Re: Still a loose end in GUC USERLIMIT stuff

Tom Lane wrote:
> As of CVS tip, an increase in a USERLIMIT parameter in postgresql.conf
> will be enforced against the sessions of superusers as well as everyone
> else. That's because I ifdef'd out this code:
>
> /*
> * If user is a superuser, he gets to keep his setting. We can't check
> * this unless inside a transaction, though. XXX in practice that
> * restriction means this code is essentially worthless, because the
> * result will depend on whether we happen to be inside a transaction
> * block when SIGHUP arrives. Dike out until we can think of something
> * that actually works.
> */
> #ifdef NOT_USED
> if (IsTransactionState() && superuser())
> return false;
> #endif
>
> It'd be better if it worked as originally intended, but this code cannot
> be made to do that with any reliability.
>
> The superuser() test has another problem besides what I mentioned in the
> comment, which is that its result will vary depending on SET SESSION
> AUTHORIZATION, SECURITY INVOKER function calls, and so on; so it might
> return an indication that has nothing to do with the privileges that
> were used when the GUC variable was set.
>
> Offhand the only reasonable way I can see to handle this is that *when a
> setting is made* we set a flag bit on the GUC variable showing whether
> it was set by a superuser or not, and then check that flag rather than
> the current superuser state when deciding whether to override the value.
> I am not sure it's really worth the trouble though. Also this would not
> be exactly the original coding intention, I think, because the original
> code attempted to protect the superuser's effective setting whether he
> had explicitly set the value or just inherited it from postgresql.conf.

This is tough, but looking at CVS it doesn't appear as you showed above.
Is there a later email that hasn't arrived yet?

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Bruce Momjian | http://candle.pha.pa.us
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