From: solarsail <solarsail@gmail.com>
To: Yasir Malik <ymalik@cs.stevens.edu>
Cc: PostgreSQL <pgsql-sql@postgresql.org>
Subject: Re: using pg_tables and tablename in queries
Date: Tue, 4 Oct 2005 15:50:39 -0400
Message-ID: <aa44f4a30510041250k3ea4e067r424d66ae2461453@mail.gmail.com> (raw)
In-Reply-To: <Pine.NEB.4.62.0510041518300.20189@long-trail.cs.stevens-tech.edu>
References: <aa44f4a30510040930m510bbe8do4babd97b1b37c90d@mail.gmail.com>
<9420.1128445291@sss.pgh.pa.us>
<aa44f4a30510041140s1f552a78yfa44cb287144ad2b@mail.gmail.com>
<Pine.NEB.4.62.0510041518300.20189@long-trail.cs.stevens-tech.edu>
I managed to make this work as sub query before... I wish I had
written it down somewhere...
Regarding the creation of a function. I do have a function that
almost does that. I'm having a hard time getting it to return a set
of records from the EXECUTE command ( more than one row returned by
the select * ...).
If I generate a temporary table instead of returning the results how
long will that table exist for? Excuse the OOP terminology but would
it be correct to create a 'Singleton' to access the temporary table,
where if it exists and is less than 30 minutes old use that one,
otherwise drop the table and recreate it?
Thanks
-- sample function..
CREATE OR REPLACE FUNCTION testfunc_jointables()
RETURNS SETOF record AS
$BODY$
DECLARE
query TEXT;
BEGIN
query := 'auditrecord';
FOR
atablename IN select * from pg_tables where tablename like 'mytable_%'
LOOP
query := query || ', ' || quote_ident(atablename.tablename);
END LOOP;
EXECUTE ' SELECT * from ' || query;
END;
On 10/4/05, Yasir Malik <ymalik@cs.stevens.edu> wrote:
> > The current behavior is by design.
> >
> > We use the table as a logging repository. It can get very large 250 000
> > records. Because of the large number of records that we have in the table we
> > found it was much faster to perform inserts on a smaller table. Our current
> > system rolls the tables over every 12 hours or so, creating a new table with
> > the following behavior:
> >
> > CREATE TABLE mytable_temp {...}
> >
> > ALTER TABLE mytable RENAME TO mytable_back_datetime;
> > ALTER TABLE mytable_temp RENAME TO mytable;
> >
> > I want to join the mytable_back_datetime tables together in order to perform
> > queries against my huge set of data to generate some reports. I'm probably
> > going to create a temporary table with a few indexes to make the reports run
> > faster... however I need to join the tables all together first.
> >
>
> I would create a function that creates a string with a query that includes
> all the tables you need, and call execute on the string. You would loop
> through the all tables from pg_tables and keep on appending the table name
> you need.
>
> Regards,
> Yasir
>
> ---------------------------(end of broadcast)---------------------------
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>
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>
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To: pgsql-sql@postgresql.org
Cc: solarsail@gmail.com, ymalik@cs.stevens.edu
Subject: Re: using pg_tables and tablename in queries
In-Reply-To: <aa44f4a30510041250k3ea4e067r424d66ae2461453@mail.gmail.com>
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