toast error after pg_upgrade 9.0.4 -> 9.1rc1

After running an essentially uneventful* pg_upgrade from 9.0.4 -> 9.1rc1, we are seeing some toast errors logged on the new cluster:

All are of this pattern: ERROR: missing chunk number 0 for toast value 130087 in pg_toast_34735

Have seen the same pattern for a few of the databases in the 9.1rc1 cluster, and all as a result of a select on a usr table (the offending SELECT happens to be the first one any of these DBs sees, as it's the first step in a user authentication process). SELECT count(*) does not produce an error.

*almost uneventful: We also saw messages that the destination cluster did not have one of our schema - (of course it didn't!) - I didn't realize pg_upgrade doesn't 'do' schema?

Lou Picciano