Re: Hot Standy introduced problem with query cancel behavior

From: Simon Riggs <simon(at)2ndQuadrant(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Joachim Wieland <joe(at)mcknight(dot)de>, Andres Freund <andres(at)anarazel(dot)de>, pgsql-hackers(at)postgresql(dot)org, Kris Jurka <books(at)ejurka(dot)com>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
Subject: Re: Hot Standy introduced problem with query cancel behavior
Date: 2010-01-07 17:32:25
Message-ID: 1262885545.19367.86413.camel@ebony
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On Thu, 2010-01-07 at 12:14 -0500, Tom Lane wrote:
> Simon Riggs <simon(at)2ndQuadrant(dot)com> writes:
> > On Thu, 2010-01-07 at 14:45 +0100, Joachim Wieland wrote:
> >> @Simon: Is there a reason why you have not yet removed recoveryConflictMode
> >> from PGPROC?
>
> > Unfortunately we still need a mechanism to mark which backends have been
> > cancelled already. Transaction state for virtual transactions isn't
> > visible on the procarray, so we need something there to indicate that a
> > backend has been sent a conflict. Otherwise we'd end up waiting for it
> > endlessly. The name will be changing though.
>
> While we're discussing this: the current coding with
> AbortOutOfAnyTransaction within ProcessInterrupts is *utterly* unsafe.
> I realize that's just a toy placeholder, but getting rid of it has to be
> on the list of stop-ship items. Right at the moment I'd prefer to see
> CONFLICT_MODE_ERROR always turned into CONFLICT_MODE_FATAL than to
> imagine this is going to work.

Hmmm. Can you check my current attempt? This may suffer this problem.

If, so can you explain a little more for me? Thanks.

--
Simon Riggs www.2ndQuadrant.com

Attachment Content-Type Size
another_recovery_cancel.patch text/x-patch 20.2 KB

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