We initially restricted DDL changes from SYS and SYSTEM because the Oracle database uses these accounts to generate internal DDL changes. At the time, the DDL parser was still relatively new and not fully battle-tested, so we wanted to minimize the number of possible combinations that could cause failures.

I propose we remove the check for handling schema changes and replace it with a new, perhaps internal option called log.mining.schema_changes.username.exclude.list. This new option would default to "SYS,SYSTEM" to preserve the existing behavior but allow users to relax this restriction if they want to capture DDL for such users.