Not updating powerdns disabled in etcdefaultpdns
All slaves for this domain must receive a notification but the nameserver only knows the names of the slaves - not the IP addresses, which is where the problem lies.
In contrived configurations this may lead to duplicate notifications being sent out, which shouldn't hurt.
Some backends may be able to detect zone changes, others may chose to let the operator indicate which zones have changed and which haven't.
Consult the documentation for your backend to see how it processes changes in zones.
My SQL configured with either Berkeley DB or Inno DB meets this requirement, as do Postgre SQL and Oracle.
The Bindbackend implements transaction semantics by renaming files if and only if they have been retrieved completely and parsed correctly.