Message-ID: <d42b3336db9a6b1cb8f4f1cee947673bf77d3a36.camel@cybertec.at>
Subject: Re: Shrinking SVG (Again)
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: =?ISO-8859-1?Q?J=FCrgen?= Purtz <juergen@purtz.de>,
	pgsql-docs@lists.postgresql.org
Date: Wed, 15 Jan 2020 23:25:00 +0100
In-Reply-To: <1246dec7-7426-6d5c-94a0-13ecd052b9fc@purtz.de>
References: <af4a422b-b456-f381-a3f1-321e9ba805bb@purtz.de>
	 <1246dec7-7426-6d5c-94a0-13ecd052b9fc@purtz.de>
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On Wed, 2020-01-15 at 14:56 +0100, Jürgen Purtz wrote:
> I plan to deliver 3 more graphics, see attachment. When creating their 
> textual description in the SGML files I faced a problems: The patch of 
> GSoD 
> https://www.postgresql.org/message-id/flat/CAEkD-mBFQb61gHNWR0cN5K4G4q-i1PRwNn_OKVkKSaaJa5_LbA%40mail.gmail.com#67104a6097e63371c527b14ff43ddafb 
> is not yet committed. But this chapter is a good place for the graphics. 
> Will the GSoD patch become part of the documentation?

Both Tom and me showed interest, and the feedback was that some things
could be improved.  I have not heard back from the author since;
I hope she didn't get discouraged.

There were definitely some things there that shouldn't go to waste.

> Any comments? Errors in the graphics? Suggestions? What's about the GSoD 
> patch?

I particularly like the first image with the memory and process architecture.

Some mistakes:

- wal_buffers is shared memory, but it is not a part of shared_buffers

- The process that performs most of the writes to the data files is
  the checkpointer.  Sometimes backends also have to write to data
  files.

Minor quibbles:

- The "server process" is traditionally called "backend process"

- "Special purpose memory" is strange.
  I thing "private memory" would be better.
  I don't know how it could be depicted that each of the backends
  has his own.

I liked the "cluster / database / schema" image less.

Some problems:

- No user data should be stored in the "postgres" database.

- "template0" has *no* other schemas or tables.
  It must be absolutely empty.

- I am missing the global objects like roles and tablespaces
  "outside" the databases.

I am fine with the directory layout image, but I wonder what
"fluctuating states" may be.


Yours,
Laurenz Albe