Yes, this is a nice feature. However, without the DirtySnapshot index scan fix, it will fail in numerous instances, especially in master-master replication.

The update_missing feature is helpful in this case, but it is still not the correct event because a real tuple exists, and we should receive update_differ instead. As a result, some conflict resolution systems may malfunction. For example, if the resolution method is set to apply_or_skip, it will insert the new row, causing two rows to exist. This system is quite fragile, and I am sure there are many more complicated scenarios that could arise.