Re: Process wakeups when idle and power consumption

Peter Geoghegan <peter(at)2ndquadrant(dot)com> writes:
> On 5 May 2011 22:22, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> What that really means is that any WaitOnLatch call with a finite
>> timeout ought to be viewed with a jaundiced eye. Ideally, we want them
>> all to be waiting for latch release and nothing else. I'm concerned
>> that we're going to be moving towards some intermediate state where we
>> have WaitOnLatch calls with very long timeouts, because the longer the
>> timeout, the worse the problem gets on platforms that have the problem.
>> If you have say a 1-minute timeout, it's not difficult to believe that
>> you'll basically never wake up because of random signals resetting the
>> timeout.

> Unless all signal handlers for signals that we expect call SetLatch()
> anyway, as in this case.

It's signals that we don't expect that I'm a bit worried about here.

In any case, the bottom line is that having a timeout on WaitOnLatch
is a kludge, and we should try to avoid it.

regards, tom lane