Congratulations to the MariaDB Foundation for releasing a generally available (GA) stable version of MariaDB Server 10.2! We’ll definitely spend the next few weeks talking about MariaDB Server 10.2, but here’s a quick overview in the meantime. Keep in mind that when thinking about compatibility, this is meant to be the equivalent of MySQL 5.7 (GA: October 21, 2015, with Percona Server for MySQL 5.7 GA available February 23, 2016).
Some of the highlights include:
- Window functions – this is the first release in the MySQL ecosystem that includes Window functions and Recursive Common Table Expression. At the time of this writing, MariaDB hasn’t completed the documentation. It is worth noting that the implementation of Window functions in MariaDB Server 10.2 differs from what you see in MariaDB ColumnStore.
- JSON functions – Many JSON functions to query, update, index and validate JSON. It’s worth noting that MariaDB Server 10.2 does not include a JSON data type as compared to MySQL 5.7). This means you can’t do CREATE TABLE t1 (jdoc JSON) – instead you need to use a VARCHAR or TEXT column. There are also other differences that produce different result sets, and seemingly no column path operator.
- There is also support for GeoJSON functionality, but when we tried ST_AsGeoJSON (yes, documentation needs work), we noticed that the output could vary from MySQL 5.7.
- MyRocks – MariaDB added the hot new storage engine MyRocks as an alpha. You will have to install the MyRocks engine package separably. It isn’t fully merged yet. Watch the umbrella task MDEV-9658.
- SHOW CREATE USER – A new SHOW CREATE USER statement allows you to look at user limitation, as you can now limit users to a maximum number of queries, updates and connections per hour, as well as a maximum number of connections permitted by the user (see setting account resource limits for the MySQL 5.7 equivalent). You’ll want to read the updated documentation around CREATE USER. Don’t be surprised when you see something like “ERROR 1226 (42000): User ‘foo’ has exceeded the ‘max_user_connections’ resource (current value: 1)”. This also is an extension to ALTER USER.
- Flashback – binary log based rollback, aka flashback, can rollback tables and databases to an older snapshot. This should help when the DBA or a user makes an error. This tool works well as long as its a DML statement. This feature came from Alibaba’s AliSQL tree.
- Time delayed replication – new in MariaDB Server 10.2.
- OpenSSL 1.1 – now there is support for OpenSSL 1.1, LibreSSL
- MariaDB Connector/C – most importantly, MariaDB Connector/C replaces libmysql (see: MDEV-9055). This should be API and ABI compatible, but naturally there are some teething problems (see: MDEV-12950).
- Amazon Key Management plugin – from a key management standpoint, the Amazon Key Management plugin is now available to use for encryption. It’s compiled and available as a package. Previously, you had to compile it yourself.
Some of the important things to take note of are:
- As of this release, MariaDB now ships with InnoDB as the default storage engine (as opposed to Percona XtraDB). This means that from here on out, the improvements and fixes to Percona XtraDB won’t necessarily be available in MariaDB. This also means that Percona XtraDB parameters might get ignored (as reported in MDEV-12472).
- In MySQL 5.6+, you can use SHA-256 pluggable authentication. However, this features is still not implemented in MariaDB Server 10.2 (see: MDEV-9804). You can use the ed25519 authentication plugin as a replacement, however.
- When it comes to replication, MySQL 5.7 defaults to row-based replication. MariaDB Server 10.2 defaults to mixed-mode replication (see the discussion around this at MDEV-7635).
- It is worth noting that in order to make MariaDB Server more “Oracle compatible,” DECIMAL now goes up to 38 decimals instead of 30 decimals. MDEV-10138 tells you what happens when you migrate from a long decimal to a default decimal type install (i.e., if you’re moving to another variant in the MySQL ecosystem).
- If you’re familiar with how MySQL 5.7 manages passwords and a new install, the MariaDB Server 10.2 method hasn’t changed.
All in all, this release took a little over a year to make (Alpha was 18 April 2016, GA was 23 May 2017). It is extremely important to read the release notes and the changelogs of each and every release, as MariaDB Server diverges from MySQL quite a bit. At Percona, we will monitor Jira closely to ensure that you always stay informed of the latest changes.