RE: Time delayed LR (WAS Re: logical replication restrictions)

On Thursday, January 19, 2023 10:42 AM Peter Smith <smithpb2250@gmail.com> wrote:
> On Wed, Jan 18, 2023 at 6:06 PM Peter Smith <smithpb2250@gmail.com>
> wrote:
> >
> >  Here are my review comments for the latest patch v16-0001. (excluding
> > the test code)
> >
> ...
> >
> > 8. AlterSubscription (general)
> >
> > I observed during testing there are 3 different errors….
> >
> > At subscription CREATE time you can get this error:
> > ERROR:  min_apply_delay > 0 and streaming = parallel are mutually
> > exclusive options
> >
> > If you try to ALTER the min_apply_delay when already streaming =
> > parallel you can get this error:
> > ERROR:  cannot enable min_apply_delay for subscription in streaming =
> > parallel mode
> >
> > If you try to ALTER the streaming to be parallel if there is already a
> > min_apply_delay > 0 then you can get this error:
> > ERROR:  cannot enable streaming = parallel mode for subscription with
> > min_apply_delay
> >
> > ~
> >
> > IMO there is no need to have 3 different error message texts.  I think
> > all these cases are explained by just the first text (ERROR:
> > min_apply_delay > 0 and streaming = parallel are mutually exclusive
> > options)
> >
> >
>
> After checking the regression test output I can see the merit of your separate
> error messages like this, even if they are maybe not strictly necessary. So feel
> free to ignore my previous review comment.
Thank you for your notification.

I wrote another reason why we wrote those messages in [1].
So, please have a look at it.

[1] -
https://www.postgresql.org/message-id/TYCPR01MB8373447440202B248BB63805EDC49%40TYCPR01MB8373.jpnprd01.prod.outlook.com


Best Regards,
    Takamichi Osumi