Re: A bad behavior under autocommit off mode

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Peter Eisentraut <peter_e(at)gmx(dot)net>, Barry Lind <blind(at)xythos(dot)com>, Neil Conway <neilc(at)samurai(dot)com>, Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: A bad behavior under autocommit off mode
Date: 2003-03-26 15:04:13
Message-ID: 200303261504.h2QF4DQ03703@candle.pha.pa.us
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How about sending an INFO or special taged message to the client when
there is a GUC change, and have report_changes as a GUC variable that
controls it?

---------------------------------------------------------------------------

Tom Lane wrote:
> Peter Eisentraut <peter_e(at)gmx(dot)net> writes:
> > And where does it stop? There are about a dozen GUC variables that will
> > break an application as a whole if they don't have the value expected by
> > the application. Do we need to install guards against all of these?
>
> The issue in my mind is not what will break an application, but what
> will break a client-side library. The application knows, in some sense,
> what settings it has selected -- either because it did explicit SETs or
> because it's coded expecting certain values to be supplied via the GUC
> default mechanisms. And the server knows what values have been set,
> too. But the client-side library is out of the loop. We need to bring
> it into the loop, at least for the values it needs to know about (and
> yes, I agree that that's not a very well-defined set, but we can easily
> set up the protocol to allow an expansible set of variables to be
> transmitted).
>
> I think that "don't do that" is not an acceptably robust solution.
> Building software that falls over because someone exercised a perfectly
> legitimate feature of another part of the system just isn't my idea of
> the way to build stuff. We've had to put up with some cases of that
> because we didn't want to change the protocol to fix it --- but now is
> our opportunity to fix it.
>
> regards, tom lane
>
>
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Bruce Momjian | http://candle.pha.pa.us
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