The connection counts are now always used to pick the best servers where
the initial connections are created. This covers both master and slaves
selection. Reconnections done while routing queries still pick the "best"
server according to the slave selection criteria. This allows better
servers to be taken into use when `lazy_connect` is enabled.
1. Remove persistence of performance data
2. Move global CanonicalPerformance into SmartRouter object
3. Implement another kill_all_others_v2. Left kill_all_others_v1
in case it should be fixed and used instead.
Does the measurments, usage of the same and persistence to file.
Kill is not implemented, so waits for all clusters to fully responds
The performance data uses a mutex and the persistence data file
is written while holding the mutex. This obviously needs to be
improved, but this commit shows the working concept.
By stopping the REST API before the workers and moving the shutdown to the
same worker that handles REST API requests, we prevent the hang on
shutdown. This also makes the signal handler signal-safe.
If a worker has been stopped, tasks must not be executed on it. To prevent
this, the calling code should check whether the worker has been
stopped. This does not prevent the case where a message is successfully
posted to a worker but the worker is stopped before it processes it.
The slave connection I/O-tread stays running if replication credentials are
wrong when connecting to master. This causes a switchover/failover timeout.
When this happens, print the error in the slave connection status as this
clarifies the problem to the user.
If one slave is executing a query while another one is executing a session
command and the one that is executing the session command fails, the
ongoing query would get retried even though the server that failed was not
executing it. If the server was executing a session command, nothing needs
to be done.
If a resultset is followed by an ERR packet that is not expected
(e.g. server is shutting down), the packet must not be sent to the
client. This allows readwritesplit to replace the failing connection with
a new one thus hiding server shutdowns from clients.
Added range-erase method to mxs::Buffer. This makes it easier to modify
the contents of mxs::Buffer.
The intended use-case for now is to erase unexpected trailing ERR packets
from resultsets.
RWBackend did not expect that a resultset and an unexpected ERR packet
could be stored in the same buffer. This can happen for example if a
server shuts down immediately after the resultset is sent.
With this change, a parenthesized top-level SELECT, such as
"(SELECT f FROM t)" will be fully parsed. Before this change,
the statement was classified as invalid and would thus have
been sent to the master.
With this change also statements like
(SELECT f FROM t1) UNION (SELECT f FROM t2)
will be correctly classified, although only partially parsed.
