Re: Enumize logical replication message actions

On Fri, 23 Oct 2020 at 17:02, Kyotaro Horiguchi <horikyota(dot)ntt(at)gmail(dot)com>
wrote:

> At Fri, 23 Oct 2020 19:53:00 +1100, Peter Smith <smithpb2250(at)gmail(dot)com>
> wrote in
> > On Fri, Oct 23, 2020 at 5:20 PM Kyotaro Horiguchi
> > <horikyota(dot)ntt(at)gmail(dot)com> wrote:
> > >
> > > At Thu, 22 Oct 2020 22:31:41 -0300, Alvaro Herrera <
> alvherre(at)alvh(dot)no-ip(dot)org> wrote in
> > > > On 2020-Oct-22, Ashutosh Bapat wrote:
> > > >
> > > > > On Thu, 22 Oct 2020 at 14:46, Kyotaro Horiguchi <
> horikyota(dot)ntt(at)gmail(dot)com>
> > > > > wrote:
> > > >
> > > > > > pg_send_logicalrep_msg_type() looks somewhat too-much. If we
> need
> > > > > > something like that we shouldn't do this refactoring, I think.
> > > > >
> > > > > Enum is an integer, and we want to send byte. The function asserts
> that the
> > > > > enum fits a byte. If there's a way to declare byte long enums I
> would use
> > > > > that. But I didn't find a way to do that.
> >
> > The pq_send_logicalrep_msg_type() function seemed a bit overkill to me.
>
> Ah, yes, it is what I meant. I didn't come up with the word "overkill".
>
> > The comment in the LogicalRepMsgType enum will sufficiently ensure
> > nobody is going to accidentally add any bad replication message codes.
> > And it's not like these are going to be changed often.
>
> Agreed.
>
> > Why not simply downcast your enums when calling pq_sendbyte?
> > There are only a few of them.
> >
> > e.g. pq_sendbyte(out, (uint8)LOGICAL_REP_MSG_STREAM_COMMIT);
>
> If you are worried about compiler warning, that explicit cast is not
> required. Even if the symbol is larger than 0xff, the upper bytes are
> silently truncated off.
>
>
I agree with Peter that the prologue of LogicalRepMsgType is enough.

I also agree with Kyotaro, that explicit cast is unnecessary.

All this together makes the second patch useless. Removed it. Instead used
Kyotaro's idea in previous mail.

PFA updated patch.

--
Best Wishes,
Ashutosh