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From: Ron Johnson <[email protected]>
To: pgsql-general <[email protected]>
Subject: Re: can stored procedures with computational sql queries improve API performance?
Date: Wed, 10 Jul 2024 16:17:28 -0400
Message-ID: <CANzqJaCazZXsg4UuJhLOf8KC_1+bZLpA35R-MHA2n4Muky9Q0w@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>

On Tue, Jul 9, 2024 at 8:58 PM Krishnakant Mane <[email protected]> wrote:

> Hello.
>
> I have a straight forward question, but I am just trying to analyze the
> specifics.
>
> So I have a set of queries depending on each other in a sequence to
> compute some results for generating financial report.
>
> It involves summing up some amounts from tuns or of rows and also on
> certain conditions it categorizes the amounts into types (aka Debit
> Balance, Credit balance etc).
>
> There are at least 6 queries in this sequence and apart from 4 input
> parameters. these queries never change.
>
> So will I get any performance benefit by having them in a stored
> procedure rather than sending the queries from my Python based API?


One problem is that the query planner reverts to a generic query plan if
you execute the same query over and over in a loop in the SP.

That bit us once.  A big SP that had been running "normally" for months
suddenly went from about 20 minutes to six hours.  The solution (given by
someone on this list a couple of years ago) was to add "set plan_cache_mode
= force_custom_plan;" above the call.

That way, the query plan was updated every time.  Performance dropped to
about 8 minutes IIRC.

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