Re: [HACKERS] update_pg_pwd trigger does not work very well

wieck(at)debis(dot)com (Jan Wieck) writes:
>>>> itself do nothing except set a flag variable. The flag is examined
>>>> somewhere in xact.c after successful completion of a transaction,
>>>> and if it's set then we run a new transaction cycle in which we
>>>> read pg_shadow and write pg_pwd.
>>
>> If you think that this is okay (and not just a hack), then go for it.

> I consider it a hack, since this particular trigger needs a
> global flag known explicitly by xact routines. I like general
> solutions instead.

Well, really it's pg_pwd itself that is a hack --- we wouldn't need
to be worrying about all this if pg_pwd didn't exist outside the
database/transaction universe. But I don't think it'd be wise to
try to bring the postmaster into that universe, so we're stuck with
a hack for exporting user authorization info.

If we had examples of other problems that could be solved by such
a mechanism, then I'd agree with Jan that we ought to invent a general
after-commit-do mechanism. But I don't recall users clamoring for it,
so I question whether the extra effort is worthwhile.

regards, tom lane