public inbox for pgsql-performance@postgresql.org
help / color / mirror / Atom feedFrom: Gilles Darold <gilles.darold@dalibo.com>
To: pgsql-hackers@postgresql.org
Subject: Re: proposal: schema variables
Date: Wed, 1 Nov 2017 00:02:26 +0100
Message-ID: <c48dc141-776e-2284-15fa-3863f7b6a1b4@dalibo.com> (raw)
In-Reply-To: <9f1f9d20-e913-82fb-c654-ae8c07537fee@dalibo.com>
References: <CAFj8pRDY+m9OOxfO10R7J0PAkCCauM-TweaTrdsrsLGMb1VbEQ@mail.gmail.com>
<20171026220732.GI4496@localhost>
<CAFj8pRAemkdaDuoRQzrhs2GU59Bb_yHuquJC6nyrwGHfVdLuLw@mail.gmail.com>
<1509399760322-0.post@n3.nabble.com>
<CAFj8pRC3jq38zpNRJjQepkQKogfKC=0teb4OviZ7RwZ4je8ymQ@mail.gmail.com>
<5665be80-1772-4998-8dbc-3bd071c0d9ad@rielau.com>
<CAFj8pRB9YEzD_-qno8Y2Xj08f4gu2LYJFBd1QDW82EKPW-vmsQ@mail.gmail.com>
<1509485317393-0.post@n3.nabble.com>
<9f1f9d20-e913-82fb-c654-ae8c07537fee@dalibo.com>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-hackers>
Le 31/10/2017 à 23:36, Gilles Darold a écrit :
> Le 31/10/2017 à 22:28, srielau a écrit :
>> Pavel,
>>
>> There is no
>> DECLARE TEMP CURSOR
>> or
>> DECLARE TEMP variable in PLpgSQL
>> and
>> CREATE TEMP TABLE has a different meaning from what I understand you
>> envision for variables.
>>
>> But maybe I'm mistaken. Your original post did not describe the entire
>> syntax:
>> CREATE [TEMP] VARIABLE [IF NOT EXISTS] name AS type
>> [ DEFAULT expression ] [[NOT] NULL]
>> [ ON TRANSACTION END { RESET | DROP } ]
>> [ { VOLATILE | STABLE } ];
>>
>> Especially the TEMP is not spelled out and how its presence affects or
>> doesn't ON TRANSACTION END.
>> So may be if you elaborate I understand where you are coming from.
> I think that the TEMP keyword can be removed. If I understand well the
> default scope for variable is the session, every transaction in a
> session will see the same value. For the transaction level, probably the
> reason of the TEMP keyword, I think the [ ON TRANSACTION END { RESET |
> DROP } ] will allow to restrict the scope to this transaction level
> without needing the TEMP keyword. When a variable is created in a
> transaction, it is temporary if "ON TRANSACTION END DROP" is used
> otherwise it will persist after the transaction end. I guess that this
> is the same as using TEMP keyword?
I forgot to say that in the last case the DECLARE statement can be used
so I don't see the reason of this kind of "temporary" variables.
Maybe the variable object like used in DB2 and defined in document :
https://www.ibm.com/support/knowledgecenter/en/SSEPEK_11.0.0/sqlref/src/tpc/db2z_sql_createvariable....
could be enough to cover our needs.
--
Gilles Darold
Consultant PostgreSQL
http://dalibo.com - http://dalibo.org
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
reply
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: gilles.darold@dalibo.com, pgsql-hackers@postgresql.org
Subject: Re: proposal: schema variables
In-Reply-To: <c48dc141-776e-2284-15fa-3863f7b6a1b4@dalibo.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox