Re: Reducing pg_ctl's reaction time

On 2017-06-26 17:38:03 -0400, Tom Lane wrote:
> Andres Freund <andres(at)anarazel(dot)de> writes:
> > On 2017-06-26 17:30:30 -0400, Tom Lane wrote:
> >> No, I don't like that at all. Has race conditions against updates
> >> coming from the startup process.
>
> > You'd obviously have to take the appropriate locks. I think the issue
> > here is less race conditions, and more that architecturally we'd
> > interact with shmem too much.
>
> Uh, we are *not* taking any locks in the postmaster.

I'm not sure why you're 'Uh'ing, when my my point pretty much is that we
do not want to do so?

> Hm. Take that a bit further, and we could drop the connection probes
> altogether --- just put the whole responsibility on the postmaster to
> show in the pidfile whether it's ready for connections or not.

Yea, that seems quite appealing, both from an architectural, simplicity,
and log noise perspective. I wonder if there's some added reliability by
the connection probe though? Essentially wondering if it'd be worthwhile
to keep a single connection test at the end. I'm somewhat disinclined
though.

- Andres