Re: Potential "AIO / io workers" inter-worker locking issue in PG18?

Hi,

On 2025-10-06 18:09:25 +0200, Marco Boeringa wrote:
> I should have phrased it better. The high processor and core activity is not
> unexpected. The code is designed to saturate the processor and maximize
> throughput by careful design of the Python threading stuff. It is just that
> all the jobs send to PostgreSQL via ODBC for the specific step in the
> processing and with the small Italy extract, should return in less than 10
> seconds (which they do in those lucky runs I do not observe the issue), but
> some of the jobs for the specific step don't, e.g. 30 jobs return within 10
> seconds, then the remaining 14 unexpectedly get stuck for 2 hours before
> returning, all the while staying at the same high core usage they were
> initiated with.

> So some of the PostgreSQL database sessions, as I already explained show up
> in pgAdmin as 'active' with no wait events or blocking pids, simply take an
> excessive amount of time, but will ultimately return.

We need a profile of those processes while they use excessive amount of
time. If they don't have wait events they're using CPU time, and seeing a
profile of where all that time is spent might provide enough information where
to look in more detail.

Greetings,

Andres Freund