Re: Support ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION ... syntax

Hi, Bharath

Thanks for your reviewing.

On Tue, 26 Jan 2021 at 12:55, Bharath Rupireddy <bharath(dot)rupireddyforpostgres(at)gmail(dot)com> wrote:
> On Tue, Jan 26, 2021 at 9:25 AM japin <japinli(at)hotmail(dot)com> wrote:
>> > I think it's more convenient. Any thoughts?
>>
>> Sorry, I forgot to attach the patch.
>
> As I mentioned earlier in [1], +1 from my end to have the new syntax
> for adding/dropping publications from subscriptions i.e. ALTER
> SUBSCRIPTION ... ADD/DROP PUBLICATION. But I'm really not sure why
> that syntax was not added earlier. Are we missing something here?
>

Yeah, we should figure out why we do not support this syntax earlier. It seems
ALTER SUBSCRIPTION is introduced in 665d1fad99e, however the commit do not
contains any discussion URL.

> I would like to hear opinions from other hackers.
>
> [1] - https://www.postgresql.org/message-id/CALj2ACVGDNZDQk3wfv%3D3zYTg%3DqKUaEa5s1f%2B9_PYxN0QyAUdCw%40mail.gmail.com
>
> Some quick comments on the patch, although I have not taken a deeper look at it:
>
> 1. IMO, it will be good if the patch is divided into say coding, test
> cases and documentation

Agreed. I will refactor it in next patch.

> 2. Looks like AlterSubscription() is already having ~200 LOC, why
> can't we have separate functions for each ALTER_SUBSCRIPTION_XXXX case
> or at least for the new code that's getting added for this patch?

I'm not sure it is necessary to provide a separate functions for each
ALTER_SUBSCRIPTION_XXX, so I just followed current style.

> 3. The new code added for ALTER_SUBSCRIPTION_ADD_PUBLICATION and
> ALTER_SUBSCRIPTION_DROP_PUBLICATION looks almost same maybe with
> little difference, so why can't we have single function
> (alter_subscription_add_or_drop_publication or
> hanlde_add_or_drop_publication or some better name?) and pass in a
> flag to differentiate the code that differs for both commands.

Agreed.

--
Regrads,
Japin Li.
ChengDu WenWu Information Technology Co.,Ltd.