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

On Thu, Dec 15, 2022 at 11:22 AM Kyotaro Horiguchi
<horikyota(dot)ntt(at)gmail(dot)com> wrote:
>
> At Thu, 15 Dec 2022 10:29:17 +0530, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote in
> > On Thu, Dec 15, 2022 at 10:11 AM Kyotaro Horiguchi
> > <horikyota(dot)ntt(at)gmail(dot)com> wrote:
> > >
> > > At Thu, 15 Dec 2022 09:18:55 +0530, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote in
> > > > On Thu, Dec 15, 2022 at 7:22 AM Kyotaro Horiguchi
> > > > <horikyota(dot)ntt(at)gmail(dot)com> wrote:
> > > > subscriber was busy enough that it doesn't need to add an additional
> > > > delay before applying a particular transaction(s) but adding a delay
> > > > to such a transaction on the publisher will actually make it take much
> > > > longer to reflect than expected. We probably need to name this
> > >
> > > Isn't the name min_apply_delay implying the same behavior? Even though
> > > the delay time will be a bit prolonged.
> > >
> >
> > Sorry, I don't understand what you intend to say in this point. In
> > above, I mean that the currently proposed patch won't have such a
> > problem but if we apply delay on publisher the problem can happen.
>
> Are you saing about the sender-side delay lets the whole transaction
> (if it have not streamed out) stay on the sender side?
>

It will not stay on the sender side forever but rather will be sent
after the min_apply_delay. The point I wanted to raise is that maybe
the delay won't need to be applied where we will end up delaying it.
Because when we apply the delay on apply side, it will take into
account the other load of apply side. I don't know how much it matters
but it appears logical to add the delay on applying side.

--
With Regards,
Amit Kapila.