Re: Slow count(*) again...
От | bricklen |
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Тема | Re: Slow count(*) again... |
Дата | |
Msg-id | AANLkTimXSWapozrZNdiRXDSm2hdsha1As94NwuS967As@mail.gmail.com обсуждение исходный текст |
Ответ на | Slow count(*) again... (Neil Whelchel <neil.whelchel@gmail.com>) |
Ответы |
Re: Slow count(*) again...
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Список | pgsql-performance |
On Sat, Oct 9, 2010 at 4:26 PM, Neil Whelchel <neil.whelchel@gmail.com> wrote: > Maybe an > estimate(*) that works like count but gives an answer from the index without > checking visibility? I am sure that this would be good enough to make a page > list, it is really no big deal if it errors on the positive side, maybe the > list of pages has an extra page off the end. I can live with that. What I > can't live with is taking 13 seconds to get a page of results from 850,000 > rows in a table. > -Neil- > FWIW, Michael Fuhr wrote a small function to parse the EXPLAIN plan a few years ago and it works pretty well assuming your stats are up to date. http://markmail.org/message/gknqthlwry2eoqey
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