Re: Free space mapping (was Re: Multi-Versions and Vacuum)

Tom Lane wrote:

>It doesn't need a lot of examination in my mind: the cause is surely
>growth of the index on the toast table.
>
>
You are indeed correct !

A quick check of my test case shows that the toast table growth tails
off ( provided max_fsm_pages is suitably set), and the unbounded growth
comes entirely from the toast index.

Applying REINDEX brings the space usage down to a level that compares
with a non-toasted example.

With respect to the REINDEX workaround -  having to re-start your server
single process for it is a bit fatal if you are  24/7 shop - I think
altering those high hit tables to have attributes detoasted might be
better (row length permitting).

Anyway that has *toasted* the need for my currrent little investigation
(quite enjoyed my romp through the code, so I am not too worried).  I
still have some free time (I am off work after knee operation) so I'm
now looking for another project....

regards

Mark