Obsolete Database Parameters

Oracle provides the view V$OBSOLETE_PARAMETER to display all obsolete and underscored parameters. This view contains the name of the parameter and a flag ISSPECIFIED indicating if the parameter has actually been set in the init.ora file. Keep in mind that Oracle has not really retired all of the parameters contained in V$OBSOLETE_PARAMETER, some of them have been underscored. Underscored parameters are ones that Oracle wants to keep around, but does not want you to use them unless absolutely necessary. These underscored parameters are better know as hidden parameters. They are not documented and they all start with an _, like _lgwr_io_slaves in Oracle8i.

 SELECT name, isspecified
 FROM v$obsolete_parameter;