On Thu, Jul 27, 2017 at 1:46 PM, Alvaro Herrera
<alvherre@2ndquadrant.com> wrote:
> Claudio Freire wrote:
>
>> > The vacuuming the very large table with no index could also take a
>> > long time, and it scans and vacuums blocks one by one. So I imagined
>> > that we can vacuum the FSM once vacuumed a certain amount of blocks.
>> > And that can avoid bloating table during the long-time vacuum.
>>
>> Could do that. I'll see about doing something of the sort and
>> submitting it as a separate patch.
>
> Vacuuming of the FSM is in no way strictly tied to vacuuming the heap
> (it's not really "vacuuming", it's just about updating the upper layers
> to match the data in the leaves). I think we could use the new autovac
> "workitem" infrastructure and tack an item there once in a while for FSM
> vacuuming ...
Well, it *is* tied in the sense that vacuum is the one massively
adding free space.