On 2013-05-23 19:51:48 +0200, Andres Freund wrote:
> I think that the existence of hint bits and the crash safe visibility
> maps should provide sufficient tooling to make freezing unneccessary
> without loosing much information for debugging if we modify the way
> vacuum works a bit.
> That way we know that any page that is all-visible doesn't ever need to
> look at xmin/xmax since we are sure to have set all relevant hint
> bits.
One case that would make this problematic is row level locks on
tuples. We would need to unset all visible for them, otherwise we might
do the wrong thing when looking at xmax...
Greetings,
Andres Freund
-- Andres Freund http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services
