http://search.cpan.org/perldoc/Log::Log4perl::FAQ#How_can_I_configure_Log::Log4perl_to_send_me_email_if_something_happens?
log4perl.appender.Mailer = Log::Dispatch::Email::MailSend
log4perl.appender.Mailer.to = drone@example.net
log4perl.appender.Mailer.subject = Something's broken!
log4perl.appender.Mailer.layout = SimpleLayout

Its unclear from the documentation when the email is sent, but its not immediately

In reply to Re: log4perl collecting (buffering) messages (Log::Log4perl::FAQ) by Anonymous Monk
in thread log4perl collecting (buffering) messages by coke4all

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