The database for Symantec Data Loss Prevention (DLP) does not automatically delete incidents, and continues to grow in size over the life of the deployment.
Once the data retention period has elapsed for your security policy, you can delete the old incidents. This helps free space in the database and improve system performance.
WARNING: Deleting incidents from the Oracle database is permanent, and cannot be reversed.
Deleting incidents will not necessarily reduce the LOB tablespace sizes.
Deleting incidents will not reduce the physical size nor watermark value of the database footprint where SecureFile is in use.
For more information on the topic of Oracle Database and LOB space https://docs.oracle.com/database/121/ADLOB/adlob_intro.htm#ADLOB45114