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help / color / mirror / Atom feedFrom: Pavel Luzanov <p.luzanov@postgrespro.ru>
To: Pavel Stehule <pavel.stehule@gmail.com>
Cc: David G. Johnston <david.g.johnston@gmail.com>
Cc: Pavel Golub <pavel@gf.microolap.com>
Cc: PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: [HACKERS] proposal: schema variables
Date: Mon, 12 Mar 2018 18:38:39 +0300
Message-ID: <ef39f19b-9d5c-78d1-6afa-adbe1288a20b@postgrespro.ru> (raw)
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On 12.03.2018 09:54, Pavel Stehule wrote:
>
> 2018-03-12 7:49 GMT+01:00 Pavel Luzanov <p.luzanov@postgrespro.ru
> <mailto:p.luzanov@postgrespro.ru>>:
>
>
> Is there any chances that it will work on replicas?
>
> ...
>
> sure, it should to work. Now, I am try to solve a issues on concept
> level - the LET code is based on DML code base, so probably there is
> check for rw transactions. But it is useless for LET command.
Very, very good!
As I understand, the work on this patch now in progress and it not in
commitfest.
Please explain what features of schema variables I can review now.
From first post of this thread the syntax of the CREATE VARIABLE command:
CREATE [TEMP] VARIABLE [IF NOT EXISTS] name AS type
[ DEFAULT expression ] [[NOT] NULL]
[ ON TRANSACTION END { RESET | DROP } ]
[ { VOLATILE | STABLE } ];
But in psql I see only:
\h create variable
Command: CREATE VARIABLE
Description: define a new permissioned typed schema variable
Syntax:
CREATE VARIABLE [ IF NOT EXISTS ] name [ AS ] data_type ]
I can include DEFAULT clause in CREATE VARIABLE command, but the value
not used:
postgres=# create variable i int default 0;
CREATE VARIABLE
postgres=# select i;
i
---
(1 row)
postgres=# \d+ i
schema variable "public.i"
Column | Type | Storage
--------+---------+---------
i | integer | plain
BTW, I found an error in handling of table aliases:
postgres=# create variable x text;
CREATE VARIABLE
postgres=# select * from pg_class AS x where x.relname = 'x';
ERROR: type text is not composite
It thinks that x.relname is an attribute of x variable instead of an
alias for pg_class table.
-----
Pavel Luzanov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
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To: pgsql-performance@postgresql.org
Cc: p.luzanov@postgrespro.ru, pavel.stehule@gmail.com, david.g.johnston@gmail.com, pavel@gf.microolap.com, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] proposal: schema variables
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