| From: | Attila Soki <atiware(at)gmx(dot)net> |
|---|---|
| To: | Andrei Lepikhov <lepihov(at)gmail(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org, Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> |
| Subject: | Re: unstable query plan on pg 16,17,18 |
| Date: | 2026-02-24 11:37:17 |
| Message-ID: | FF816253-DD7D-4AC2-8CD1-8A5ACB1D1113@gmx.net |
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| Lists: | pgsql-performance |
On 24 Feb 2026, at 12:09, Andrei Lepikhov <lepihov(at)gmail(dot)com> wro
> This update gives us more useful details. In PG14, the join search problem involved at most 9 relations. In PG19, the maximum is now 18 joins. Do you know what your join_collapse_limit is set to? It looks like subplan pull-ups have made things more complex.
> First, we should look into any possible 'rescan cost' issues on our side as developers.
> On your end, please check the join_collapse_limit setting. If needed, try increasing it to around 20. This might help.
join_collapse_limit is not set, so it is the default, 8
I will try if something around 20 helps.
thanks
btw: I working on providing more details to the query
regards,
Attila
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