just VACUUM, marks expired data in tables and
indexes for future reuse; it does not attempt
to reclaim the space used by this expired data unless the space is
- at the end of the table and an exclusive lock can be obtained easily
- on the table. Unused space at the start or middle of the file does
+ at the end of the table and an exclusive table lock can be easily
+ obtained. Unused space at the start or middle of the file does
not result in the file being shortened and space returned to the
operating system. This variant of VACUUM can be
run concurrently with normal database operations.