Where are blocks of free dbspace?
name dbspace, -- dbspace name
f.chknum, -- chunk number
f.extnum, -- extent number of free space
f.start, -- starting address of free space
f.leng free_pages -- length of free space
from sysdbspaces d, syschunks c, syschfree f
where d.dbsnum = c.dbsnum
order by dbspace, free_pages desc