On 2014-03-31 09:19:12 -0300, Alvaro Herrera wrote: > Andres Freund wrote: > > On 2014-03-31 08:54:53 -0300, Alvaro Herrera wrote: > > > My conclusion here is that some part of the code is failing to examine > > > XMAX_INVALID before looking at the value stored in xmax itself. There > > > ought to be a short-circuit. Fortunately, this bug should be pretty > > > harmless. > > > > > > .. and after looking, I'm fairly sure the bug is in > > > heap_tuple_needs_freeze. > > > > heap_tuple_needs_freeze() isn't *allowed* to look at > > XMAX_INVALID. Otherwise it could miss freezing something still visible > > on a standby or after an eventual crash. > > Ah, you're right. It even says so on the comment at the top (no > caffeine yet.) But what it's doing is still buggy, per this report, so > we need to do *something* ...
Are you sure needs_freeze() is the problem here? IIRC it already does some checks for allow_old? Why is the check for that not sufficient? Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
