I know that I have at least one instance of a varchar that is not valid UTF-8, imported from a source with errors (AMA CPT files, actually) before PG's checking was as stringent as it is today. Can anybody suggest a query to find such values?
I hit this problem too, if I remember correctly when trying to upgrade a database from 8.3 to 8.4. I ended up aborting the upgrade, since the upgrade documentation made no mention of this and I didn't have time to dig into it at the time. A tool to find all instances of this would be very helpful.
