Re: Reducing power consumption on idle servers

Hi,

On 2022-03-10 17:50:47 +0000, Simon Riggs wrote:
> On Wed, 9 Mar 2022 at 01:16, Zheng Li <zhengli10(at)gmail(dot)com> wrote:
>
> > > 1. Standardize the hibernation time at 60s, using a #define
> > > HIBERNATE_DELAY_SEC 60
> >
> > I notice in patch 3 HIBERNATE_DELAY_SEC has been increased to 300
> > seconds, what’s the reasoning behind it? Is longer hibernation delay
> > better? If so can we set it to INT_MAX (the max timeout allowed by
> > WaitLatch()) in which case a worker in hibernation only relies on
> > wakeup? I think it would be nice to run experiments to verify that the
> > patch reduces power consumption while varying the value of
> > HIBERNATE_DELAY_SEC.
>
> Setting it to INT_MAX would be the same as not allowing a timeout,
> which changes a lot of current behavior and makes it less robust.

Most of these timeouts are a bad idea and should not exist. We repeatedly have
had bugs where we were missing wakeups etc but those bugs were harder to
notice because of timeouts. I'm against entrenching this stuff further.

Greetings,

Andres Freund