Hi all,
To satisfy my own curiosity, I was trying to find where 8.4 kicks into a backwards scan of the data file during (auto-)vacuuming.
This appears to be repair_frag() in backend/commands/vacuum.c, but only appears to be called by a FULL vacuum. Autovacuum, however, appears to explicitly only ever call a not-FULL vacuum, so I'm trying to see where and how it would be possible for autovacuum to trigger this operation. Any pointers?
Thanks,
Tom