Re: Improving count(*)
От | Steve Wampler |
---|---|
Тема | Re: Improving count(*) |
Дата | |
Msg-id | 437DCF4A.9030802@noao.edu обсуждение исходный текст |
Ответ на | Re: Improving count(*) (Tom Lane <tgl@sss.pgh.pa.us>) |
Список | pgsql-hackers |
Tom Lane wrote: > Simon Riggs <simon@2ndquadrant.com> writes: > >>From here, another proposal. We have a GUC called count_uses_estimate >>that is set to off by default. If set to true, then a count(*) will use >>the planner logic to estimate number of rows in the table and return >>that as the answer, rather than actually count the row. > > > Ugh. Why not just provide a function to retrieve the planner estimate, > but *not* call it count(*)? It would fit nicely with the contrib/dbsize > stuff (or I should say, the stuff formerly in dbsize...) That would completely remove my needs for a fast count() - all I want is a way to quickly estimate table sizes for an operator's display. Tom's suggestion would provide exactly that. -- Steve Wampler -- swampler@noao.edu The gods that smiled on your birth are now laughing out loud.
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