db2pd -db <dbname> -tablespaces

select t.data_object_p_size
     + t.index_object_p_size
     + t.long_object_p_size 
     + t.lob_object_p_size  
     + t.xml_object_p_size
--     + t.col_object_p_size   DB2 v10.5 only
        as psize
      ,c.ROWS_SAMPLED
      ,c.PAGES_SAVED_PERCENT
      ,c.BYTES_SAVED_PERCENT
      ,t.tabschema
      ,t.tabname
      ,t.data_object_p_size
      ,t.index_object_p_size
      ,t.long_object_p_size
      ,t.lob_object_p_size
      ,t.xml_object_p_size
--      ,t.col_object_p_size   DB2 v10.5 only
      ,t.*
 from sysibmadm.admintabinfo t
      left join 
      sysibmadm.ADMINTABCOMPRESSINFO c
      on (t.tabschema, t.tabname) = (c.tabschema, c.tabname) 
 WHERE t.TABSCHEMA NOT LIKE 'SYS%'
 ORDER BY 1 DESC;

ALTER TABLESPACE <tbspacename> LOWER HIGH WATER MARK;

select * from table(mon_get_extent_movement_status(null,null))

ALTER TABLESPACE <tbspacename> REDUCE MAX;