Toast space grows

Hello,

i have problem with following table...

create table dataaction (
id INT4 not null,
log text,
primary key (id)
);

It is the table for storing results of long running jobs. The log attribute
takes approximately 5MB for one row (there is about 300 rows). My problem
is, that table dataaction takes after restoring about 1,5G, but in few days
grows to 79G(Toast space)... Vacuum on the table doesn't finish.

Where can be the problem?? How to solve it, how to shrink toast space??

Any help will be appretiated.

Kind regards,

Pavel Rotek