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

On 23.03.21 16:08, Japin Li wrote:
> I check the duplicates for newpublist in merge_publications(). The code is
> copied from publicationListToArray().
> 
> I do not check for all duplicates because it will make the code more complex.
> For example:
> 
> ALTER SUBSCRIPTION mysub ADD PUBLICATION mypub2, mypub2, mypub2;
> 
> If we record the duplicate publication names in list A, when we find a
> duplication in newpublist, we should check whether the publication is
> in list A or not, to make the error message make sense (do not have
> duplicate publication names in error message).

The code you have in merge_publications() to report all existing 
publications is pretty messy and is not properly internationalized.  I 
think what you are trying to do there is excessive.  Compare this 
similar case:

create table t1 (a int, b int);
alter table t1 add column a int, add column b int;
ERROR:  42701: column "a" of relation "t1" already exists

I think you can make both this and the duplicate checking much simpler 
if you just report the first conflict.

I think this patch is about ready to commit, but please provide a final 
version in good time.

(Also, please combine your patches into a single patch.)