Hallo Costin,
Thanks for your reply. The standard Hive behaviour with internal tables (certainly with partitions) is that Hive empties the target location/partition and writes the new data afresh. With EXTERNAL TABLES that is a grey area as the data does not strictly "belong" to Hive, so I can understand why a delete does not happen (I would think the most elegant implementation would be to control this behaviour via a property, as is done with e.g.'es.index.auto.create', although DELETEs are there in Hive 0.14).
But at least I know that is expected behaviour! Thanks for your help.
Andrew