On 2014-03-12 20:09:23 -0400, Robert Haas wrote: > On the pgsql-packagers list, there has been some (OT for that list) > discussion of whether commit 9a57858f1103b89a5674f0d50c5fe1f756411df6 > is sufficiently serious to justify yet another immediate minor release > of 9.3.x. The relevant questions seem to be: > > 1. Is it really bad?
It breaks the ctid of concurrently updated/locked tuples during WAL replay. Which can lead to all sorts of nastiness like indexes not finding any rows. Since that kind of locking/updating is pretty common with foreign keys, it's not an unlikely scenario. Unfortunately FPIs won't save the day in all that many scenarios because there'll normally a XLOG_HEAP2_LOCK_UPDATED before the XLOG_HEAP_LOCK record which is replayed badly. Now, one could argue that it only affects replicas or servers that crashed at some point, but I think that's not much comfort. > 2. Does it affect a lot of people or only a few? It's been reported twice (Peter Geoghegan, Greg Stark) by Heroku and one person on IRC could reproduce it repeatedly. The latter was what made me look into it again and find the bug. Greg has confirmed that it fixes the bug when replaying the WAL again. > 3. Are there more, equally bad bugs that are unfixed, or perhaps even > unreported, yet? Uh. I have no idea. I don't know of any reports that can't be attributed to any of these, but as you're also include unreported bugs in that question... 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
