Re: BUG #5609: Exclusive Locks & Permission

Sorry about that, I hit the submit button on accident before I finished typ=
ing out the issue.  But I guess there was enough there for you to understan=
d the problem.

Thanks for the quick response.

Is there any alternative I can use to prevent the exclusive lock (other tha=
n changing the app, we don't have access to the source code)?

Thanks,
Rob

-----Original Message-----
From: Tom Lane [mailto:tgl@sss.pgh.pa.us]=20
Sent: Monday, August 09, 2010 2:41 PM
To: Rob Brucks
Cc: pgsql-bugs@postgresql.org
Subject: Re: [BUGS] BUG #5609: Exclusive Locks & Permission=20

"Rob Brucks" <rob.brucks@rackspace.com> writes:
> The user's permissions need to be checked before requesting an exclusive
> lock on the table for the alter.

Unfortunately, that cure is as bad or worse than the disease.  It's not
possible to do a permissions check before acquiring any lock --- what if
somebody is changing the permissions under you, or even dropping or
renaming the table?  We could acquire sharelock, do the permissions
check, and then upgrade to exclusive lock; but lock upgrading has its
own unpleasant consequences, notably increased risk of deadlock.

So it's unlikely this is going to get changed.

            regards, tom lane


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