public inbox for [email protected]
help / color / mirror / Atom feedFrom: Laurenz Albe <[email protected]>
To: Attila Soki <[email protected]>
To: [email protected]
Subject: Re: unstable query plan on pg 16,17,18
Date: Mon, 23 Feb 2026 10:41:57 +0100
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
On Mon, 2026-02-23 at 10:37 +0100, Attila Soki wrote:
> When upgrading from PostgreSQL 14.4, I noticed that one of my somewhat complex
> analytical queries sometimes gets an inefficient plan under PostgreSQL 16, 17, and 18.
> Under 14.4, the query runs with a stable plan and completes in 19 to 22 seconds.
> In newer versions, the plan seems to be unstable, sometimes the query completes
> in 17 to 20 seconds, sometimes it runs for 5 to 18 minutes with the inefficient plan.
> This also happens even if the data is not significantly changed.
This is very likely owing to a bad estimate.
Could you turn on "track_io_timing" and send us the EXPLAIN (ANALYZE, BUFFERS) output
for both the good and the bad plan?
Yours,
Laurenz Albe
view thread (25+ messages) latest in thread
reply
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: [email protected]
Cc: [email protected], [email protected]
Subject: Re: unstable query plan on pg 16,17,18
In-Reply-To: <[email protected]>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox