Re: Fwd: Index on table when using DESC clause
От | Oleg Bartunov |
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Тема | Re: Fwd: Index on table when using DESC clause |
Дата | |
Msg-id | Pine.GSO.4.62.0505232345390.2767@ra.sai.msu.su обсуждение исходный текст |
Ответ на | Re: Fwd: Index on table when using DESC clause (Yves Vindevogel <yves.vindevogel@implements.be>) |
Список | 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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