Re: Indexes with descending date columns
От | Theo Kramer |
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Тема | Re: Indexes with descending date columns |
Дата | |
Msg-id | 1143174749.2820.2.camel@josh обсуждение исходный текст |
Ответ на | Re: Indexes with descending date columns (andrew@pillette.com) |
Ответы |
Re: Indexes with descending date columns
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Список | pgsql-performance |
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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