On 25/10/2013 11:06, Albe Laurenz wrote:
> Just because there is an entry in the index does not imply that the
> corresponding table entry is visible for this transaction.
> To ascertain that, the table row itself has to be checked.
Understood.
> PostgreSQL 9.2 introduced "index only scan" which avoids that
> additional step if it is safe to do so.
It doesn't help in this case - the plan for the same query on a copy of
the database on 9.3 is exactly the same.