My question: when you vacuum a table and generate 'free_space', who is
allowed to consume this 'free_space'? Is it released to the OS for
general use? Or is it reserved just for the database? If the latter, is
it reserved just for 'wind' (in this case)?
as far as i know this space is mapped as free witinh data-files of table "wind".
thus effectivelyu - your OS doesnt get more free space, nor is (generally speaking) the database.
benefit of this "free space" is that next inserts to wind table will fit inside of this free space - thus stopping bloat of datafiles of this table.
if you would like to reclaim the disk-space, you should consider using vacuum full.
depesz
