用truncate table *** reuse storage吧
REUSE STORAGE Specify REUSE STORAGE to retain the space from the deleted rows
allocated to the table or cluster. Storage values are not reset to the values when the
table or cluster was created. This space can subsequently be used only by new data in
the table or cluster resulting from insert or update operations. This clause leaves
storage parameters at their current settings.
If you have specified more than one free list for the object you are truncating, then the
REUSE STORAGE clause also removes any mapping of free lists to instances and resets
the high-water mark to the beginning of the first extent.
