On Fri, Mar 3, 2017 at 2:54 PM, Andres Freund <and...@anarazel.de> wrote: > On 2017-02-28 19:12:03 +0530, Pavan Deolasee wrote: >> Since VM bits are only set during VACUUM which conflicts with CIC on the >> relation lock, I don't see any risk of incorrectly skipping pages that the >> second scan should have scanned. > > I think that's true currently, but it'd also prevent us from doing that > in additional places. Which, in my opinion, we really should (and I > believe that's realistically achievable). Thus I really don't want to > base the correctness of CIC - a relatively infrequent operation - on the > assumption that no VM bits can be set concurrenty due to the SUE lock.
I agree. FWIW, the extra time that CIC takes over a plain CI is much reduced these days. -- Peter Geoghegan -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers