Re: [PATCH 10/16] Introduce the concept that wal has a 'origin' node

Andres Freund <andres@2ndquadrant.com> writes:
> On Tuesday, June 19, 2012 04:17:01 PM Tom Lane wrote:
>> ...  (If you are thinking
>> of something sufficiently high-level that merging could possibly work,
>> then it's not WAL, and we shouldn't be trying to make the WAL
>> representation cater for it.)

> The idea is that if youre replaying changes on node A originating from node B
> you set the origin to *B* in the wal records that are generated during that. 
> So when B, in a bidirectional setup, replays the changes that A has made it 
> can simply ignore all changes which originated on itself.

This is most certainly not possible at the level of WAL.  As I said
above, we shouldn't be trying to shoehorn high level logical-replication
commands into WAL streams.  No good can come of confusing those concepts.
        regards, tom lane