When a read-only transaction fails due to a connection error, no message
would be logged. Also added an info level message for the case when a
backend connection would get closed before the session is in the correct
state and a debug assertion that the router session should never be closed
when the handleError method is called.
The removing and slave status updating is now separated to a function.
As the MariaDBServer object now contains the updated slave connections,
keeping track of removed connections is no longer required.
The two cases are now separated. In switchover, the promotion and
demotion targets can swap connections between each other without worry.
In failover, the two connection lists must be merged semi-intelligently.
The slave connections of the two servers are now saved to the operation
descriptor object at the start of the operation. This allows slave status
updating during the operation.
This prevents some questionable status assignments, but also means that
the Relay Master status can be lost if a slave goes down. This is
contrary to Master status which is not lost if slaves go down. Fixes
mxs1961_standalone_rejoin.
The binlogrouter uses buffers across worker threads which is no longer OK
in 2.3. The correct solution would be to store data in something other
than a GWBUF (e.g. std::vector) and protect the sharing with a mutex. The
current solution simply works around the assertions by using macros
instead of functions.
Several small changes:
Binlog is flushed at the end of old master demotion.
Only new master is required to catch up to old master.
Use the same replication check method as failover.
By biasing the values of all counter type scores to positive integers, the
server weights are always taken into use.
This fixes the case when weights were ignored until all score base values
were larger than zero (the mxs922_server test).
If the DCB is closed in handleError, it would be NULL in closeSession. To
only close the DCB in one place, the handleError can be reduced to writing
an error to the client and marking the failure as a fatal one.
No longer writes events to the master, as this creates problems if the
promoted server was not the overall master. Instead, the slave status
output is inspected.
Clean up, comments and enhancements. StopWatch lap() didn't mean lap-time, but elapsed time. Changed meaning to lap-time and added split() for split-time.
The check for a closed session should never be needed as the core
correctly orders the calls to the module functions. The version numbering
was also not used.
Fixed the incrementation of the query counter so that it uses relaxed
atomic operations.
Replaced SPINLOCK with std::mutex where possible, leaving out the more
complex cases. The big offenders remaining are the binlogrouter and the
gateway.cc OpenSSL locks.
In progress, does not yet overwrite existing code.
The new promotion mechanism automatically retries queries which timed out. It also
handles multimaster situations correctly.
Removed the almost equal comparison and subsequent selection based on historical number of connections.
The effect of it was this: Select the server that has historically, weights or not, been slower. Tested this with 2.2
with maxscale on one server and mariadb:s on two servers with different network lags. The tests with historical
selects were clearly slower.
