Column and table collation
When replicating from Amazon RDS for PostgreSQL database to a PostgreSQL-based target database, column and table collations will be replicated to the target.
Information note
To support collation replication, the DBA must ensure that the collations defined for the source Amazon RDS for PostgreSQL database are the same as those defined for the PostgreSQL-based target database.
Non-nullable volumns and primary/unique index names
Non-nullable columns and Primary/Unique Index names are preserved during homogeneous replication.