To support a wider range of client connectors, MaxScale should respond
with an AuthSwitchRequest packet to all COM_CHANGE_USER commands. Only
MariaDB connectors understand the OK packet as the only response to a
COM_CHANGE_USER but all connectors understand the AuthSwitchRequest
packet.
The current command needs to be updated before the queries are actually
routed. This allows the KILL command detection and processing to correctly
work.
With the configuration entry
dump_last_statements=[never|on_close|on_error]
you can now specify when and if to dump the last statements
of of a session.
With the configuration entry
retain_last_statements=<unsigned>
or the debug flag '--debug=retain-last-statements=<unsigned>',
MaxScale will store the specified number of last statements
for each session. By calling
session_dump_statements(session);
MaxScale will dump the last statements as NOTICE messages.
For debugging purposes.
By always starting the session shutdown process by stopping the client
DCB, the manipulation of the session state can be removed from the backend
protocol modules and replaced with a fake hangup event.
Delivering this event via the core allows the actual dcb_close call on the
client DCB to be done only when the client DCB is being handled by a
worker.
If a DCB is closed before a response to the handshake packet is received,
the DCB's session will point to the dummy session. In this case no error
should be written to the DCB.
