Re: query speed depends on lifetime of frozen db?
От | Martijn van Oosterhout |
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Тема | Re: query speed depends on lifetime of frozen db? |
Дата | |
Msg-id | 20020928020558.GA28628@svana.org обсуждение исходный текст |
Ответ на | Re: query speed depends on lifetime of frozen db? (Andriy Tkachuk <ant@imt.com.ua>) |
Список | pgsql-general |
On Fri, Sep 27, 2002 at 05:58:05PM +0300, Andriy Tkachuk wrote: > On Fri, 27 Sep 2002, Martijn van Oosterhout wrote: > > > On Fri, Sep 27, 2002 at 01:28:13PM +0300, Andriy Tkachuk wrote: > > > On Fri, 27 Sep 2002, Martijn van Oosterhout wrote: > > > > What is the output of EXPLAIN ANALYSE <query>; > > > > > > There is EXPLAIN ANALYSE when query is heavy: > > > > Oookaaay. Your query is *evil*. 14 subqueries executed for *each* row of > > output!?! I reackon you could improve your query just by rewriting it into a > > better form. How can you have 10 subqueries to the same table? > > YES! You right! > Just after restirong db i made vacuumdb -z -f > and query become heavy! > > Does one have any ideas how to ovecome this!? Firstly, how is calc_account() defined? Is it doing subqueries? If it is then the planner won't be seeing them. Is it optimised? calc_account (u.uid, 1030827600) as start_account, calc_account (u.uid, 1032178388) as end_account, -- Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ > There are 10 kinds of people in the world, those that can do binary > arithmetic and those that can't.
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