MariaDB 10.4.6 发布了，MariaDB 10.4.6 是一个 GA 稳定版。MariaDB主要由开源社区在维护，采用 GPL 授权许可。
发布日期: 2019.06.18
MariaDB 10.4 是 MariaDB 10.3 的演进版，带来了几个全新功能，并且具有 MySQL 的后端和重新实现的功能。
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.
Galera
Galera 4 version 26.4.0 has been added to MariaDB 10.4
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
wsrep_provider=none - While MariaDB server is running, run
mysql_upgrade for 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:
wsrep_clusterwsrep_cluster_memberswsrep_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 bytesrows: number of rows affected by the transactionstatements: 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 26.4.0
- Upgrading from 10.3 version 25.3.25 to 10.4 version 26.4.0 must
happen on a stopped cluster. Only after all nodes have been upgraded to MariaDB 10.4 and Galera 26.4.0 can the cluster be started up
- Splitting transactions of
LOAD DATA execution will conflict with streaming replication, and should not be used if streaming replication is configured
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'
有关 MariaDB 10.4.6 所做更改的完整列表，请参阅更新日志。 | 
