user_name is null in Audit_event table

Hello,

Environment: SAP BI4.0 SP2 (Linux)

Auditing type: Complete

In our environment we have noticed a very large number of events with user_name as null. These events are growing daily and consuming all the DB space.

I have checked service_type_name (from ads_service_type_str table) for those client_type_id (from ADS_EVENT table) and found the below details

Web Intelligence Processing Service

Job Server

Logon without Client ID

Central Management Service

Central Configuration Manager

CMC

BI launch pad

Open Document

Live Office

I couldn't find anything related to this (user_name as null) over net or forums. Please let me know If someone has any idea on the probably reason.

Thanks