Re: Parallel heap vacuum

Hi,

On 2025-09-17 13:25:11 +0200, Tomas Vondra wrote:
> I believe the reason why parallelism is disabled in autovacuum is that
> we want autovacuum to be a background process, with minimal disruption
> to user workload. It probably wouldn't be that hard to allow autovacuum
> to do parallel stuff, but it feels similar to adding autovacuum workers.
> That's rarely the solution, without increasing the cost limit.

I continue to find this argument extremely unconvincing. It's very common for
autovacuum to be continuously be busy with the one large table that has a
bunch of indexes. Vacuuming that one table is what prevents the freeze horizon
to move forward / prevents getting out of anti-wraparound territory in time.

Greetings,

Andres Freund