On Tue, Aug 18, 2026 at 10:47:44PM +0200, Daniel Gustafsson wrote: >> On 18 Aug 2026, at 19:44, Álvaro Herrera <[email protected]> wrote: >> >> 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. > > Online checksums also use bgworkers but it too should not be running here, and > looking at it I didn't see evidence of it interfering. I'll have another look > in the morning with fresh eyes.
I spent some time looking into this last night. AFAICT this is more likely a buildfarm machine configuration problem than a code problem. For tayra, the failures correlated exactly with a bump in meson_jobs to 72. It has been good since it was lowered to 8. I did recently upgrade akepa's buildfarm client and teach it to test more branches, but the failures didn't occur until around a week later, so the correlation is weaker there. I can't find any clues that point me towards a code problem, either. In any case, it's the only machine with this problem at this point, so I lowered its meson_jobs setting and will keep an eye on it. -- nathan
