Re: Indexed views?
От | Tiago Wright |
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Тема | Re: Indexed views? |
Дата | |
Msg-id | 7ece122a040907165222ee08a@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: Indexed views? (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: Indexed views?
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Список | pgsql-hackers |
> > where productname is in the product table, and lotname in the lot > > table. I would be interested in creating an index such as > > > CREATE INDEX ix_vw_lot ON vw_lot (lotname, productname); > > What purpose would this serve that indexes on the separate tables > wouldn't serve? > > > The index would be enough to cover 90% of the queries against > > lot the lot and inventory tables. > > This sounds to me like you are suffering from a common misconception. > Postgres cannot answer queries from the contents of indexes alone. Yes, thanks Tom. This is precisely what I was missing. I searched the archives for the reason why this is so, but I found only one message mentioning the MVCC mechanism. Can you point me in the right direction? I would like to understand the issue. IMHO, a change in this area could deliver great performance improvements. -Tiago
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