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In-Reply-To: <Z4p41KpSENxS0ASL@momjian.us>
From: Pavel Stehule <pavel.stehule@gmail.com>
Date: Fri, 17 Jan 2025 16:55:07 +0100
Message-ID: 
 <CAFj8pRCJFQ0UQzZoJRdxv51Vst_emnXMbZtWNv0HTWzeZ0j9Eg@mail.gmail.com>
Subject: Re: Fwd: Re: proposal: schema variables
To: Bruce Momjian <bruce@momjian.us>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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p=C3=A1 17. 1. 2025 v 16:35 odes=C3=ADlatel Bruce Momjian <bruce@momjian.us=
> napsal:

> On Fri, Jan 17, 2025 at 04:32:07PM +0100, Pavel Stehule wrote:
> > This discussion was around 2017 when I wrote a proposal and I hadn't a
> feeling
>
> 2017 is seven years ago so it would be good to get current feedback on
> the desirability of this feature.
>
> > There is one stronger argument for session variables - we are missing
> global
> > temporary tables. It is a real
> > limit and more times I found users with bloated pg_class, pg_attributes
> due
> > using temp tables. I don't believe
> > so we can have a global temp table - it is a significantly more
> difficult task
> > than session variables. At the end
> > session variables are trivial against global temp tables, and can repla=
ce
> > global temp tables in some use cases.
> > And the solution can be nicer, cleaner, safer than with a workaround
> based on
> > GUC.
>
> So this feature would be like global GUC variables, with permission
> control?
>

+ types and domain type check - holds data in binary form - there are not
conversions binary, text
+ it is declared - so less space for misuse is there. Custom GUC are
absolutely tolerant
+ it is a fully database object, only owner can alter it,  and event
triggers are supported, sinval
+ possibility to set mutability, default value

Regards

Pavel


>
> --
>   Bruce Momjian  <bruce@momjian.us>        https://momjian.us
>   EDB                                      https://enterprisedb.com
>
>   Do not let urgent matters crowd out time for investment in the future.
>
>
>

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<div dir=3D"ltr"><div dir=3D"ltr"><br></div><br><div class=3D"gmail_quote g=
mail_quote_container"><div dir=3D"ltr" class=3D"gmail_attr">p=C3=A1 17. 1. =
2025 v=C2=A016:35 odes=C3=ADlatel Bruce Momjian &lt;<a href=3D"mailto:bruce=
@momjian.us">bruce@momjian.us</a>&gt; napsal:<br></div><blockquote class=3D=
"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(2=
04,204,204);padding-left:1ex">On Fri, Jan 17, 2025 at 04:32:07PM +0100, Pav=
el Stehule wrote:<br>
&gt; This discussion was around 2017 when I wrote a proposal and I hadn&#39=
;t a feeling<br>
<br>
2017 is seven years ago so it would be good to get current feedback on<br>
the desirability of this feature.<br>
<br>
&gt; There is one stronger argument for session variables - we are missing =
global<br>
&gt; temporary tables. It is a real<br>
&gt; limit and more times I found users with bloated pg_class, pg_attribute=
s due<br>
&gt; using temp tables. I don&#39;t believe<br>
&gt; so we can have a global temp table - it is a significantly more diffic=
ult task<br>
&gt; than session variables. At the end<br>
&gt; session variables are trivial against global temp tables, and can repl=
ace<br>
&gt; global temp tables in some use cases.<br>
&gt; And the solution can be nicer, cleaner, safer than with a workaround b=
ased on<br>
&gt; GUC.<br>
<br>
So this feature would be like global GUC variables, with permission<br>
control?<br></blockquote><div><br></div>+ types and domain type check - hol=
ds data in binary form - there are not conversions binary, text<br></div><d=
iv class=3D"gmail_quote gmail_quote_container">+ it is declared - so less s=
pace for misuse is there. Custom GUC are absolutely tolerant<br></div><div =
class=3D"gmail_quote gmail_quote_container">+ it is a fully database object=
, only owner can alter it,=C2=A0 and event triggers are supported, sinval</=
div><div class=3D"gmail_quote gmail_quote_container">+ possibility to set m=
utability, default value<br></div><div class=3D"gmail_quote gmail_quote_con=
tainer"><br></div><div class=3D"gmail_quote gmail_quote_container">Regards<=
/div><div class=3D"gmail_quote gmail_quote_container"><br></div><div class=
=3D"gmail_quote gmail_quote_container">Pavel<br></div><div class=3D"gmail_q=
uote gmail_quote_container"><br></div><div class=3D"gmail_quote gmail_quote=
_container"><div>=C2=A0<br></div><blockquote class=3D"gmail_quote" style=3D=
"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-le=
ft:1ex">
<br>
-- <br>
=C2=A0 Bruce Momjian=C2=A0 &lt;<a href=3D"mailto:bruce@momjian.us" target=
=3D"_blank">bruce@momjian.us</a>&gt;=C2=A0 =C2=A0 =C2=A0 =C2=A0 <a href=3D"=
https://momjian.us" rel=3D"noreferrer" target=3D"_blank">https://momjian.us=
</a><br>
=C2=A0 EDB=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 <a hr=
ef=3D"https://enterprisedb.com" rel=3D"noreferrer" target=3D"_blank">https:=
//enterprisedb.com</a><br>
<br>
=C2=A0 Do not let urgent matters crowd out time for investment in the futur=
e.<br>
<br>
<br>
</blockquote></div></div>

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