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help / color / mirror / Atom feedFrom: Gilles Darold <gilles.darold@dalibo.com>
To: pgsql-hackers@postgresql.org
Subject: Re: proposal: schema variables
Date: Tue, 31 Oct 2017 23:36:53 +0100
Message-ID: <9f1f9d20-e913-82fb-c654-ae8c07537fee@dalibo.com> (raw)
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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?
--
Gilles Darold
Consultant PostgreSQL
http://dalibo.com - http://dalibo.org
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To: pgsql-performance@postgresql.org
Cc: gilles.darold@dalibo.com, pgsql-hackers@postgresql.org
Subject: Re: proposal: schema variables
In-Reply-To: <9f1f9d20-e913-82fb-c654-ae8c07537fee@dalibo.com>
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