Leonardo Francalanci <m_lists@yahoo.it> writes:
> BTW can someone explain to me which are the cases where the
> patch actually helps?
Cases with lots of irrelevant indexes. Zoltan's example had 4 indexes
per child table, only one of which was relevant to the query. In your
test case there are no irrelevant indexes, which is why the runtime
didn't change.
regards, tom lane