Updated the README to point to various documents that help set up
MaxScale. Also removed the somewhat incorrect information about the
technical implementation details.
Before the state of the backend servers is checked, MaxScale needs to be
stopped to prevent the automated failover from interfering in the start-up
process.
If a service has no active servers and users are injected, a warning would
be logged. This is a misleading warning if the service has no servers and
should only be logged if the failure to load any users is an unexpected
situation.
The log manager is the only one that uses the mlist_t versioned list. The
counter that keeps track of the version number was not modified using
atomic operations meaning that the compiler is free to optimize away parts
of the lock-free versioning mechanism that uses it.
To prevent this optimization, the variable is declared volatile. A rewrite
is direly needed but it cannot be done in 2.2.
Displaying the MaxScale version helps identify which package the
executable was bundled with. As the MaxCtrl source is a part of MaxScale,
there's no need for separate versioning.
Removed the excessive comments in favor of a simplified description. Use
stack-allocated TestConnections and simplify assertions.
The main change is the different SQL used to update the user with the old
password. Direct modification of the `mysql`.`user` database isn't very
neat but it guarantees that the value is updated.
The test should stop MaxScale at the start unless the manual debug flag is
given on the command line. This fixes the connection failure of mxs1719
but reveals a problem with the filter itself.
Due to the skewed accept distribution without SO_REUSEPORT, we use
round-robin assignment of workers for new client connections. This
provides better performance as work is more likely to be evenly
distributed across all threads.
Using a least-busy-worker algorithm would provide a more stable result but
this is not trivially simple to implement. For this reason, the
round-robin based approach was chosen for 2.2.
Parameters that accept whitespace-only values need to have their default
values quoted if they contain only whitespace characters. In 2.2 the
qlafilter is the only module that did not do this.
When a test is checking the status of the nodes, the output is relatively
verbose.
Also changed dropping of users to use the IF EXISTS syntax. This will
remove the errors if the users do not exist.
When a valid target was not found, no error message was logged by the
router. This would cause the "Routing the query failed. Session will be
closed." message to be logged with no explanation as to why the routing
failed.
In addition to the above-mentioned case, no message would be logged if the
target for a COM_STMT_FETCH was not in use.
If the authentication failure was due to a missing database, this extra
information can be logged. This will help cases where users are using
databases that do not exist.
If only one server is used, the amount of requests can be reduced from a
minimum of two to a minimum of one. In most cases this cuts down the
response time in half.
Also change the following defaults:
- "selects": Was "verify_cacheable", is now "assume_cacheable"
- "cached_data": Was "shared", is now "thread_specific"
Don't test failover functionality when it is not needed. The bug is only
about the extra events that appear when a master is demoted and a slave is
promoted.
Prepared statements via readwritesplit need to have their IDs mapped from
the internal representation to the backend specific one. The RWBackend
class does this in its write method but the fix in commit
e561c3995c7396cf3749ccdf6a3357d7dd32c856 caused this to be bypassed and
the base version was always used.
If a session command produces a different result on the slave than it did
on the master, a warning is logged. This warning now also logs the query
that was being executed to make investigation of the problem easier.
Backend::execute_session_command would use the overridden write method
instead of the Backend::write method that it intended to use. This caused
session commands that did not expect a response to be in a state that
expected a result.
Also fixed RWBackend::write pass the response_type value to
Backend::write.
Going the belt-and-suspenders way of both sleeping and waiting for the
moitor should make sure MaxScale has at least some time to start up, query
the servers and do a single iteration of monitoring.
