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From: Pavel Stehule <pavel.stehule@gmail.com>
To: Arthur Zakirov <a.zakirov@postgrespro.ru>
Cc: PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: [HACKERS] proposal: schema variables
Date: Tue, 17 Apr 2018 18:28:19 +0200
Message-ID: <CAFj8pRD3RGW7zoHs2-4FgUKnV7TmHYbZiQYq1KS+KgwS3W30bQ@mail.gmail.com> (raw)
In-Reply-To: <20180417141410.GA7917@zakirov.localdomain>
References: <CAFj8pRDY+m9OOxfO10R7J0PAkCCauM-TweaTrdsrsLGMb1VbEQ@mail.gmail.com>
	<20180417141410.GA7917@zakirov.localdomain>

Hi

2018-04-17 16:14 GMT+02:00 Arthur Zakirov <a.zakirov@postgrespro.ru>:

> Hello Pavel,
>
> On Thu, Oct 26, 2017 at 09:21:24AM +0200, Pavel Stehule wrote:
> > I hope so this proposal is good enough and simple.
> >
> > Comments, notes?
>
> As I understood variables are stored in pg_class table. Did you consider
> storing variables in a special catalog table? It can be named as
> pg_variable.
>
> pg_variable table requires more code of course, but it would fix the
> issues:
> - pg_class has a lot attributes which are not related with variables,
>   and I think variables don't need many of them
> - in a future variables might want to have some additional attributes
>   which are not needed for relations, you can easily add them to
>   pg_variable
>
> What do you think?
>

I though about it, and I am inclined to prefer pg_class instead separate
tables.

It true, so there are lot of "unused" attributes for this purpose, but
there is lot of shared attributes, and lot of shared code. Semantically, I
see variables in family of sequences, tables, indexes, views. Now, it
shares code, and I hope in next steps more code can be shared -
constraints, triggers.

There are two objective arguments for using pg_class:

1. unique name in schema - it reduces risk of collisions
2. sharing lot of code

So in this case I don't see well benefits of separate table.

Regards

Pavel



>
> --
> Arthur Zakirov
> Postgres Professional: http://www.postgrespro.com
> Russian Postgres Company
>

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