The parameter handling for monitors can now be done in a consistent manner
by establishing a rule that the monitor owns the parameter object as long
as it is running. This will allow parameters to be added and removed
safely both from outside and inside monitors.
Currently this functionality is only used by mysqlmon to disable failover
after an attempt to perform a failover has failed.
KILL commands are now sent to the backends in an asynchronous manner. As
the LocalClient class is used to connect to the servers, this will cause
an extra connection to be created on top of the original connections
created by the session.
If the user does not have the permissions to execute the KILL, the error
message is currently lost. This could be solved by adding a "result
handler" into the LocalClient class which is called with the result.
When the LocalClient is constructed, it is possible to extract all the
needed information at that time. The only obstacle is the fact that the
LocalClient is constructed at the same time the session is. Since the
client DCB is created before the session, it is safe to extract the shared
data directly from it.
If a switchover_script parameter is given, its value will be used as
the switchover script. Otherwise the default will be used. Currently
just echo.
The MySQL Monitor now introduces two script variables, CURRENT_MASTER
and NEW_MASTER, that contain information about the current and new
master respectively.
Switchover is performed only if switchover has been enabled and MaxScale
is *not* in passive mode.
The total timeout for the retrying of interrupted queries can now be
configured with the `query_retry_timeout` parameter. It controls the total
timeout in seconds that the query can take.
The actual connection, read and write timeouts of the connector aren't a
good configuration value to use for abstracted queries as the time that it
takes to execute a query can be composed of both connections, reads and
writes. This is caused by the usage of MYSQL_OPT_RECONNECT that hides the
fact that the connector reconnects to the server when a query is
attempted.
The new `query_retries` parameter controls how many times an interrupted
query is retried. This retrying of interrupted queries will reduce the
rate of false positives that MaxScale monitors detect.
To be able to do that, we need to get hold of the MXS_MONITORED_SERVER
corresponding to the SERVER specified as the new master.
So, instead of just return a boolean indicating whether the server was
found or not we return the MXS_MONITORED_SERVER pointer.
The test now skips execution of inserts to separate nodes. This should
guarantee that the nodes are synced at all times.
The test now does the inserts and selects inside a transaction to force
the reads to the same node where the inserts are done.
The tests now print a stack trace to standard output if it receives a
fatal signal. This will help debug test failures caused by broken tests
and unexpected results.
