Recently, my blog posts suddenly started appearing in reverse order.
This is due to a known problem related to a known bug in MySQL. The solution is to upgrade MySQL to a newer version. Unfortunately, there ARE NO newer GA releases to upgrade to!
See http://wordpress.org/support/topic/154622.
Seeing this level of bug in a GA release is, IMO, nearly inexcusable. It really makes me question what is going on with MySQL. Could it be related to Sun’s takeover of MySQL? It certainly puts a black mark on MySQL’s reliability in my book.
After looking into the MySQL bug a bit further I’ve come to realize it’s not quite as severe as it seemed at first. The bug only occurs when doing a GROUP BY on the primary key of a table, which is pointless anyway. WordPress shouldn’t have been doing it. So I went in and hacked my WordPress installation to fix the problem. I posted my solution here.