Changes and Improvements in MariaDB 10.4

MariaDB 10.4 is the current major stable version The first stable release was in June 2019, and it will be supported until June 2024.

Implemented Features

Authentication

InnoDB

Optimizer

Syntax

Variables

For a list of all new variables, see System Variables Added in MariaDB 10.4 and Status Variables Added in MariaDB 10.4.

Replication

Galera 4

In MariaDB 10.4.2 and later, Galera has been upgraded from Galera 3 to Galera 4.

Galera 4 Versions

The following table lists each version of the Galera 4 wsrep provider, and it lists which version of MariaDB each one was first released in. If you would like to install Galera 4 using yum, apt, or zypper, then the package is called galera-4.

Galera VersionReleased in MariaDB Version
26.4.2MariaDB 10.4.4
26.4.1MariaDB 10.4.3
26.4.0MariaDB 10.4.2

New Features in Galera 4

The mysql database contains new tables related to Galera replication:

  • wsrep_cluster
  • wsrep_cluster_members
  • wsrep_streaming_log

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_size defines 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 4

Rolling Upgrades from Galera 3 to Galera 4

Rolling upgrades from MariaDB 10.3 (or earlier) to MariaDB 10.4 also require an upgrade from Galera 3 to Galera 4. Galera 4 has a lot of changes and improvements that were not present in Galera 3.

Prior to the General Availability (GA) releases of MariaDB 10.4 and Galera 4, earlier versions of MariaDB 10.4 and Galera 4 had bugs that could lead to problems if Galera 4 nodes were in a cluster with Galera 3 nodes during a rolling upgrade. In these versions, rolling upgrades were not supported. This meant that, in order to upgrade a cluster, the cluster had to be completely stopped, and the nodes could only be restarted after the entire cluster had been upgraded to MariaDB 10.4 and Galera 4.

These bugs have been fixed in more recent versions, and rolling upgrades from Galera 3 to Galera 4 are supported. In order to perform a rolling upgrade, it is recommended to upgrade to MariaDB 10.4.6 or later and Galera 26.4.2 or later. However, as a general rule, users should try to ensure that they are upgrading to the latest versions of MariaDB 10.4 and Galera 4.

For more detailed information on how to upgrade, see Upgrading from MariaDB 10.3 to MariaDB 10.4 with Galera Cluster.

General

  • Crash safe Aria-based system tables (MDEV-16421)
  • Added Linux abstract socket support (MDEV-15655)
  • Enabled C++11 (MDEV-16410)
  • Performance improvements in Unicode collations (MDEV-17534, MDEV-17511, MDEV-17502, MDEV-17474)
  • User data type plugins (MDEV-4912, in progress)
  • Improvements with SQL standard INTERVAL support to help functions TIMESTAMP() and ADDTIME() return more predictable results.
    • Historically, MariaDB uses the TIME data type for both "time of the day" values and "duration" values. In the first meaning the natural value range is from '00:00:00' to '23:59:59.999999', in the second meaning the range is from '-838:59:59.999999' to '+838:59:59.999999'.
    • To remove this ambiguity and for the SQL standard conformance we plan to introduce a dedicated data type INTERVAL that will be able to store values in the range at least from '-87649415:59:59.999999' to '+87649415:59:59.999999', which will be enough to represent the time difference between TIMESTAMP'0001-01-01 00:00:00' and TIMESTAMP'9999-12-31 23:59:59.999999'.
    • As a first step we support this range of values for intermediate calculations when TIME-alike string and numeric values are used in INTERVAL (i.e. duration) context, e.g. as the second argument of SQL functions TIMESTAMP(ts,interval) and ADDTIME(ts,interval), so the following can now be calculated:
SELECT ADDTIME(TIMESTAMP'0001-01-01 00:00:00', '87649415:59:59.999999');
-> '9999-12-31 23:59:59.999999'  

SELECT TIMESTAMP(DATE'0001-01-01', '87649415:59:59.999999')
-> '9999-12-31 23:59:59.999999'  

SELECT ADDTIME(TIME'-838:59:59.999999', '1677:59:59.999998');
-> '838:59:59.999999'  

List of All MariaDB 10.4 Releases

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