DDL on Cached Oracle Database Tables May Cause Failure

DDL operations that are performed on an Oracle database table that is being cached in TimesTen may cause a failure on the cache group. For example, the user drops a column on the Oracle database table that is being cached in TimesTen. When the cache group is propagated or flushed, TimesTen will update the column that no longer exists in the Oracle database table. When the cache group loads or refreshes, then TimesTen attempts to retrieve data from the column that has been dropped.

The following cache group operations may fail:

• Autorefresh does not occur.

• AWT cache group operations are not propagated or refreshed to or from the Oracle database.

• Cache group load or propagate fails.

If you suspect the cache group operations are not working properly because of a DDL operation on the Oracle database base table, then use DDL tracking to diagnose the issue. DDL tracking saves the change history for all the cached Oracle database tables. The SQL statement and when it was executed are each written to a TimesTen table in the cache administrator user schema on the Oracle database.

For more information on how to create the DDL tracking objects and how to enable DDL tracking for the base table within the Oracle database, see Tracking DDL Statements Issued on Cached Oracle Database Tables" in the Oracle TimesTen In-Memory Database Cache Guide. For details on the built-in procedure used for enabling or disabling DDL tracking, see ttCacheDDLTrackingConfig in Oracle TimesTen In-Memory Database Reference.