Hi,
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.
Regards,
Andres