Re: Skipping logical replication transactions on subscriber side

On Wed, Mar 16, 2022 at 7:58 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Wed, Mar 16, 2022 at 6:03 AM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> >
> > On Tue, Mar 15, 2022 at 7:18 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > >
> > > On Tue, Mar 15, 2022 at 11:43 AM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> > > >
> > >
> > > 6.
> > > @@ -1583,7 +1649,8 @@ apply_handle_insert(StringInfo s)
> > > TupleTableSlot *remoteslot;
> > > MemoryContext oldctx;
> > >
> > > - if (handle_streamed_transaction(LOGICAL_REP_MSG_INSERT, s))
> > > + if (is_skipping_changes() ||
> > >
> > > Is there a reason to keep the skip_changes check here and in other DML
> > > operations instead of at one central place in apply_dispatch?
> >
> > Since we already have the check of applying the change on the spot at
> > the beginning of the handlers I feel it's better to add
> > is_skipping_changes() to the check than add a new if statement to
> > apply_dispatch, but do you prefer to check it in one central place in
> > apply_dispatch?
> >
>
> I think either way is fine. I just wanted to know the reason, your
> current change looks okay to me.
>

I feel it is better to at least add a comment suggesting that we skip
only data modification changes because the other part of message
handle_stream_* is there in other message handlers as well. It will
make it easier to add a similar check in future message handlers.

--
With Regards,
Amit Kapila.