Re: LWLockAcquire problems

Scott Shattuck <ss@technicalpursuit.com> writes:
> On Tue, 2002-08-13 at 22:42, Tom Lane wrote:
>> Scott Shattuck <ss@technicalpursuit.com> writes:
> I'm seeing the following error about once a week or so:
> 2002-08-13 12:37:28 [24313]  FATAL 1:  LWLockAcquire: can't wait without
> a PROC structure
>> 
>> Oh?  I'd love to see what makes this happen.  Can you give more context?

> I haven't been able to get any detailed correlation on what causes this
> over the past week and it's not happening often enough for me to turn on
> heavy logging to catch it a second time.

What would actually be useful is a stack backtrace from the point of the
error.  If you are willing, I would suggest replacing the line           elog(FATAL, "LWLockAcquire: can't wait without
aPROC structure");
 
with           abort();
(in 7.2 this is about line 275 of src/backend/storage/lmgr/lwlock.c) so
that a core dump is forced when the error occurs.  Then you could get a
backtrace from the corefile.

The downside of this is that the abort() will cause a database-wide
restart; I can understand if you don't want that to happen in a
production system.  But right at the moment I see no other way to
gather more info ...
        regards, tom lane