* Anomalies around use of CURRENT_TIMESTAMP are not discussed or resolved. Probably need to add a test that end_timestamp > start_timestamp or ERROR, which effectively enforces serializability.
This scenario doesn't happen. There are no possibility of a record being deleted or updated before inserting
* No discussion, comments or tests around freezing and whether that causes issues here
This feature introduced no new issue regarding freezing. Adding
the doc about the table size growth because of a retention of old record seems
enough for me
* ALTER TABLE needs some work, it's a bit klugey at the moment and needs extra tests. Should refuse DROP COLUMN on a system time column, but currently doesn't
* UPDATE foo SET start_timestamp = DEFAULT should fail but currently doesn't
