Stephen Robert Norris <srn(at)commsecure(dot)com(dot)au> writes:
> I've already strace'ed the idle backend, and I can see the SIGUSR2 being
> delivered just before everything goes bad.
Yes, but what happens after that?
If you don't see anything obvious by examining a single process, maybe
strace'ing the postmaster + all descendant processes would offer a
better viewpoint.
> What resource would you think idle backends might be exhausting?
Difficult to say. I suspect your normal load doesn't have *all* the
backends trying to run queries at once. But in any case the SIGUSR2
event should only produce a momentary spike in load, AFAICS.
regards, tom lane