Re: LOCK_DEBUG is busted

On Thu, Nov 10, 2011 at 5:07 PM, Bruce Momjian <bruce@momjian.us> wrote:
> Tom Lane wrote:
>> Robert Haas <robertmhaas@gmail.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.

--
Robert Haas
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