MariaDB 10.4.2 Release Notes
Release date: 29 Jan 2019
MariaDB 10.4 is the current development series of MariaDB. It is an evolution of MariaDB 10.3 with several entirely new features not found anywhere else and with backported and reimplemented features from MySQL.
Do not use beta releases in production!
Thanks, and enjoy MariaDB!
Notable changes of this release include:
- Galera 4 version 26.4.0 has been added in this release, see the Galera 4 Notes section for details
- Account Locking (MDEV-13095)
- a number of bugs related to MDEV-15562 Instant DROP COLUMN have been fixed
- New variable, max_password_errors for limiting the number of failed connection attempts by a user.
- MDEV-17475: Maximum value of table_definition_cache is now
Galera 4 Notes
Upgrading to Galera 4 version 26.4.0
Rolling upgrades from earlier 10.3 (or older) MariaDB releases are not supported in this release. For upgrading a 10.3-based cluster, any applications accessing the cluster should be stopped and the cluster shut down. Then for each cluster node the following procedure should be carried out:
- Install MariaDB 10.4.2 and Galera 4 version 26.4.0
- Start MariaDB server, but make sure it is not trying to connect to the
cluster by configuring
- While MariaDB server is running, run
mysql_upgradefor the server
- Stop MariaDB server
After that, you can bootstrap the cluster. If there was ongoing application load on the cluster during the initial cluster shutdown phase, you should make sure to bootstrap the cluster with the node which was shutdown last.
We are working on rolling upgrade support for the final GA version of MariaDB 10.4. With a rolling upgrade, a live cluster can be upgraded node by node, and the cluster is able to process application load when having a hybrid setup of 10.3 and 10.4 nodes.
New Features in Galera 26.4.0
The ‘mysql’ schema contains new Galera replication related tables:
End users may read but not modify these tables.
The new streaming replication feature allows replicating transactions of unlimited size. With streaming replication, a cluster is replicating a transaction in small fragments during transaction execution. This transaction fragmenting is controlled by two new configuration variables:
wsrep_trx_fragment_unit (bytes, rows, statements)defines the metrics for how to measure transaction size limit for fragmenting. Possible values are:
bytes: transaction’s binlog events buffer size in bytes
rows: number of rows affected by the transaction
statements: number of SQL statements executed in the multi-statement transaction
wsrep_trx_fragment_sizedefines the limit for fragmenting. When a transaction’s size, in terms of the configured fragment unit, has grown over this limit, a new fragment will be replicated.
Transactions replicated through galera replication will now process the commit phase using MariaDB's group commit logic. This will affect transaction throughput, especially when binary logging is enabled in the cluster.
Limitations in Galera 26.4.0
- Upgrading from 10.3 version 25.3.25 to 10.4.2 version 26.4.0 must happen on a stopped cluster. Only after all nodes have been upgraded to MariaDB 10.4.2 and Galera 26.4.0 can the cluster be started up
- Splitting transactions of
LOAD DATAexecution will conflict with streaming replication, and should not be used if streaming replication is configured
Do not use beta releases in production!
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