Re: [HACKERS] More stats about skipped vacuums

At Thu, 08 Feb 2018 18:04:15 +0900 (Tokyo Standard Time), Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp> wrote in
<20180208.180415.112312013.horiguchi.kyotaro@lab.ntt.co.jp>
> > > I suggest we remove support for dynamic_shared_memory_type = none first,
> > > and see if we get any complaints.  If we don't, then future patches can
> > > rely on it being present.
> > 
> > If we remove it in v11, it'd still be maybe a year from now before we'd
> > have much confidence from that alone that nobody cares.  I think the lack
> > of complaints about it in 9.6 and 10 is a more useful data point.
> 
> So that means that we are assumed to be able to rely on the
> existence of DSM at the present since over a year we had no
> complain despite the fact that DSM is silently turned on? And
> apart from that we are ready to remove 'none' from the options of
> dynamic_shared_memory_type right now?

I found the follwoing commit related to this.

| commit d41ab71712a4457ed39d5471b23949872ac91def
| Author: Robert Haas <rhaas@postgresql.org>
| Date:   Wed Oct 16 09:41:03 2013 -0400
| 
|     initdb: Suppress dynamic shared memory when probing for max_connections.
|     
|     This might not be the right long-term solution here, but it will
|     hopefully turn the buildfarm green again.
|     
|     Oversight noted by Andres Freund

The discussion is found here.

https://www.postgresql.org/message-id/CA+TgmoYHiiGrcvSSJhmbSEBMoF2zX_9_9rWd75Cwvu99YrDxew@mail.gmail.com

I suppose that the problem has not been resolved yet..

regards,

-- 
Kyotaro Horiguchi
NTT Open Source Software Center