Two Index Questions
От | Josh Berkus |
---|---|
Тема | Two Index Questions |
Дата | |
Msg-id | 200207190933.59283.josh@agliodbs.com обсуждение исходный текст |
Ответы |
Re: Two Index Questions
Re: Two Index Questions |
Список | pgsql-sql |
Folks (esp. Tom, Stephan, and Bruce): I have two questions for my "Adventures in PostgreSQL" article reasearch: Multi-Column Indexes and GROUP BY: Q: If you group a table by multiple colums, e.g.SELECT t1.A, t1.B, t1.C, MAX(t1.G)FROM t1GROUP BY t1.A, t1.B, t1.C Thenwould a multi-column index on A, B, C be faster than seperate indexes on A, B and C? I've run a few tests, but I don't have enough data in the seperate tables to really get a feel for the difference. DESC Alpha Sort Indexes: Q: In PostgreSQL 7.0, there was an issue that indexes where never consulted for DESC alpha sorts. Has this been resolved? If so, does one need to create any special indexes to take advantage of indexes for DESC sorts? Thanks for your help! -- -Josh BerkusAglio Database SolutionsSan Francisco
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