How to Shrink automatic storage tablespaces on DB2 V9.5
Now, in the DB2 v9.5 you can shrink a table space, in the DB2 9.1 it was not possible
To reduce the tablespace utilization, you have to perform the command below:
db2 alter tablespace <tablespace_name> reduce
The reduce command removes as much of the unused space as it can from tablespace so that it can be used by other tablespaces,or containers for other DMS tablespaces that are not using automatic storage, or the operating system itself