Hi, We've had bugs in pg_upgrade where post-upgrade xid horizons weren't correctly set. We've had bugs were indexes were corrupted during replay.
The latter can be caught by wal_consistency_checking - but that's pretty expensive. It seems $subject would have a chance of catching some of these bugs, as well as exposing amcheck to a database with a bit more varied content? Depending on the cost it might make sense to do this optionally, via PG_TEST_EXTRA? Greetings, Andres Freund
