| From: | Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> |
|---|---|
| To: | Nagaraj Raj <nagaraj(dot)sf(at)yahoo(dot)com> |
| Cc: | Pgsql Performance <pgsql-performance(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Query performance issue |
| Date: | 2020-09-04 21:36:35 |
| Message-ID: | 20200904213635.hvz2pxmmj3tatv26@development |
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| Lists: | pgsql-performance |
On Fri, Sep 04, 2020 at 09:18:41PM +0000, Nagaraj Raj wrote:
> I have a query which will more often run on DB and very slow and it is doing 'seqscan'. I was trying to optimize it by adding indexes in different ways but nothing helps.
>Any suggestions?
>
1) It's rather difficult to read the query plan as it's mangled by your
e-mail client. I recommend to check how to prevent the client from doing
that, or attaching the plan as a file.
2) The whole query takes ~3500ms, and the seqscan only accounts for
~200ms, so it's very clearly not the main issue.
3) Most of the time is spent in sort, so the one thing you can do is
either increasing work_mem, or adding index providing that ordering.
Even better if you include all necessary columns to allow IOS.
regards
--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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