Re: Support logical replication of DDLs

On Fri, Feb 10, 2023 at 10:01 PM vignesh C <vignesh21(at)gmail(dot)com> wrote:
>
> On Fri, 10 Feb 2023 at 21:50, vignesh C <vignesh21(at)gmail(dot)com> wrote:
> > The attached v68 version patch has the changes for the same.
>
> I was not sure if we should support ddl replication of
> create/alter/drop subscription commands as there might be some data
> inconsistency issues in the following cases:
> #node1 who is running in port 5432
> create publication pub_node1 for all tables with ( PUBLISH = 'insert,
> update, delete, truncate');
>
> #node2 who is running in port 5433
> create publication pub_node2 for all tables with(PUBLISH = 'insert,
> update, delete, truncate', ddl = 'all');
> create subscription sub_node2 connection 'dbname=postgres host=node1
> port=5432' publication pub_node1;
>
> #node3
> create subscription sub_node3 connection 'dbname=postgres host=node2
> port=5433 publication pub_node2;
>
> #node1
> create table t1(c1 int );
>
> #node2
> create table t1(c1 int);
> alter subscription sub_node2 refresh publication;
>
> # Additionally this command will be replicated to node3, creating a
> subscription sub2_node2 in node3 which will subscribe data from node1
> create subscription sub2_node2 connection 'dbname=postgres host=node1
> port=5432' publication pub_node1;
>
> After this any insert into t1 from node1 will be replicated to node2
> and node3, additionally node2's replicated data(which was replicated
> from node1) will also be sent to node3 causing inconsistency. If the
> table has unique or primary key constraints, it will lead to an error.
>

Can't one use origin = none here to avoid errors?

--
With Regards,
Amit Kapila.