Robert Haas <robertmh...@gmail.com> writes: > On Tue, Oct 18, 2016 at 5:37 AM, Amit Kapila <amit.kapil...@gmail.com> wrote: >> I have implemented this idea and it works for MVCC scans. However, I >> think this might not work for non-MVCC scans. Consider a case where >> in Process-1, hash scan has returned one row and before it could check >> it's validity in heap, vacuum marks that tuple as dead and removed the >> entry from heap and some new tuple has been placed at that offset in >> heap.
> Oops, that's bad. Do we care? Under what circumstances would a hash index be used for a non-MVCC scan? regards, tom lane -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers