Re: Indexes with descending date columns

From: Alvaro Herrera
Subject: Re: Indexes with descending date columns
Date: ,
Msg-id: 20060323132448.GB4881@surnet.cl
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In response to: Re: Indexes with descending date columns  (Theo Kramer)
Responses: Array performance  (Ruben Rubio Rey)
List: pgsql-performance

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Indexes with descending date columns  (Theo Kramer, )
 Re: Indexes with descending date columns  (, )
  Re: Indexes with descending date columns  (Theo Kramer, )
   Re: Indexes with descending date columns  (Alvaro Herrera, )
    Array performance  (Ruben Rubio Rey, )
     Re: Array performance  ("Jim C. Nasby", )
      Re: Array performance  (Ruben Rubio Rey, )
       Re: Array performance  ("Jim C. Nasby", )
        Re: Array performance  (Michael Fuhr, )
         limitation using LIKE on ANY(array)  (K C Lau, )
          Re: limitation using LIKE on ANY(array)  (Tom Lane, )
           Re: limitation using LIKE on ANY(array)  (K C Lau, )
     Re: Array performance  (Tom Lane, )
      Re: Array performance  (Ruben Rubio Rey, )
   Re: Indexes with descending date columns  ("Jim C. Nasby", )
    Re: Indexes with descending date columns  (Theo Kramer, )
     Re: Indexes with descending date columns  ("Jim C. Nasby", )
      Re: Indexes with descending date columns  (Bruce Momjian, )
       Re: Indexes with descending date columns  (Markus Schaber, )
  Re: Indexes with descending date columns  (Theo Kramer, )
   Re: Indexes with descending date columns  (Tom Lane, )

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.

--
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.


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