Date: Tue, 5 Apr 2022 20:22:01 -0700
From: Andres Freund <andres@anarazel.de>
To: Greg Stark <stark@mit.edu>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>,
	Melanie Plageman <melanieplageman@gmail.com>,
	Justin Pryzby <pryzby@telsasoft.com>,
	Thomas Munro <thomas.munro@gmail.com>,
	"David G. Johnston" <david.g.johnston@gmail.com>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: shared-memory based stats collector - v70
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Hi,

On 2022-04-05 23:11:07 -0400, Greg Stark wrote:
> I've never tried to review a 24-patch series before. It's kind of
> intimidating.... Is there a good place to start to get a good idea of
> the most important changes?

It was more at some point :). And believe me, I find this whole project
intimidating and exhausting. The stats collector is entangled in a lot of
places, and there was a lot of preparatory work to get this point.

Most of the commits aren't really interesting, I broke them out to make the
"main commit" a bit smaller, because it's exhausting to look at a *huge*
single commit. I wish I could have broken it down more, but I didn't find a
good way.

The interesting commit is
v70-0010-pgstat-store-statistics-in-shared-memory.patch
which actually replaces the stats collector by storing stats in shared
memory. It contains a, now hopefully decent, overview of how things work at
the top of pgstat.c.

Greetings,

Andres Freund