Although Real-Time Query is a great feature, it requires the Active Data Guard option to be licensed AND it is very easy to turn it on. That has been a concern for some customers I encountered. Now I realized that we have an undocumented parameter to prevent exactly that. Thanks to Marc, who mentioned the MOS Note 1436313.1 in a recent comment!
I am here connected to a Physical Standby database, running on 126.96.36.199 and don’t want to use Real-Time Query. The startup command would normally trigger the database to open READ ONLY, together with a Data Guard Broker configuration, Real-Time Query would be started. Not any more:
SQL> alter system set "_query_on_physical"=false scope=spfile; System altered. SQL> shutdown immediate ORA-01109: database not open Database dismounted. ORACLE instance shut down. SQL> startup ORACLE instance started. Total System Global Area 521936896 bytes Fixed Size 2214936 bytes Variable Size 314573800 bytes Database Buffers 201326592 bytes Redo Buffers 3821568 bytes Database mounted. ORA-16669: instance cannot be opened because the Active Data Guard option is disabled SQL> host oerr ora 16669 16669, 00000, "instance cannot be opened because the Active Data Guard option is disabled" // *Cause: The attempt to open the instance failed because the Active Data // Guard option was not enabled and Redo Apply was either running // or was about to be started by the Data Guard broker. // *Action: Stop Redo Apply or set the database state to APPLY-OFF and then // open the database.
It is still possible to open the Physical Standby READ ONLY when the MRP background process is stopped:
DGMGRL> edit database physt set state=apply-off; Succeeded. SQL> alter database open; Database altered. SQL> select open_mode from v$database; OPEN_MODE -------------------- READ ONLY
Only drawback is that it is an undocumented parameter, so you should confirm with Oracle Support that it is okay to use it in your case.
Conclusion: There is an easy way to prevent license violation by accident with Real-Time Query. Don’t believe it, ask Oracle Support