How to remove all hidden parameters from Oracle Database

How do I remove all hidden parameters from Oracle Database before upgrading? I'm using the SQL query below. So what do you recommended?

SELECT name,description from SYS.V$PARAMETER WHERE name LIKE '\_%' ESCAPE '\'

Here are parameters:

_fast_full_scan_enabled
_gby_hash_aggregation_enabled
_like_with_bind_as_equality
_optimizer_push_pred_cost_based
_sort_elimination_cost_ratio
_sqlexec_progression_cost
_trace_files_public
_b_tree_bitmap_plans

Regards,

You'd need to add IS_SPECIFIED (or ISSPECIFIED) to the where clause, as some hidden parameters may be set by... other things.

A parameter can be removed from an spfile by issuing:

ALTER SYSTEM RESET "_some_hidden_parameter" scope = spfile;

You will likely have to stop and start the instance(s) to have the changes take effect.

StackExchange Database Administrators Q#41936, answer score: 7