The `global` parameter causes the time window defined by the `time`
parameter to be applied at the instance level instead of the session
level. This means that a write from one connection will cause all other
connections to use the master for a certain period of time.
Using a configurable time window for consistency is not good as it is not
absolute and cannot adjust to how servers behave.
One example that demonstrates this is when a slave is normally lagging
behind by less than a second but some event causes the lag to spike up to
several seconds. In this case the configured time window would no longer
guarantee consistency.
Another reason to avoid a "static" time window is the fact taht it
prevents load balancing in the cases where slaves catch up to the master
within time window. This happens when time is configured to a higher value
to avoid inconsistencies at all costs.
Added a test case that verified the feature works.
The test case covers a few bugs that were fixed by the previous
commits. The first part of the test covers the case when master
reconnection fails while session command history is being executed. The
second part of the test makes sure exceeding the session command history
will prevent master reconnections from taking place.
Certain MariaDB connectors will use the direct execution for batching
COM_STMT_PREPARE and COM_STMT_EXECUTE execution without waiting for the
COM_STMT_PREPARE to complete. In these cases the COM_STMT_EXECUTE (and
other COM_STMT commands as well) will use the special ID 0xffffffff. When
this is detected, it should be substituted with the ID of the latest
statement that was prepared.
Very simple, creates 10 threads that concurrently starts making
simple INSERTs and SELECTs. The purpose is to test that the basic
router to router mechanism of smartrouter works.
The test performs the following:
CREATE tbl (x INT PRIMARY KEY)
t1 t2
BEGIN BEGIN
INSERT INTO tbl VALUES (1)
SELECT * FROM tbl FOR UPDATE
That will cause t2 to wait.
INSERT INTO tbl VALUES (0)
That will cause t2 to be rolled back due to a deadlock.
Without transaction replay, the SELECT will return with an error.
With transaction replay, the deadlock error will be caught, the
transaction replayed and SELECT will return successfully.
Before the MXS-2250 fix, the following ends with an error:
CREATE TEMPORARY TABLE t (f INT);
DESCRIBE t;
Reason is that the first is sent to the master (and the table will
not be replicated to slaves) and the latter to some slave.
The bug appears when a session command that is executed on the master
fails. The logic in the code doesn't take this case into consideration
when it processes failed connections.
The purpose of this class is to make it easy from a test program
to access the output of the REST-API. Currently it provides only
the equivalent of "maxctrl list servers", but it can be extended
if and when additional needs arise.
Right now it's implemented so that curl is executed on the 0th
MaxScale instance, using the ssh mechanism of the test framework.
Added a test that makes sure the transaction replay cap is respected. Also
improved the logging to show how many transaction replay attemps have been
done and to log if a replay is not done due to too many attempts.
