Re: Modernizing our GUC infrastructure

Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> writes:
> út 6. 9. 2022 v 6:32 odesílatel Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
> napsal:
>> 1. Session variables can be persistent - so the usage of session variables
>> can be checked by static analyze like plpgsql_check

> more precious - metadata of session variables are persistent

Right ... so the question is, is that a feature or a bug?

I think there's a good analogy here to temporary tables. The SQL
spec says that temp-table schemas are persistent and database-wide,
but what we actually have is that they are session-local. People
occasionally propose that we implement the SQL semantics for that,
but in the last twenty-plus years no one has bothered to write a
committable patch to support it ... much less remove the existing
behavior in favor of that, which I'm pretty sure no one would think
is a good idea.

So, is it actually a good idea to have persistent metadata for
session variables? I'd say that the issue is at best debatable,
and at worst proven wrong by a couple of decades of experience.
In what way are session variables less mutable than temp tables?

Still, this discussion would be better placed on the other thread.

regards, tom lane