Frank van Vugt <ftm(dot)van(dot)vugt(at)foxi(dot)nl> writes:
> FYI, it's a plain v8.1 with the given patch on autovacuum.c and an earlier
> patch from Tom for the distinct bug which only touches ExecMain.c and
> ExecUtils.c
Hm, I'm wondering if the toast-vs-index bug could be relevant. Could
you try 8.1 branch tip? Or at least apply this patch:
http://archives.postgresql.org/pgsql-committers/2005-11/msg00439.php
regards, tom lane