Message-ID: <5cd3d1e119e82e0cd79e0a55c4a9602fa3034392.camel@cybertec.at>
Subject: Re: unstable query plan on pg 16,17,18
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Attila Soki <atiware@gmx.net>
Cc: pgsql-performance@postgresql.org
Date: Mon, 23 Feb 2026 22:44:00 +0100
In-Reply-To: <68CC1E87-6935-4CE9-8D69-5335860C70E8@gmx.net>
References: <ECA94B5A-E5B4-45F7-B1B4-9BF754083164@gmx.net>
	 <e94e4d006975792d72e667bbd0499f9ddec4ed58.camel@cybertec.at>
	 <1695A676-062B-47C5-B302-91E2357DC874@gmx.net>
	 <b2e372392b8a022da81b95b7c823a5729d7fd70f.camel@cybertec.at>
	 <A92040E8-9AFC-4B41-AB19-88E09ACB71AF@gmx.net>
	 <a7e4e5b855ef94b2dd16a59adc794b670e682e27.camel@cybertec.at>
	 <68CC1E87-6935-4CE9-8D69-5335860C70E8@gmx.net>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.58.3 (3.58.3-1.fc43) 
MIME-Version: 1.0
Archived-At: 
 <https://www.postgresql.org/message-id/5cd3d1e119e82e0cd79e0a55c4a9602fa3034392.camel%40cybertec.at>
Precedence: bulk

On Mon, 2026-02-23 at 22:19 +0100, Attila Soki wrote:
> To "switch" between the ok and wrong plans I execute
> vacuumdb -Upostgres -vZ -t schema1.table_k db1
> multiple times (1x-3x) until the plan flips. So I thought the table shoul=
d already have been analyzed.
> In my first email I called table_k as the "tbl_used_in_query"

Ok, I see.  Then a simple ANALYZE won't do.

Perhaps the column needs more detailed statistics?

  ALTER TABLE schema1.table_k ALTER dp_end_dat SET STATISTICS 1000;
  ANALYZE schema1.table_k (dp_end_dat);

> or have I misunderstood that with the analyze?

No; I missed that point.

Yours,
Laurenz Albe