Re: Recent "could not register background process" buildfarm failures

On 2026-Aug-18, Tom Lane wrote:

> # +ERROR: could not register background process
> # +HINT: You may need to increase "max_worker_processes".
>
> test_shm_mq itself hasn't changed meaningfully in ages,
> so it seems like some recent change somewhere else has increased
> the probability of not being able to get a worker process.
> Maybe autovacuum is eating too many workers? Any thoughts?

Hm, autovacuum does not use workers from the bgworker pool AFAIK.
Repack concurrently does. However, I don't think we use repack
concurrently anywhere in the standard tests; we only run it in the
test_decoding and injection_point tests, which have separate instances.

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