Re:

On Mon, May 17, 2021 at 7:13 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> "David G. Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> writes:
> > On Monday, May 17, 2021, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >> It looks like it won't be started if you set
> >> max_logical_replication_workers = 0.
>
> > I was wondering about that. Would you mind posting a link to the code
> > where that is checked? I actually looked though admittedly not that
> hard.
>
> See ApplyLauncherRegister() in src/backend/replication/logical/launcher.c.
> That's called from PostmasterMain(). It doesn't actually *launch* the
> process, but it creates the background worker record that causes it to
> be started a little later.
>
>
Thanks (to you to Dilip).

Given this, should the configuration description for this include the "This
parameter can only be set in postgresql.conf file or on the server command
line." comment, as well as the fact that 0 disables the logical replication
subscribing feature altogether, and precludes the background worker
scheduler process from launching at startup?

https://www.postgresql.org/docs/current/runtime-config-replication.html

max_logical_replication_workers (int)

David J.