Re: Aggregate and many LEFT JOIN
| От | kimaidou |
|---|---|
| Тема | Re: Aggregate and many LEFT JOIN |
| Дата | |
| Msg-id | CAMKXKO5qvnLYCYRJux4yaN=Lj-phCgnE+KBere7VS7d31z78JA@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Aggregate and many LEFT JOIN (Michael Lewis <mlewis@entrata.com>) |
| Ответы |
Re: Aggregate and many LEFT JOIN
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| Список | pgsql-performance |
I manage to avoid the disk sort after performing a VACUUM ANALYSE;
And with a session work_mem = '250MB'
* EXPLAIN https://explain.depesz.com/s/nJ2y
It stills spent 16s
It seems this kind of query will need better hardware to scale...
Thanks for your help
Le lun. 25 févr. 2019 à 19:30, Michael Lewis <mlewis@entrata.com> a écrit :
On Mon, Feb 25, 2019 at 2:44 AM kimaidou <kimaidou@gmail.com> wrote:I have better results with this version. Basically, I run a first query only made for aggregation, and then do a JOIN to get other needed data.* SQL : http://paste.debian.net/1070007/* EXPLAIN: https://explain.depesz.com/s/D0lNot really "fast", but I gained 30%It still seems that disk sort and everything after that is where the query plan dies. It seems odd that it went to disk if work_mem was already 250MB. Can you allocate more as a test? As an alternative, if this is a frequently needed data, can you aggregate this data and keep a summarized copy updated periodically?
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