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

On Tue, Dec 27, 2022 at 11:42 AM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Tue, Dec 27, 2022 at 9:33 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
>
> >
> > BTW, the blocking problem with this patch is to deal with shutdown as
> > discussed in the thread [1].
>
> I will have a look.
>

Thanks!

>  In short, the problem is that at
> > shutdown, we wait for walsender to send all pending data and ensure
> > all data is flushed in the remote node. But, if the other node is
> > waiting due to a time-delayed apply then shutdown won't be successful.
> > It would be really great if you can let us know your thoughts in the
> > thread [1] as that can help to move this work forward.
>
> Okay, so you mean to say that with logical the shutdown will be
> delayed until all the changes are applied on the subscriber but the
> same is not true for physical standby?

Right.

> Is it because on physical
> standby we flush the WAL before applying?
>

Yes, the walreceiver first flushes the WAL before applying.

-- 
With Regards,
Amit Kapila.