Re: Seq scan with a like operator
От | Jouneau Luc |
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Тема | Re: Seq scan with a like operator |
Дата | |
Msg-id | 011e01c470c9$26b637f0$4703668a@pc502jlo обсуждение исходный текст |
Ответ на | Seq scan with a like operator ("Jouneau Luc" <Luc.Jouneau@diamant.jouy.inra.fr>) |
Ответы |
Re: Seq scan with a like operator
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Список | pgsql-admin |
> LIKE requires a different kind of index. See > <http://www.postgresql.org/docs/7.4/static/indexes-opclass.html>. Thanks for the answer peter, I didn't notice it when I red the doc, but if I create the index as specified then it is the query with equal operator which use a seq scan. Do I have to create 2 indexes on the same column (with different datatype) in order to support different kind of queries ? Well, It seems quite strange to me : Suppose you have an user interface in which user can parameter his query on 4 varchar fields (independantly, i.e field 4 does not need to have field 1,2 or 3 filled), and you allow to use generic character such as '*' or '?' (which will be translated into '%' and '_'). User can also fill in exact values. Then you would have to create 4*2=8 indexes to handle every combinations of possible queries. It would also mean that support both exact generic queries double the indexing task on update/insert/delete. Am I wrong ? Luc Jouneau
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