The magic of oracle database index ------- set the index to be invisible

alter index owner. index name invisible;
makes the index invisible to the optimizer, which is equivalent to non-existence. But still maintained by dml.
Observe for 1-2 months, it is really unnecessary, and then delete it.

If you find that the index is really needed, you can execute
alter index owner. index name visible;
to make it visible.

If you are not sure whether an index will not be used, that is, the risk of changing to invisible is high, you can enable monitoring of the use of the index,
alter index owner. index name monitoring usage;
then, after a period of time, if you find It is useless, and then change to invisible, it is more secure.
But for an index that is very likely to be used, no monitor is needed, because every time it is used, an update will be performed to update the situation of the index being used.