On Tue, Apr 12, 2022 at 3:22 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Yeah. It's a very long way from "changing shared memory sizes here
> doesn't work" to "no extension is allowed to change any GUC at load
> time". A counterexample is that it's not clear why an extension
> shouldn't be allowed to define a GUC using DefineCustomXXXVariable
> and then immediately set it to some other value. I think trying to
> forbid that across-the-board is going to mostly result in breaking
> a lot of cases that are perfectly safe.
Hmm, that's an interesting case which I hadn't considered. It seems
like sort of a lame thing to do, because why wouldn't you just create
the GUC with the right initial value instead of modifying it after the
fact? But maybe there's some use case in which it makes sense to do it
that way. A read-only GUC that advertises some calculated value,
perhaps?
--
Robert Haas
EDB: http://www.enterprisedb.com