Audit_Trail parameter's value is set to OS

Hi gurus,

in our environment, audit related parameter are set to:

audit_sys_operations	boolean	TRUE
audit_syslog_level	string	LOCAL6.DEBUG
audit_trail	string	OS

rsyslog daemon is running and the audit file is written to "/var/log/local6.log" file.

I have executed the below command on my database for auditing some specific tasks.

audit insert, update, delete on scott.test_adg by session;

And do the insert, update, delete accordingly for testing the effect. The "local6.log" file is written the log file like following format. It does not showing me the statement i have executed.

:: insert ::