Today I got asked by a colleague whether we can do auditing on a Physical Standby that does Real-Time Query. My response was: Probably yes, with AUDIT_TRAIL=OS for the Standby and the audit command specified on the Primary. I did just test that and it really works this way! There is no need to have the AUDIT_TRAIL parameter value different from NONE on the Primary even. Just call a command like

SQL> audit session whenever not successful;

on the Primary and it will reach the Physical Standby via Redo-Apply. I tested that with

SQL> select * from v$version;

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
PL/SQL Release 11.2.0.3.0 - Production
CORE    11.2.0.3.0    Production
TNS for Linux: Version 11.2.0.3.0 - Production
NLSRTL Version 11.2.0.3.0 - Production

but I suppose it will work the same with lower versions. But then: “Don’t believe it, test it!”