OCI-03826
Barrier DDL statement cannot be executed in a shard with both read/write (RU read_write_replication_unit) and read-only (RU read_only_replication_unit) replication units.
- read_write_replication_unit: The number of the read/write replication unit.
- read_only_replication_unit: The number of the read-only replication unit.
Cause
A Barrier DDL statement can only be executed in a shard that is either exclusively read/write or read-only. The shard is found to contain both read/write and read-only replication units. This can also occur if replication units are currently being moved between read/write and read-only shards or regions.
Action
Either disable Barrier DDL and resubmit the DDL statement again, or wait for the replication unit to stabilize after being moved.