On Sat, Jun 1, 2013 at 2:48 PM, Heikki Linnakangas <hlinnakan...@vmware.com> wrote: >> We define a new page-level bit, something like PD_RECENTLY_FROZEN. >> When this bit is set, it means there are no unfrozen tuples on the >> page with XIDs that predate the current half-epoch. Whenever we know >> this to be true, we set the bit. If the page LSN crosses more than >> one half-epoch boundary at a time, we freeze the page and set the bit. >> If the page LSN crosses exactly one half-epoch boundary, then (1) if >> the bit is set, we clear it and (2) if the bit is not set, we freeze >> the page and set the bit. > > Yep, I think that would work. Want to write the patch, or should I? ;-)
Have at it. I think the tricky part is going to be figuring out the synchronization around half-epoch boundaries. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers