On Thu, Mar 18, 2010 at 9:07 PM, Jeff Davis <pg...@j-davis.com> wrote: > The VM cause wrong results if a bit is set that's not supposed to be -- > right? Am I missing something? How does a seq scan skip visibility > checks and still produce right results, if it doesn't rely on the bit? >
There's also a PD_ALL_VISIBLE flag on the page header. We wal log when we clear that bit so we can trust if it's set then all the tuples really are visible. I forget whether we can trust it if it's *not* set but there's not much point -- all tuples could become visible spontaneously even the page is sitting on disk. -- greg -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
