Horton

Re: huge SubtransSLRU and SubtransBuffer wait_event

Laurenz Albe <laurenz.albe@cybertec.at>

View thread View on postgr.es
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: "James Pang (chaolpan)" <chaolpan@cisco.com>, "pgsql-performance@lists.postgresql.org" <pgsql-performance@lists.postgresql.org>
Date: 2024-02-01T12:41:53Z
Lists: pgsql-performance 
On Thu, 2024-02-01 at 11:50 +0000, James Pang (chaolpan) wrote:
> We have a Postgresqlv14.8 server, client use Postgresql JDBC connections, today,
> our server see a lot of  “SubtransBuffer” and “SubtransSLRU” wait_event.
> Could you help direct me what’s the possible cause and how to resolve this waits ?

Today, the only feasible solution is not to create more than 64 subtransactions
(savepoints or PL/pgSQL EXCEPTION clauses) per transaction.

Don't use extensions or the JDBC driver option to simulate statement level rollback,
that is the road to hell.

Yours,
Laurenz Albe