SQL userdb homedir

I am trying to use a stored procedure in sql for returning the various fields for the user.

I'm concerned about what happens if the stored procedure fails to retrieve the homedir and other fields, for whatever reason. What should it return to notify dovecot of failure ? a single null field, all fields as null, empty result set ?

Thank you​

I am trying to use a stored procedure in sql for returning the various fields for the user.

I'm concerned about what happens if the stored procedure fails to retrieve the homedir and other fields, for whatever reason. What should it return to notify dovecot of failure ? a single null field, all fields as null, empty result set ?

Thank you​