Why do I need to use DAC from Oracle BI?
Posted by Dylan Wan on January 8, 2007
Here are what happen behind the scene:
- DAC publish the changes from OLTP
- Informatica extracts the changes from the change log published by DAC as well as from the base table
- Informatica load the data to the stage tables and the target tables in the data warehouse
- DAC manage the performance by dropping indexes, truncating stage tables, rebuilding the indexes, and analyzing the tables during the process
If you do not use DAC, you have to write your own custom change capture process and need to redesign from scratch an ETL method that allow the restart of the ETL process from point of failure at record level. The biggest saving is that DAC can survive during the upgrade , while your custom processes cannot.