Re: Support worker_spi to execute the function dynamically.

On Fri, Jul 21, 2023 at 4:05 PM Masahiro Ikeda <ikedamsh(at)oss(dot)nttdata(dot)com> wrote:
>
> > In SQL tests, I ensured worker_spi doesn't start static bg workers by
> > setting worker_spi.total_workers = 0. Again, all of this is not
> > necessary, but it will be a very good example for someone writing
> > extensions and play around with custom config files, SQL and TAP tests
> > etc.
>
> Thanks for making the patch. I confirmed it works in my environments.

Thanks for verifying.

> I have some questions about the patch.
>
> (1)
>
> Do we need to change the minValue from 1 to 0 to support
> worker_spi.total_workers = 0?
>
> DefineCustomIntVariable("worker_spi.total_workers",
> "Number of workers.",
> NULL,
> &worker_spi_total_workers,
> 2,
> 1,
> 100,
> PGC_POSTMASTER,
> 0,
> NULL,
> NULL,
> NULL);

No, let's keep it that way.

> (2)
>
> Do we need "worker_spi.total_workers = 0" and
> "shared_preload_libraries = worker_spi" in dynamic.conf.
>
> Currently, the static bg workers will not be launched because
> "shared_preload_libraries = worker_spi" is removed. So
> "worker_spi.total_workers = 0" is meaningless.

You're right. worker_spi.total_workers = 0 in custom.conf has no
effect. without shared_preload_libraries = worker_spi. Removed that.

> (3)
>
> We need change and remove them.
>
> > # Copyright (c) 2021-2023, PostgreSQL Global Development Group
> >
> > # Test replication statistics data in pg_stat_replication_slots is sane
> > after
> > # drop replication slot and restart.

Modified.

I'm attaching the v2 patch. Thoughts?

--
Bharath Rupireddy
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com