Re: Fwd: Index on table when using DESC clause - Mailing list pgsql-performance

From Oleg Bartunov
Subject Re: Fwd: Index on table when using DESC clause
Date
Msg-id Pine.GSO.4.62.0505232345390.2767@ra.sai.msu.su
Whole thread Raw
In response to Re: Fwd: Index on table when using DESC clause  (Yves Vindevogel <yves.vindevogel@implements.be>)
List pgsql-performance
You didn't say what version of PostgreSQL you're trying.
I recall old version doesn't used index for backward pagination.

Oleg

On Mon, 23 May 2005, Yves Vindevogel wrote:

> I tried that, but
>
> create index ixTest on table1 (pages desc, documentname)
>
> gives me a syntax error
>
>
> On 23 May 2005, at 20:03, Steinar H. Gunderson wrote:
>
>> On Mon, May 23, 2005 at 07:41:19PM +0200, Yves Vindevogel wrote:
>>> However, when I query my db using for instance   order by pages,
>>> documentname, it is very fast.
>>> If I use   order by pages desc, documentname, it is not fast at
>>> all, like it is not using the index properly at all.
>>
>> Make an index on "pages desc, documentname asc".
>>
>> /* Steinar */
>> --
>> Homepage: http://www.sesse.net/
>>
>> ---------------------------(end of broadcast)---------------------------
>> TIP 9: the planner will ignore your desire to choose an index scan if your
>>       joining column's datatypes do not match
>>
>>
> Met vriendelijke groeten,
> Bien ? vous,
> Kind regards,
>
> Yves Vindevogel
> Implements
>
>

     Regards,
         Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83

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