BTW, what should our advice be for recovering from corruption due to
this bug? As far as the btree and GIN problems go, we can tell people
that REINDEX will fix it. And in 9.1, you don't really need to worry
about the visibility map being bad. But what do you do in 9.2, if
you have a bad visibility map? Is there any fix short of VACUUM FULL?
regards, tom lane