Purging Data

In PPM schema, we capture and store change data in <ppm_table>_cdc tables. We use the DBMS_SCHEDULER package to create a purge job named cdc$_default_purge_job. This purge job calls the PPM_CDC.PURGE_CDC procedure to remove data that has been processed by incremental ETL. By default, cdc$_default_purge_job runs every 24 hours. You can reschedule the purge job using DBMS_SCHEDULER.SET_ATTRIBUTE and setting the repeat_interval attribute.

Running the cdc$_default_purge_job regularly ensures that the tables do not grow without limit. If you have a large volume of data and need to schedule frequent incremental ETL jobs, you can schedule the cdc$_default_purge_job to run more frequently than the default of every 24 hours.

For information about the DBMS_SCHEDULER package, see the Oracle Database PL/SQL Packages and Types Reference.

Note: Do not manually delete data in <ppm_table>_cdc tables. Always call the PURGE_CDC procedure to remove them, otherwise, the data in PPM schema and reporting schema are not synchronized.