Oracle replication: ORA-23318: a DDL failure has occurred

How do I correct this ORA-23318 error?

Answer: In your case, you are adding a table column to a replicated table.  Most experienced Oracle DBA's will will manually alter the table and their associated snapshot on the local and remote databases, rather than use the  dbms_repcat.alter_master_repobject procedure.  Oracle recommends using the following procedure for altering replicated tables:

1 - Suspend the required master group of which the table exists:
 
    exec dbms_repcat.suspend_master_activity('scott')
 
 2. add a new column to the table:
 
 exec dbms_repcat.alter_master_repobject(
   'scott',
   'dept',
   'table',
    - ddl_text=>'alter table scott.dept modify(added_column default ''n''
    - constraint dept_ad_nn not null)
 )';
 
 3. regenerate application support for the table:
 
 exec dbms_repcat.generate_replication_support(
   sname => 'scott', -
   oname =>'dept',
   type => 'table',
   min_communication => true);
 
 4. resume multi-master replication:
 
 exec dbms_repcat.resume_master_activity('scott',true);

I also recommend the book "Oracle Replication" for tips and working replication scripts. 

Diagnosing the ORA-23318 error

The Oracle documentation notes that the ORA-23318 is a generic error with many possible causes:

ORA-23318: a DDL failure has occurred

Cause: User-supplied or system-generated DDL did not execute successfully.

Action: Examine DDL, database state, repcatlog, and all_errors to determine why the failure occurred.

Bugs relating to ORA-23318

• Bug 1280292 - Fixed in 8.1.7.1
   
• Bug 1280292 - This bug was introduced in 8.1, which can affect the ALTER TABLE command when it is done via the ALTER_MASTER_REPOBJECT package. This has been resolved in 9i and there are patches for 8i versions.
   
• Bug 1346937 - Relating to using alter_master_repobject.
   
• Bug 1881708 -
   
• Bug 2182554 - When upgrading OID 211 (8.1.7 RDBMS) to OID 902 (902 RDBMS). One of the upgrade tasks is to alter a table column from varchar2(2000) => varchar2(4000).

Oracle notes on the ORA-23318 error

The MOSC note Diagnosing ORA-23318 notes these possible causes for the ORA-23318 error:

• Invalid Trigger replication - The most common cause of the ORA-23381 error is when replicating triggers, causing the ORA-23318 when the remote trigger does not have the same dependent objects (sequences, tables, packages) as the local trigger. MOSC recommends that replicated triggers use dbms_reputil.from_remote to avoid the re-replication of data.
   
• Calling alter_master_repobject with default value - Using the alter_master_repobject package and a column is being added an ORA-23318 will be produced if a default value is included in the DDL for the added column. When the column is added with a default, all existing rows will have to have the value inserted, which is DML. Since the group is quiesced, DML is not allowed. If the column is added and then modified to use the default, no DML is required. . . Note 1064130.6 discusses this issue and offers a valid work around that
  utilizes replication views.
   
• Using unsupported Data Types - Executing dbms_repcat.create_snapshot_repobject can fail with ORA-23318 error when the table has a column of type ORDSYS.Ordimage. It is an unsupported column type for Advanced Replication. See Oracle8i Replication Guide, chapter 'Considerations for Replicated Tables'. Use a BLOB, CLOB or NCLOB as column type.
   
• Refresh job fails - You can get an ORA-23318 when refreshing a snapshot (or materialized view) if the base table was altered (e.g. new column, changed constraint) without rebuilding the snapshot.