From: Theo Kramer <theo@flame.co.za>
To: pgsql-performance@postgresql.org
Subject: Re: Indexes with descending date columns
Date: Fri, 24 Mar 2006 06:32:29 +0200
Message-ID: <1143174749.2820.2.camel@josh> (raw)
In-Reply-To: <20060323141622.GC4881@surnet.cl>
References: <200603170625.k2H6PJ926955@pillette.com>
<1143112188.2810.27.camel@theo-laptop.int.coza.net.za>
<20060323141622.GC4881@surnet.cl>
On Thu, 2006-03-23 at 16:16, Alvaro Herrera wrote:
> Theo Kramer wrote:
>
> > All good input - thanks, however, before I start messing with my stuff
> > which I know will be complex - some questions to any of the developers
> > on the list.
> >
> > i Is it feasible to extend index creation to support descending
> > columns? ... this is supported on other commercial and non
> > commercial databases, but I do not know if this is a SQL standard.
>
> This can be done. You need to create an operator class which specifies
> the reverse sort order (i.e. reverse the operators), and then use it in
> the new index.
Hmmm, would that then result in the following syntax being valid?
create index my_idx on my_table (c1, c2 desc, c3, c4 desc) ;
where my_table is defined as
create table my_table (
c1 text,
c2 timestamp,
c3 integer,
c4 integer
);
If so, I would appreciate any pointers on where to start on this -
already fumbling my way through Interfacing Extensions To Indexes in the
manual...
Regards
Theo
--
Regards
Theo
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To: pgsql-performance@postgresql.org
Cc: theo@flame.co.za
Subject: Re: Indexes with descending date columns
In-Reply-To: <1143174749.2820.2.camel@josh>
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