Re: [PATCHES] pg_freespacemap question

Christopher Kings-Lynne wrote:
>> The point here is that if tuples require 50 bytes, and there are 20
>> bytes free on a page, pgstattuple counts 20 free bytes while FSM
>> ignores the page.  Recording that space in the FSM will not improve
>> matters, it'll just risk pushing out FSM records for pages that do
>> have useful amounts of free space.
> 
> 
> 
> Maybe an overloaded pgstattuple function that allows you to request FSM 
> behavior?
> 

That's a nice idea - could also do equivalently by adding an extra 
column "usable_free_space" or some such, and calculating this using FSM 
logic.

Cheers

Mark