Rename trace_userlocks? WAS Re: LOCK_DEBUG is busted

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers(at)postgresql(dot)org
Subject: Rename trace_userlocks? WAS Re: LOCK_DEBUG is busted
Date: 2011-11-11 14:40:29
Message-ID: 201111111440.pABEeTG20409@momjian.us
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Robert Haas wrote:
> On Thu, Nov 10, 2011 at 5:07 PM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> > Tom Lane wrote:
> >> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> >> > It's possible to compile the source tree with LOCK_DEBUG defined, but
> >> > the resulting postgres promptly dumps core, due to the fact that
> >> > user_lockmethod doesn't supply any value for trace_flag; thus, the
> >> > first LockReleaseAll(USER_LOCKMETHOD) dereferences a NULL pointer.
> >> > This is the result of the following commit:
> >>
> >> > commit 0180bd6180511875db046bf8ddcaa633a2952dfd
> >>
> >> +1 for just reverting that commit. ?I'm not sure how much use the
> >> LOCK_DEBUG infrastructure has in exactly its current form, but I can
> >> certainly imagine wanting to use it or some variant of it to debug
> >> tough problems. ?If it's gone entirely, people would have to reinvent
> >> most of it for that type of debugging. ?On the other side of the coin,
> >> I don't have a clear enough use-case for it to want to spend time
> >> right now on redesigning it, nor a clear idea of exactly what changes
> >> might make it more useful. ?So I think we should just revert and
> >> not spend additional effort now.
> >
> > I am confused. ? I thought it was lock_debug referencing user locks that
> > was broken. ?Does lock_debug need user locks?
>
> It supports tracing them.
>
> The point is, they're not gone.

Now that we know that the GUC trace_userlocks is used for advisory
locks, should we rename it to trace_advisory_locks?

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +

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