Ioannis Theoharis <theohari@ics.forth.gr> writes:
> Can you explain me in more details what kind of optimization is missing in
> that case?
Uh, no I can't really. It was mentioned on the mailing list with regards to
UNION ALL specifically. I think it applied to inherited tables as well but I
wouldn't know for sure. You could search the mailing list archives for recent
discussions of partitioned tables.
In any acse it was a purely technical detail. Some step in the processing of
the data that could be skipped if there weren't any actual changes to the data
being done or something like that. It made a small but noticeable difference
in the runtime but nothing that made the technique infeasible.
--
greg