monline

You can query the instance parameters from the V$PARAMETER or V$PARAMETER2 builtin views, however there're a number of hidden parameters (referenced in various troubleshooting tips available on the net) that you cannot check through any of the documented V$* views.

You can list all instance parameters with the following query (executed as the SYS user):

The parameters starting with an underscore are the "hidden" ones. You should think twice before you decide to touch them ... but sometimes there's simply no other way.

Important!
You might loose support for your DB if you modify a hidden parameter that is not approved by Oracle Support itself! It's wise to ask Oracle (or search MetaLink) before you accidentally throw out all the money that your company spent on buying support.