Re: 9.1.11 - many backends in "semtimedop" syscall

On Thu, Mar 06, 2014 at 11:56:06AM -0500, Tom Lane wrote:
> hubert depesz lubaczewski <depesz@depesz.com> writes:
> > Thread 1 (LWP 21422):
> > #0  0x00007ffa60da2dc7 in semop () from /lib/x86_64-linux-gnu/libc.so.6
> > No symbol table info available.
> > #1  0x00000000005f65e8 in PGSemaphoreLock ()
> > No symbol table info available.
> > #2  0x0000000000636125 in LWLockAcquire ()
> > No symbol table info available.
> > #3  0x0000000000630f91 in LockAcquireExtended ()
> > No symbol table info available.
> > #4  0x000000000062f88c in LockRelationOid ()
> > No symbol table info available.
> > #5  0x0000000000470f6d in relation_open ()
> > No symbol table info available.
>
> Huh.  Looks like it's blocked trying to acquire one of the lock-partition
> LWLocks, which is odd because those ought never be held very long.
> Somebody else has failed to release that LWLock, looks like.
>
> Did you by any chance capture stack traces from all of the backends?
> The interesting one would be the one that *doesn't* look like this.
> Or possibly there's more than one such.

I didn't have a chance to do it. Can try if there is a way to get trace
*without* making core (sorry, my c/gdb knowledge is very, very limited).

Best regards,

depesz

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