Re: Upgrading to 7.2
От | Marc Lavergne |
---|---|
Тема | Re: Upgrading to 7.2 |
Дата | |
Msg-id | 3C6BF8D5.8060302@richlava.com обсуждение исходный текст |
Ответ на | Upgrading to 7.2 (Chris Field <cfields@affinitysolutions.com>) |
Список | pgsql-hackers |
I have that book too (page 168 in my revision) definitely looks like an error. Indexes cannot be applied to aggregate functions since the data rowset is only defined in the context of a given query. So, until functionality is added to maintain an index based on a SQL query (view or what not) rather than a table, this just ain't gonna happen. :) Chris Field wrote: > Thanks for responding, I am thinking it might be fairly beneficial to > upgrade. > > >>Ummm, max() is an aggregate function, how can you create an index on >>it? >> > > In the postgresSQL Essential Reference by Barry Stinson it specifically > has a index topic on functional indexes, with the given example being > " CREATE INDEX max_payroll_idx ON payroll (MAX(salary)); " > so either the book was a waste of money, or this is a 7.2 specific > feature. > > -- 01010101010101010101010101010101010101010101010101 Marc P. Lavergne [wk:650-576-7978 hm:407-648-6996] Senior Software Developer Global Knowledge Management Worldwide Support Technologies Openwave Systems Inc. -- "Anyone who slaps a 'this page is best viewed with Browser X' label on a Web page appears to be yearning for the bad old days, before the Web, when you had very little chance of reading a document written on another computer, another word processor, or another network." -Tim Berners-Lee (Technology Review, July 1996) 01010101010101010101010101010101010101010101010101
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