=?iso-8859-2?Q?Wojciech_Strza=B3ka?= <wstrzalka(at)gmail(dot)com> writes:
> In my opinion the fact that dropping column doesn't release it's toastable resources is a bug.
To make that happen would require (at least) a full table scan. I think
most people are more interested in DROP COLUMN being a cheap operation
than in having the space be reclaimed quickly.
For a comparison point: large field values that don't happen to get
toasted don't vanish immediately, either.
regards, tom lane