read_only_open_delayed

I have a 19.10 database with a large number of read only files which takes 21 minutes to open in production when a database switchover happens. Unfortunately this does not meet our RTO and we have tested the switchover/open with the read_only_open_delayed parameter in a test environment which is not an exact prod replica but as close to it as possible.

So in the test environment the open time reduces from 8 minutes to 22 seconds.

SQL> select enabled,count(*) from v$datafile group by enabled;

ENABLED COUNT(*)
---------- ----------

READ ONLY 1091
READ WRITE 496 Keen to understand if anyone else is using this since this parameter has been around since 10.1

Cheers