Re: Rules/Trigges Trade-offs
От | Josh Berkus |
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Тема | Re: Rules/Trigges Trade-offs |
Дата | |
Msg-id | 200212061554.07415.josh@agliodbs.com обсуждение исходный текст |
Ответ на | Re: Rules/Trigges Trade-offs (Bruce Momjian <pgman@candle.pha.pa.us>) |
Ответы |
Re: Rules/Trigges Trade-offs
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Список | pgsql-sql |
Bruce, > > 1) Rules can't use indexes to do their processing, so Rules which query large > > secondary tables can be a bad idea (maybe this has changed?) > > I don't think this is true. Rewrite is before optimizer so it should be > optimized just the same. I was speaking if the Rule has to do a lookup on a 2nd table in the course of its processing; it used to be that such a lookup could not use indexes because Rules are pre-optimizer. This could have changed since 7.1, though. > > 3) There are no AFTER Rules, making, for example, a rule with a table check on > > the new data impractical, so you'd want to use Triggers or Constraints > > We have changed ordering in 7.3 where I think INSERT rules are _after_ > the insert. How would that work? What if I want to reject the insert? -- -Josh BerkusAglio Database SolutionsSan Francisco
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