Re: problem with max and not using index on PK
От | pginfo |
---|---|
Тема | Re: problem with max and not using index on PK |
Дата | |
Msg-id | 3EB3B7E0.5E6030AE@t1.unisoftbg.com обсуждение исходный текст |
Ответ на | Re: problem with max and not using index on PK (Philip Warner <pjw@rhyme.com.au>) |
Список | pgsql-sql |
It is working in this case. I see that using "order by" make the query slower by 25% if I start it on another column. Alse as I wrote in oracle the max use indexes. regards, ivan. Philip Warner wrote: > At 11:12 AM 3/05/2003 +0200, pginfo wrote: > >I do not know the reason for not using index in this case. > > PostgreSQL does not know that it can use the index, and the query example > you gave is about the only case in which it can use the index. You can get > it to use an index by rewriting it as: > > select IDS from t_sk10 order by IDS desc limit 1; > > ...nowhere near as nice, but it works. > > ---------------------------------------------------------------- > Philip Warner | __---_____ > Albatross Consulting Pty. Ltd. |----/ - \ > (A.B.N. 75 008 659 498) | /(@) ______---_ > Tel: (+61) 0500 83 82 81 | _________ \ > Fax: (+61) 03 5330 3172 | ___________ | > Http://www.rhyme.com.au | / \| > | --________-- > PGP key available upon request, | / > and from pgp5.ai.mit.edu:11371 |/
В списке pgsql-sql по дате отправления: