[loadzero]

A) Continuous triggers are implemented by using the logical replication features of Postgres. This means that changes are consumed from a queue and evaluated in a separate process to the rest of the system. A long running trigger will block the trigger process only.

B) We do re-use quite a bit of the standard trigger mechanisms, but we wanted to use our own evaluation context to support extra features. For example, continuous triggers can be defined on sliding windows, which require the trigger to be evaluated over multiple transformed tuples in the underlying table.