Message-ID: <34dbb623-e7ef-403f-b7b1-082c856f897e@gmail.com>
Date: Sun, 18 May 2025 18:54:24 +0200
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: inefficient/wrong plan cache mode selection for queries with
 partitioned tables (postgresql 17)
To: Maxim Boguk <maxim.boguk@gmail.com>
Cc: pgsql-performance@lists.postgresql.org
References: 
 <CAK-MWwS_2UwF7XPy-8XpcVqUjEveDjDQRbXxPyzvJM+ooWeh9A@mail.gmail.com>
 <b7da2330-1054-4bb8-939a-cb05d377f70f@gmail.com>
 <CAK-MWwRP+OsZhEi5LGZcsWZikMj5+cCmVmK9oKgssFViF13NCQ@mail.gmail.com>
 <8480be46-6e2a-4b12-9f80-78ba3db79dfb@gmail.com>
 <CAK-MWwSgP2_br2jHtZSWYEH-T9tDx73LxqkNez-0kmck_wk=xQ@mail.gmail.com>
Content-Language: en-AU
From: Andrei Lepikhov <lepihov@gmail.com>
In-Reply-To: 
 <CAK-MWwSgP2_br2jHtZSWYEH-T9tDx73LxqkNez-0kmck_wk=xQ@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Archived-At: 
 <https://www.postgresql.org/message-id/34dbb623-e7ef-403f-b7b1-082c856f897e%40gmail.com>
Precedence: bulk

On 5/12/25 16:04, Maxim Boguk wrote:
> On Mon, May 12, 2025 at 4:48 PM Andrei Lepikhov <lepihov@gmail.com 
>     If I'm not mistaken, it will work with all PG versions that are
>     currently in support. What do you think?
> 
> 
> Such extension would be very useful (and in general - the solution based 
> on the actual execution data - seems more stable/predictable than the 
> plan cost based selection which is currently used by postgresql).
I've written a sketch of such an extension; see [1]. A trivial strategy 
is implemented to force prepared statements to use a generic plan if the 
planning time exceeds the maximum execution time.
It is just an example - it is written in plpgsql, and you can implement 
alternative strategies independently.
I would be happy if it covered your use case. Any feedback is welcome.

[1] https://github.com/danolivo/pg_mentor/tree/main

-- 
regards, Andrei Lepikhov