Re: Should we get rid of custom_variable_classes altogether?

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Dimitri Fontaine <dimitri@2ndQuadrant.fr>
Cc: David Fetter <david@fetter.org>, Andrew Dunstan <andrew@dunslane.net>, Magnus Hagander <magnus@hagander.net>, pgsql-hackers@postgresql.org
Date: 2011-10-03T23:07:31Z
Lists: pgsql-hackers
Dimitri Fontaine <dimitri@2ndQuadrant.fr> writes:
> Tom Lane <tgl@sss.pgh.pa.us> writes:
>> No, because there are people who do intentionally use placeholder
>> variables as session-local storage, and that would be taking away
>> that capability.

> Or do you want to open SET typo.wrogn TO 'foobar' to just work silently?

Well, right at the moment it *does* work silently, as long as the prefix
is one you listed in custom_variable_classes.  I don't think we want to
take that away, and in particular I don't want to assume that every
variable will be declared in advance.  It's a fairly safe bet that there
are some apps out there that would be broken by such a requirement.

At the same time, I'd kind of like to see a facility for declaring such
variables, if only so you could define them to be bool/int/real not just
strings.  But this is getting far afield from the immediate proposal,
and no I'm not volunteering to do it.

			regards, tom lane