Re: Skipping logical replication transactions on subscriber side

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.

Some questions/comments
======================
1. IIRC, earlier, we thought of allowing to use of this option (SKIP)
only for superusers (as this can lead to inconsistent data if not used
carefully) but I don't see that check in the latest patch. What is the
reason for the same?

2.
+ /*
+ * Update the subskiplsn of the tuple to InvalidXLogRecPtr.

I think we can change the above part of the comment to "Clear subskiplsn."

3.
+ * Since we already have

Isn't it better to say here: Since we have already ...?

--
With Regards,
Amit Kapila.