The mirror_on_ddl_operation parameter determines what action
CDC Replication takes when it
detects a DDL operation at a source table.
Version—CDC Replication Engine for Oracle XStream version 11.4 or
later
- Applies to
- Source datastores
- Values
- Set this parameter to one of the following values.
-
- STOP
- The default value of the parameter. When CDC Replication detects a DDL change,
replication stops. This action enables you to plan for DDL change in the target datastore. After
altering the target table, update the table definition and choose to either refresh or continue
mirroring.
- IGNORE
- CDC Replication issues an
event that indicates that the DDL change was detected. Replication continues after the DDL change.
Oracle XStream provides data in an LCR ColumnValue for each individual column. CDC Replication column name metadata
that was stored in CDC Replication prior to the DDL
change is matched against the LCR metadata that is described in the ColumnValue of the LCR. For any
matching column names, replication continues based on the data that is found in LCR based on the
CDC Replication table
mapping. Internal CDC Replication metadata is not
updated at the time of the DDL change. Any new columns that are added to LCR are not propagated to
the target. CDC Replication
also does not issue an error for any columns that are known to CDC Replication but not part of the
LCR. Altering a column in a replicated Oracle table might result in various errors in CDC Replication when a DDL change is
ignored. This option can provide temporary resilience to certain table DDL changes, however if you
choose to use it, follow up by a planned updated of CDC Replication metadata and remap the
columns at the earliest opportunity. This step ensures that changes to the table are known to the
distributed CDC Replication
components.
- Default Setting
- STOP