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

On Thu, 28 Jan 2021 at 12:22, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> wrote:
> On Wed, Jan 27, 2021 at 7:35 PM Li Japin <japinli@hotmail.com> wrote:
>> > I don't see any problem if ALTER SUBSCRIPTION ... ADD PUBLICATION with
>> > refresh true refreshes only the newly added publications, because what
>> > we do in AlterSubscription_refresh() is that we fetch the tables
>> > associated with the publications from the publisher, compare them with
>> > the previously fetched tables from that publication and add the new
>> > tables or remove the table that don't exist in that publication
>> > anymore.
>> >
>> > For ALTER SUBSCRIPTION ... DROP PUBLICATION, also we can do the same
>> > thing i.e. refreshes only the dropped publications.
>> >
>> > Thoughts?
>>
>> Agreed. We just only need to refresh the added/dropped publications.  Furthermore, for publications that will be dropped, we do not need the “copy_data” option, right?
>
> I think you are right. The copy_data option doesn't make sense for
> ALTER SUBSCRIPTION ... DROP PUBLICATION, maybe we should throw an
> error if the user specifies it. Of course, we need that option for
> ALTER SUBSCRIPTION ... ADD PUBLICATION.
>

Thanks for your confirm.  Attached v3 patch fix it.

* v3-0001
Only refresh the publications that will be added/dropped, also remove "copy_data"
option from DROP PUBLICATION.

* v3-0002
Add a new testcase for DROP PUBLICATION WITH (copy_data).

* v3-0003
Remove the reference of REFRESH PUBLICATION in DROP PUBLICATION.

* v3-0004
Do not change.

Attaching v3 patches, please consider these for further review.

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