get notified on) RS shutdown request from
> > inside a coprocessor?
> >
> > and the last one:
> >
> > 5. I have one table and one region - hence one coprocessor instance. When
> > I disable table I observe the following sequence of calls:
> >
> > preClose
> > preClose
> > preClose
> > postClose
> > stop
> >
> > preClose is called three times in row. Is it feature or a bug?
> >
> > This was tested with MiniHBaseCluster. Hbase 0.94.6.1
> >
> > Best regards,
> > Vladimir Rodionov
> > Principal Platform Engineer
> > Carrier IQ, www.carrieriq.com
> > e-mail: vrodionov@carrieriq.com
> >
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> disclosure or distribution of this message or its attachments, in any form,
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