On 8 August 2014 16:03, Heikki Linnakangas <hlinnakangas@vmware.com> wrote:
> 1. MMTuple contains the block number of the heap page (range) that the tuple
> represents. Vacuum is no longer needed to clean up old tuples; when an index
> tuples is updated, the old tuple is deleted atomically with the insertion of
> a new tuple and updating the revmap, so no garbage is left behind.
What happens if the transaction that does this aborts? Surely that
means the new value is itself garbage? What cleans up that?
-- Simon Riggs http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services