Dave Peticolas <dave(at)krondo(dot)com> writes:
>>> I'm seeing this error on a table repeatedly:
>>> found update xid 3433096759 from before relfrozenxid 3498422955
>> This is a primary, 9.6.8 to be exact.
This message is known to be associated with several data-corruption bugs
we've fixed recently. You should update to current (9.6.10) sooner not
later. I don't think that will cure existing corruption for you, but
it should prevent things from getting worse.
regards, tom lane