(No)Persistence
The [NO]PERSISTENCE option specifies whether an index is recreated when its related base table is modified. This option is valid only for indexes.
There are two options:
WITH PERSISTENCE
Recreates the index when its base table is modified.
WITH NOPERSISTENCE
Drops the index when its base table is modified.
Default: A MODIFY to a storage structure sets an index to NOPERSISTENCE.
Other MODIFY actions (including MODIFY TO RECONSTRUCT) do not change an index's persistence.