Re: Should we get rid of custom_variable_classes altogether?

On Sun, Oct 2, 2011 at 23:05, Tom Lane  wrote:
> During the discussion of Alexey Klyukin's rewrite of ParseConfigFile,
> considerable unhappiness was expressed by various people about the
> complexity and relative uselessness of the custom_variable_classes GUC.
> While working over his patch just now, I've come around to the side that
> was saying that this variable isn't worth its keep.  We don't have any
> way to validate whether the second part of a qualified GUC name is
> correct, if its associated extension module isn't loaded, so how much
> point is there in validating the first part?  And the variable is
> certainly a pain in the rear both to DBAs and to the GUC code itself.

Don't forget that there are usecases for variables under
custom_variable_classes that aren't actually associated with
extensions (as general session-shared-variables). Though I guess if it
was somehow restricted to extensions, those who needed that could just
rewrap all their code as extensions - though that would make it less
convenient.

The point being that even if you *could* validate them somehow against
a static list, requiring that might not be a good idea.


> So at this point I'd vote for just dropping it and always allowing
> custom (that is, qualified) GUC names to be set, whether the prefix
> corresponds to any loaded module or not.

Seems reasonable to me.

-- 
 Magnus Hagander
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