Re: Stuck Spinlock Error Message

Ludwig Isaac Lim <ludz_lim(at)yahoo(dot)com> writes:
> I'm guessing that the spinlock error occurs after
> there are around hundreds (or thousands) of queued
> postmaster processes.

Thousands? How large is your max_connections parameter, anyway
(and do you really have big enough iron to support it)?

The stuck spinlock error implies that some work that should have
taken a fraction of a microsecond (namely the time to check and update
the internal state of an LWLock structure) took upwards of a minute.

Since the process holding the spinlock could lose the CPU, it's
certainly physically possible for the actual duration of holding the
spinlock to be much more than a microsecond. But the odds of losing
the CPU while holding the spinlock are not large, since it's held for
just a small number of instructions. And to get an actual "stuck
spinlock" failure would imply that the holding process didn't get
scheduled again for more than a minute (while some other process that
wanted the spinlock *did* get scheduled again --- repeatedly). I
suppose this is possible if your machine is sufficiently badly
overloaded.

regards, tom lane