Types of DDL Changes Ignored

When a statement such as CREATE TABLE AS SELECT is executed on the source database, the Capture process extracts the statement as the INSERT row LCRs. The CREATE TABLE AS SELECT statement actually involves an INSERT statement. Therefore, it is natural that the Streams capture process extracts the DML changes.

In addition, the following types of changes are also ignored by a Capture process:

• The session control statements ALTER SESSION and SET ROLE, etc. which are very specific to the application environment in which they are used.
   

• The system control statement: ALTER SYSTEM.
   

• Invocations of PL/SQL procedures.  However, the invocation is not captured if the execution, such as the PL/SQL procedure, makes changes to the tables. Such changes are captured by the Capture process.

Note:  Online table redefinition, using the dbms_redefinition package, is not supported on a table or schema for which a Capture process captures the changes.

Effect of nologging and unrecoverable

nologging or unrecoverable operations are often used by administrators and application users to increase performance levels and to load large data sets into the database tables in a relatively short time. DBAs are willing to take the risk of re-loading such data in case a media recovery is performed and the non-logged operations are not played back during the recovery.