Re: Query is slow when order by and limit clause are used in the query - Mailing list pgsql-bugs

From sreekanth vajrapu
Subject Re: Query is slow when order by and limit clause are used in the query
Date
Msg-id CAKPbTYhbZQYxuhUqTMPCaeQ8B0SJ8pwd2yV7vEFkbLC+tG+LKg@mail.gmail.com
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In response to Re: Query is slow when order by and limit clause are used in the query  (Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>)
Responses Re: Query is slow when order by and limit clause are used in the query  (Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>)
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Hi Bharath,

Thanks for the quick reply, I have attached the execution plan for below 3 scenarios. Our application is using 1st Scenario

1) WITH ORDER BY AND LIMIT 30 -- Very slow(3 to 5 seconds)
2) WITH ORDER BY WITHOUT LIMIT -- Very fast(160 MS)
3) WITH ORDER BY WITHOUT LIMIT 100 -- Very fast(160 MS)

Kidney let me know if you need any more details on this.

Thanks,
Sreekanth.



On Mon, May 24, 2021 at 4:33 PM Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> wrote:
On Mon, May 24, 2021 at 4:19 PM sreekanth vajrapu
<sreekanthvajrapu@gmail.com> wrote:
>
>
> Hi Team,
>
> We are having a slow query issue for one of our applications. We are seeing slowness(5 seconds) when we use both ORDER BY and LIMIT 30 clause whereas the same query is performing very good(200 MS) when using only ORDER BY clause.  Also note that the query performed very fast(200 MS) when we increased LIMIT to 100 along with ORDER  BY.
>
>
> Can you please help us if there are any bugs related to this?  OR Can someone kindly provide some solution to this issue?

I think it's good to provide explain (analyze, buffers, costs,
verbose, summary) of the query and a reproducible test case (if
possible). It will be easier for those who investigate the issue.

With Regards,
Bharath Rupireddy.
EnterpriseDB: http://www.enterprisedb.com


--
Thanks & Regards,
Sreekanth
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