Re: postgres processes spending most of their time in the

On Fri, 28 Dec 2001, Tom Lane wrote:

> [ scratches head ... ]  Well, the LWLock stuff is new code, and it's not
> out of the question that there's a bug in it.  I can't see where though,
> and I don't have enough info to proceed further.

Thanks for all your attention so far.

> We need to understand what the dynamic behavior is in your situation.
> Can you poke into it further, or perhaps grant access to your machine
> to someone who can?

I can provide as much dumping, logging, and tracing as you want, with the
single constraint of upstream network bandwith.  I don't think files
larger than 100MB will be practical.  I don't know what logging will be
useful, so someone will have to tell me what to do.

I don't think I can let anybody have access to this particular machine but
if I can reduce things to a simple testcase on another machine, I'll grant
access to that.

> One thing that would be quite useful is a more-detailed strace that
> would let us determine whether each semop is a lock or unlock.  Can you
> get strace to record the user-space PC of the semop() caller?  If no
> joy there, maybe beefing up the LWDEBUG log printouts would produce
> a useful trace.

strace unfortunately doesn't deref the sembuf structure in semop.

-jwb