Re: Enhance pg_createsubscriber to create required standby.

On Wed, Jun 4, 2025 at 2:39 PM Peter Eisentraut <peter@eisentraut.org> wrote:
>
> On 04.06.25 05:56, Shubham Khanna wrote:
> > Currently, pg_createsubscriber is designed to convert an existing
> > physical replica into a logical subscriber. To use it, the user must
> > manually set up a standby node beforehand, ensure that physical
> > replication is active, and only then run pg_createsubscriber to
> > perform the switchover to logical replication.
> > To simplify this workflow, I propose enhancing the pg_createsubscriber
> > utility to handle the creation of the standby node as part of the
> > pg_createsubscriber itself.
>
> Yes, this was contemplated when pg_createsubscriber was first proposed.
> We opted against it, mainly for simplicity initially.
>
> It's not clear to me how this change now would substantially improve the
> user experience.  The number of characters you type is approximately the
> same.  You still need to support the old mode because the backup might
> not come from pg_basebackup.

In the current functionality, the user must first manually create a
standby or use an existing standby to make it a subscriber. I thought
saving this step for users would be quite helpful. It also helps
streamline the process into a single, cohesive workflow.

>
>  And then you'd have the maintenance
> overhead that every new feature in pg_basebackup would potentially have
> to be passed through or somehow be integrated into pg_createsubscriber.
>

I am not so sure about this because we use other utilities like pg_ctl
in this tool, so same argument could be build for it.

--
With Regards,
Amit Kapila.