Dirk Lutzebaeck <lutzeb(at)aeccom(dot)com> writes:
> cs=> select envelope from recipient where envelope=510349;
> [ returns a tuple that obviously fails the WHERE condition ]
Yipes. Do you have an index on the envelope field, and if so is
it being used for this query? (Use EXPLAIN to check.) My guess
is that the index is corrupted. Dropping and recreating the index
would probably set things right.
Of course the real issue is how it got corrupted. Hiroshi found
an important bug in btree a few days ago, and there is a discussion
going on right now about lock-manager bugs that might possibly allow
multiple backends to corrupt data that they're concurrently updating.
But I have no idea if either of those explains your problem.
regards, tom lane