On Fri, Apr 1, 2011 at 11:18 AM, Bruce Momjian <br...@momjian.us> wrote: > Robert Haas wrote: >> Oh, quite right. Sorry I missed that. I suppose if we wanted to fix >> this for real, we'd want to get: >> >> 105->5 >> 104->4 >> 103->3 >> 102->max_xid >> 101->max_xid-1 >> 100->max_xid-2 >> 99->max_xid-3 >> 98->max_xid-4 >> >> But it doesn't seem worth getting excited about. > > I think (?) the problem with that is the every time you wrap around you > get more out of sync. :-O
It's not clear to me that it matters a bit, though. > Thinking more, the problem is that when the xid counter wraps around > from max_xid to 3, we jump the freeze horizon by three, e.g 5000 to > 5003. So when, the freeze horizon wraps, we can either have that jump > by three, e.g set it to FirstNormalTransactionId, or delay by three, > e.g. set it to MaxTransactionId. So what? :-) -- 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
