From: | Andres Freund <andres(at)2ndquadrant(dot)com> |
---|---|
To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
Cc: | Satoshi Nagayasu <snaga(at)uptime(dot)jp>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Josh Berkus <josh(at)agliodbs(dot)com>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>, Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, Jim Nasby <jim(at)nasby(dot)net>, Greg Stark <stark(at)mit(dot)edu>, Hannu Krosing <hannu(at)2ndquadrant(dot)com>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: pg_system_identifier() |
Date: | 2013-09-17 14:59:59 |
Message-ID: | 20130917145959.GL5452@awork2.anarazel.de |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On 2013-09-17 10:57:46 -0400, Robert Haas wrote:
> On Mon, Sep 16, 2013 at 1:25 AM, Satoshi Nagayasu <snaga(at)uptime(dot)jp> wrote:
> > How about adding new system view with new function which returns
> > a single pg_controldata value in text type, and using a cast for
> > each column in the view definition?
> >
> > CREATE VIEW pg_catalog.pg_controldata AS
> > SELECT pg_controldata('control_version')::integer AS control_version,
> > pg_controldata('catalog_version')::integer AS catalog_version,
> > pg_controldata('system_identifier')::bigint AS system_identifier,
> > ...
> > pg_controldata('next_xlog_file')::char(25) AS next_xlog_file,
> > ...
> > pg_controldata('encoding')::text AS encoding;
> >
> > Given that the view can work like a SRF, and it allows us to retrieve
> > all the values of pg_controldata with appropriate types in single
> > record from the view:
>
> I like this idea. I think having an easy way to get the values with
> the right types will be a plus. But adding a separate function for
> each field seems excessive, so I think this is a good compromise.
Why not add a single function returning a composite type then? That'd at
least have a chance of returning consistent values for the individual
values that change during runtime. It would also produce proper errors
when you load a view using columns that don't exist anymore instead of
just at runtime.
Greetings,
Andres Freund
--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
From | Date | Subject | |
---|---|---|---|
Next Message | Alvaro Herrera | 2013-09-17 15:00:17 | Re: proposal: simple date constructor from numeric values |
Previous Message | Robert Haas | 2013-09-17 14:57:46 | Re: pg_system_identifier() |