RE: Query Tunning related to function

Hi,

This part of the function is odd and must be dropped:

IF (ret_status = payment_rec)

THEN

ret_status := payment_rec;

I didn’t look really the function code and stopped on the view referenced by the cursor.

The view (we know it just by its name) used in the function is a black box for us. Perhaps it is important to begin optimization there!

If values 'PAID' and 'MANUALLYPAID' are an important percentage of table rows forcing index use is not a good thing especially when it is done with a non-optimized function.

If rows with values 'PAID' and 'MANUALLYPAID' constitute a little percentage of the table, then the partial index plus rewriting the query would be much more efficient

Select

payment_sid_c,

lms_app.translate_payment_status(payment_sid_c) as paymentstatus

from

lms_app.lms_payment_check_request

where

lms_app.translate_payment_status(payment_sid_c) IN ('PAID', 'MANUALLYPAID')

group by

payment_sid_c

If not, you can gain some performance if you rewrite your query to be like this:

Select

payment_sid_c,

lms_app.translate_payment_status(payment_sid_c) as paymentstatus

from

lms_app.lms_payment_check_request

group by

payment_sid_c

having

lms_app.translate_payment_status(payment_sid_c) IN ('PAID', 'MANUALLYPAID')

And you can also try to write the query like this:

Select t.payment_sid_c, lms_app.translate_payment_status(t.payment_sid_c)

From

(

Select

payment_sid_c

from

lms_app.lms_payment_check_request

group by

payment_sid_c

having

lms_app.translate_payment_status(payment_sid_c) IN ('PAID', 'MANUALLYPAID')

) t

Regards

Michel SALAIS

De : Kumar, Mukesh <MKumar(at)peabodyenergy(dot)com>
Envoyé : jeudi 14 avril 2022 16:45
À : Ranier Vilela <ranier(dot)vf(at)gmail(dot)com>
Cc : pgsql-performance(at)postgresql(dot)org; MUKESH KUMAR <mukesh(dot)kumar14(at)tcs(dot)com>
Objet : RE: Query Tunning related to function

Hi Rainer ,

We tried to create the partial ‘index on table but it did not help, and it is taking approx. 7 sec now.

Also we tried to force the query to use the index by enabling the parameter at session level

set enable_seqscan=false;

and it is still taking the time below is the explain plan for the same

https://explain.depesz.com/s/YRWIW#stats

Also we running the query which is actually used in application and above query is used in below query. Below is the explain plan for same.

https://explain.depesz.com/s/wktl#stats

Please assist

Thanks and Regards,

Mukesh Kuma

From: Ranier Vilela <ranier(dot)vf(at)gmail(dot)com <mailto:ranier(dot)vf(at)gmail(dot)com> >
Sent: Thursday, April 14, 2022 7:56 PM
To: Kumar, Mukesh <MKumar(at)peabodyenergy(dot)com <mailto:MKumar(at)peabodyenergy(dot)com> >
Cc: pgsql-performance(at)postgresql(dot)org <mailto:pgsql-performance(at)postgresql(dot)org> ; MUKESH KUMAR <mukesh(dot)kumar14(at)tcs(dot)com <mailto:mukesh(dot)kumar14(at)tcs(dot)com> >
Subject: Re: Query Tunning related to function

Em qui., 14 de abr. de 2022 às 08:01, Kumar, Mukesh <MKumar(at)peabodyenergy(dot)com <mailto:MKumar(at)peabodyenergy(dot)com> > escreveu:

Hi Team,

We are running the below query in PostgreSQL and its taking approx. 8 to 9 sec to run the query.

Query – 1

Select * from

(

Select payment_sid_c,

lms_app.translate_payment_status(payment_sid_c) AS paymentstatus

from

lms_app.lms_payment_check_request

group by payment_sid_c) a

where paymentstatus in ('PAID', 'MANUALLYPAID')

The explain plan and other details are placed at below link for more information. We have checked the indexes on column but in the explain plan it is showing as Seq Scan which we have to find out.

https://explain.depesz.com/s/Jsiw#stats <https://urldefense.com/v3/__https:/explain.depesz.com/s/Jsiw*stats__;Iw!!KupS4sW4BlfImQPd!M8K66GpB-7DvYJA0HYFVpY9mtO6TaqIGRjTLI2G1WNjwK8KA9I8JaEr9OWwGy5F6fC4Ed5dwEjCf_1rBCDg9rA$>

This query is using a function translate_payment_status on column payment_sid_c whose script is attached in this mail

Could please anyone help or suggest how to improve the query performance.

You can try create a partial index that help this filter:

Filter: ((lms_app.translate_payment_status(payment_sid_c))::text = ANY ('{PAID,MANUALLYPAID}'::text[]))

See at:

https://www.postgresql.org/docs/current/indexes-partial.html <https://urldefense.com/v3/__https:/www.postgresql.org/docs/current/indexes-partial.html__;!!KupS4sW4BlfImQPd!M8K66GpB-7DvYJA0HYFVpY9mtO6TaqIGRjTLI2G1WNjwK8KA9I8JaEr9OWwGy5F6fC4Ed5dwEjCf_1quLi3m8Q$>

regards,

Ranier Vilela