Hi,
On 2025-03-06 14:47:08 -0500, Tom Lane wrote:
> Nathan Bossart <nathandbossart@gmail.com> writes:
> > On Thu, Mar 06, 2025 at 01:47:34PM -0500, Tom Lane wrote:
> >> ... I wonder if we could just rip out pg_upgrade's support
> >> for DB-level parallelism, which is not terribly pretty anyway, and
> >> simply pass the -j switch straight to pg_dump and pg_restore.
>
> > That would certainly help for clusters with one big database with many LOs
> > or something, but I worry it would hurt the many database case quite a bit.
>
> I'm very skeptical of that. How many DBs do you know with just one table?
> I think most have enough that they could keep a reasonable number of
> CPUs busy with pg_dump's internal parallelism.
pg_dump as used by pg_upgrade doesn't need to dump table data. Afaict we only
do parallelism in pg_dump for table data and large objects. Outside of the
many-LOs case, there's nothing pg_dump's internal parallelism can accelerate?
So the number of tables in a database is irrelevant, no?
Greetings,
Andres Freund
