Logical replication behaves similarly to normal DML operations in that
the data will be updated even if it was changed locally on the subscriber
node. If incoming data violates any constraints the replication will
stop. This is referred to as a conflict. When
operations, missing data will not produce a conflict and such operations
will simply be skipped.
A conflict will produce an error and will stop the replication; it must be resolved manually by the user. Details about the conflict can be found in the subscriber's server log.
The resolution can be done either by changing data on the subscriber so
that it does not conflict with the incoming change or by skipping the
transaction that conflicts with the existing data. The transaction can be
skipped by calling the
pg_replication_origin_advance() function with
node_name corresponding to the subscription name,
and a position. The current position of origins can be seen in the
pg_replication_origin_status system view.