Up until 2.1.12, if it in the configuration file said
'router_options=slave', the master was used if there were no
slaves at session creation time.
That broke in 2.1.13 as a side-effect of MXS-1516 that checks
at routing time whether the server initially selected as master
still is the master.
Now the required server status is stored separately for each
session, so that if the master was chosen, even though we have
'router_options=slave', we can turn on the SERVER_MASTER bit.
That allows us to handle the case correctly in connection_is_valid().
The safest way to stop the avrorouter is to stop replication and wait for
the conversion to halt. This was not previously documented and needs to be
mentioned in the router documentation.
Added the `transaction_replay_max_size` parameter that controls the
maximum size of a transaction that can be replayed. If the limit is
exceeded, the stored statements are released thus preventing the
transaction from being replayed.
This limitation prevents accidental misuse of the transaction replaying
system when autocommit is disabled. It also allows the user to control the
amount of memory that MaxScale will use.
The transaction retrying behavior is now configurable and documented. The
`transaction_replay` parameter implicitly enables the required
functionality in the router that it needs.
Enabling the session command history but limiting it to a history of 50
commands allows reconnections for sessions that don't change the state too
often.
As pooled connections will exceed this limit quite fast, they are not able
to reconnect to servers once connections are lost. To solve this problem,
the session command history needs a compaction process that removes
redundant history.
As they are deprecated, they should not be mentioned in the examples. Also
moved the router_options documentation under a Legacy Configuration
heading.
With the `allow_master_change` parameter enabled, sessions can start using
a different master node if one is available. This will not prevent
sessions from closing if a write query is received while no master
replacement is available.
The `purge` command can be used to reset the conversion
process. Currently, executing the `purge` module command and restarting
MaxScale is the only correct way to reset the conversion process.
The default value for strict_multi_stmt prevents compound statements and
atomic multi-statement commands from being executed without completely
disabling load balancing. As the new default value will have no practical
effect on all correct uses of readwritesplit, this is a relatively safe
thing to change.
Updated all examples to use parameters instead of router_options. Added a
more clear note about router_options being deprecated. Removed unnecessary
parameters from all examples.
The transaction safety was checked even if master GTID registration was
disabled. This always caused a failure when the router was started without
the transaction safety parameter.
As transaction safety is required by the GTID registration, it is not very
helpful to refuse to start if an invalid set of options is detected. To
make usage of the master GTID registration easier, the transaction safety
is also automatically enabled.
The documentation stated that the binlogrouter would use the cache
directory to store the binary log files. In reality, there was no default
value and the service would fail to start without a binlogdir parameter.
The router now uses the data directory (/var/lib/maxscale/) to store the
binary logs.
Set the default value of mariadb10-compatibility to true. This is in line
with the fact that most installations should use the router with a MariaDB
10.0 server or newer.
