Re: How is random_page_cost=4 ok?
От | Decibel! |
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Тема | Re: How is random_page_cost=4 ok? |
Дата | |
Msg-id | 754BF190-FE36-490C-83C6-A28C5CAEEF44@decibel.org обсуждение исходный текст |
Ответ на | Re: How is random_page_cost=4 ok? ("Nikolas Everett" <nik9000@gmail.com>) |
Список | pgsql-hackers |
On Oct 10, 2008, at 7:41 PM, Nikolas Everett wrote: > In any case your experience doesn't match mine. On a machine with a > sizable > raid controller setting random_page_cost higher does generate, as > expected, > plans with more bitmap heap scans which are in fact faster. > > We're running postgres backed by a NetApp 3020 via fiber and have > had a lot of success setting random page cost very high (10). > Sequential reads are just that much faster. I'm not sure if thats > because we've configured something wrong or what, but thats a > really useful knob for us. Is your workload OLTP or OLAP? Promoting seqscans in an OLTP environment seems to be a really bad idea to me... -- Decibel!, aka Jim C. Nasby, Database Architect decibel@decibel.org Give your computer some brain candy! www.distributed.net Team #1828
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