Re: Logical Replication of Multiple Schema Versions

On 2019-12-10 08:55, Dan shmidt wrote:
> What is the correct way to perform such an operation?
> Is there a way to keep constraint #1 or the only option is to not allow 
> "breaking" schema changes between versions.

It all depends on the specific schema changes you want to make.  You can 
add columns on the subscriber and remove columns on the publisher 
without breaking things (unless there are not-null constraints). 
Renaming columns will break replication until you rename them 
everywhere.  Column type changes will usually just work as long as the 
data fits into both the old and the new type.

You really need to carefully plan and test each class of scenarios 
separately.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services