>> Isn't the visibility map already required for proper return results as
>> we use it for index-only scans. I think the optimization-only ship has
>> sailed.
>
> At the moment we can remove it without causing corruption. If we were to
> use it for freezing we couldn't anymore. So there's a difference - how
> big it is I am not sure.
Depends on your definition of corruption, really.
But yes, right now, the vismap can lose bits without causing any
corruption, and making all-frozen depend on it would eliminate that.
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com