The ALTER TABLE TO CURRENT statement enables you to refresh the content of a join index without having to drop and recreate the index.
The efficiency of the ALTER TABLE TO CURRENT alternative compared to dropping and recreating a join index depends on how often an ALTER TABLE TO CURRENT request is run and the type of current date condition defined in the join index.
If the join index is refreshed infrequently and the current date condition requires a large volume of old rows to be removed and a large volume of new rows to be inserted, dropping and recreating the join index may be more efficient.