I have a postgres script that ran on an RDS instance using the psql tool in pgadmin:

BEGIN;

update table set mytimecolumn = 'this';
update table set mytimecolumn = 'that';
update table set mydatecolumn = 'this';
update table set mydatecolumn = 'that';

COMMIT;

I ran out of space in the middle of the script on the instance and ran ROLLBACK;
My space was not reclaimed even though the script definitely rolled back

Was expecting space to be reclaimed nearly immediately. Can someone explain why it was not reclaimed?