From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Jürgen Purtz <juergen@purtz.de>
Cc: Erik Rijkers <er@xs4all.nl>
Cc: Laurenz Albe <laurenz.albe@cybertec.at>
Cc: Fabien COELHO <coelho@cri.ensmp.fr>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Cc: Corey Huinker <corey.huinker@gmail.com>
Cc: Justin Pryzby <pryzby@telsasoft.com>
Cc: Roger Harkavy <rogerharkavy@gmail.com>
Cc: pgsql-hackers@postgresql.org, Michael Paquier <michael@paquier.xyz>
Subject: Re: Add A Glossary
Date: Sun, 17 May 2020 02:51:26 -0400
Message-ID: <20200517065126.GA20730@alvherre.pgsql> (raw)
In-Reply-To: <774bb48d-cd3d-17ee-77e9-937519bf9c6e@purtz.de>
On 2020-May-17, Jürgen Purtz wrote:
> On 15.05.20 02:00, Alvaro Herrera wrote:
> > Thanks everybody. I have compiled together all the suggestions and the
> > result is in the attached patch. Some of it is of my own devising.
> >
> > * I changed "instance", and made "cluster" be mostly a synonym of that.
> In my understanding, "instance" and "cluster" should be different things,
> not only synonyms. "instance" can be the term for permanently fluctuating
> objects (processes and RAM) and "cluster" can denote the more static objects
> (directories and files). What do you think? If you agree, I would create a
> patch.
I don't think that's the general understanding of those terms. For all
I know, they *are* synonyms, and there's no specific term for "the
fluctuating objects" as you call them. The instance is either running
(in which case there are processes and RAM) or it isn't.
> > * I removed "global SQL object" and made "SQL object" explain it.
> +1., but see the (huge) different spellings in patch.
This seems a misunderstanding of what "local" means. Any object that
exists in a database is local, regardless of whether it exists in a
schema or not. "Extensions" is one type of object that does not belong
in a schema. "Foreign data wrapper" is another type of object that does
not belong in a schema. Same with data type casts. They are *not*
global objects.
> bloat: changed 'current row' to 'relevant row' because not only the youngest
> one is relevant (non-bloat).
Hm. TBH I'm not sure of this term at all. I think we sometimes use the
term "bloat" to talk about the dead rows only, ignoring the free space.
> data type casts: Are you sure that they are global? In pg_cast 'relisshared'
> is 'false'.
I'm not saying they're global. I'm saying they're outside schemas.
Maybe this definition needs more rewording, if this bit is unclear.
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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To: pgsql-hackers@postgresql.org
Cc: alvherre@2ndquadrant.com, juergen@purtz.de, er@xs4all.nl, laurenz.albe@cybertec.at, coelho@cri.ensmp.fr, peter.eisentraut@2ndquadrant.com, corey.huinker@gmail.com, pryzby@telsasoft.com, rogerharkavy@gmail.com, michael@paquier.xyz
Subject: Re: Add A Glossary
In-Reply-To: <20200517065126.GA20730@alvherre.pgsql>
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