On Tue, 2008-10-14 at 18:50 +0100, Simon Riggs wrote: > I've worked out what I think is a workable, efficient process for > deriving snapshots during recovery. I will be posting a patch to show > how this works tomorrow [Wed 15 Oct], just doing cleanup now.
How will this interact with an idea like this?: http://archives.postgresql.org/pgsql-hackers/2008-01/msg00400.php > I've had to change the way XidInMVCCSnapshot() works. We search the > snapshot even if it has overflowed. This is actually a performance win > in cases where only a few xids have overflowed but most haven't. This is > essential because if we were forced to check in subtrans *and* > unobservedxids existed then the snapshot would be invalid. (I could have > made it this way *just* in recovery, but the change seems better both > ways). I don't entirely understand this. Can you explain the situation that would result in an invalid snapshot? Regards, Jeff Davis -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
