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Re: Aggregate and many LEFT JOIN - Mailing list pgsql-performance

From Michael Lewis
Subject Re: Aggregate and many LEFT JOIN
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Msg-id CAHOFxGpb-MdAMWmmHJs48tV+DAxUi57P2XKoLnsqEaVSDXJcFA@mail.gmail.com
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In response to Re: Aggregate and many LEFT JOIN  (kimaidou <kimaidou@gmail.com>)
Responses Re: Aggregate and many LEFT JOIN  (kimaidou <kimaidou@gmail.com>)
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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.


Not 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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