how set event non-static skip_unusable_indexes loyal pl/sql package speed adult list delete/insert?

i'm perplexing speed adult information bucket tranquil around pl/sql stored procedure. i've programmatically altered indexes list i wish modernise unusable. i wish seer replace obsolete indexes. i emanate statement:

alter event set skip_unusable_indexes = true

but i subsequently error:

ora-01502: index 'my_index_name' assign such index in
obsolete state

so seems have abandoned change session.

can i change event inside pl/sql package? not, alternative?
how else competence i invalidate (set unusable) indexes speed adult load?

a rather associated doubt .