Re: allow changing autovacuum_max_workers without restarting

On Thu, Apr 11, 2024 at 03:37:23PM +0000, Imseih (AWS), Sami wrote:
>> My concern with this approach is that other background workers could use up
>> all the slots and prevent autovacuum workers from starting
>
> That's a good point, the current settings do not guarantee that you
> get a worker for the purpose if none are available,
> i.e. max_parallel_workers_per_gather, you may have 2 workers planned
> and 0 launched.
>
>> unless of
>> course we reserve autovacuum_max_workers slots for _only_ autovacuum
>> workers. I'm not sure if we want to get these parameters tangled up like
>> this, though...
>
> This will be confusing to describe and we will be reserving autovac workers
> implicitly, rather than explicitly with a new GUC.

Yeah, that's probably a good reason to give autovacuum its own worker pool.

--
Nathan Bossart
Amazon Web Services: https://aws.amazon.com