abort   the Unix abort function is called, and a core file is generated.

default   the database server behaves in the same manner as abort in all cases, except when a device-full fatal error occurs. In this case, it behaves in the same manner as defunct. This action prevents the system from trying to write a core file on a full device. This is the default behavior.

defunct   the database server continues running and does not call abort. Any new connection attempts made to the database server receive the SQL error of the original fatal error.