So adding a new index to a table means rebuilding ALL the indexes on the table. And it's done row-by-row. That's a super-bogus sorting algorithm.
Want to add a COMMENT to a column? Sorry have to rebuild the table and all its indexes.
What to add a new column? Sorry have to rebuild the table and all its indexes.
Any way to parallelize all this rebuilding? Absolutely not!!!! No economy of scale whatsoever. Everything's row-by-row.
There's a reason why folks fork out the big bucks for Oracle Enterprise. No big bucks available? Or want to invest them in your business rather than shipping them off to Oracle? Have a stiff drink and try to relax.