Re: JOIN on partitions is very slow
От
Thomas Kellerer
Тема
Re: JOIN on partitions is very slow
Дата
Msg-id
7cdfd0d6-e4d3-7351-f13c-696460853657@gmx.net
Ответ на
Re: JOIN on partitions is very slow (Michael Lewis)
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Дерево обсуждения
JOIN on partitions is very slow daya airody <daya.airody@gmail.com>
Re: JOIN on partitions is very slow Michael Lewis <mlewis@entrata.com>
Re: JOIN on partitions is very slow daya airody <daya.airody@gmail.com>
Re: JOIN on partitions is very slow Michael Lewis <mlewis@entrata.com>
Re: JOIN on partitions is very slow Thomas Kellerer <shammat@gmx.net>
Re: JOIN on partitions is very slow daya airody <daya.airody@gmail.com>
Michael Lewis schrieb am 23.03.2020 um 17:16: > Yes. I can tweak the query. Version of postgres is 9.5.15. I have > about 20 partitions for company_sale_account table. I do have an > index on company name. > > I need to use DISTINCT as i need to remove the duplicates. > > > DISTINCT is a sign of improper joins most of the time in my > experience. Often, just changing to group by is faster As none of the columns of the joined table are used, most probably this should be re-written as an EXISTS condition. Then neither GROUP BY nor DISTINCT is needed.
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