Re: patch: shared session variables

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: patch: shared session variables
Date: 2012-08-30 19:39:00
Message-ID: 28284.1346355540@sss.pgh.pa.us
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Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Thu, Aug 30, 2012 at 2:18 PM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:
>> 2012/8/30 Robert Haas <robertmhaas(at)gmail(dot)com>:
>>> On Tue, Aug 14, 2012 at 3:46 AM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:
>>>> patch that implements "shared" client/server session variables

>>> I don't really see what we can do with this that we can't do without this.

>> a motivation for this patch was discussion about parametrised DO
>> statement - and simple possibility of access to host variables (psql)
>> variables from server - PL scripts.
>>
>> It is based on Tom's and Magnus's ideas - it is secure, because only
>> variables explicitly mentioned in shared namespace are "shared".

> Sure, but you could get to the same place by issuing a SET command for
> just the particular variable you want to use with DO. You don't
> really need a magic facility for it.

FWIW, I don't particularly care for this idea either. It may be less
klugy than the original proposal, but it's still a kluge. Also, it's
not very sensible to consider extensions of this sort unless we have
ambitions of turning psql into a full-fledged scripting language,
with conditionals and iteration at the very least. I do not want
to go there. If you need scripting capability, there are lots of
better tools out there already.

regards, tom lane

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