What is MariaDB 10.2?

MariaDB 10.2 is the current major development version.

The following lists the major new features in MariaDB 10.2:

Implemented Features

Syntax

• Window functions have been introduced.
• The SHOW CREATE USER statement was introduced.
• New CREATE USER options for limiting resource usage and tls/ssl.
• New ALTER USER statement.
• New WITH statement. WITH is a common table expression that allows you to refer to a subquery expression many times in a query. (MDEV-8308 & MDEV-9864)
• Support for CHECK CONSTRAINT (MDEV-7563).
• Support for DEFAULT with expressions (MDEV-10134).
• BLOB and TEXT fields can now have a DEFAULT value.
• Lots of restrictions lifted for Virtual computed columns.
• Number of supported decimals in DECIMAL has increased from 30 to 38. (MDEV-10138)
• Multiple triggers for the same event (MDEV-6112)
• Added catchall for list partitions (MDEV-8348)

Information Schema

• An information schema plugin to report all user variables, which creates the Information Schema USER_VARIABLES Table - MDEV-7331.

EXPLAIN

• EXPLAIN FORMAT=JSON now shows outer_ref_condition field which contains the condition that the(?) SELECT checks on each re-execution - MDEV-9652.
• EXPLAN FORMAT=JSON now shows sort_key field which shows the sort criteria used by filesort operation. (commit 2078392)

• EXPLAIN used to show incorrect information about how the optimizer resolved ORDER BY clause or Distinct. This was a long-standing problem with roots back in MySQL. Now, after MDEV-8646 and related fixes, the problem doesn't exist anymore. (For test cases, see MDEV-7982, MDEV-8857, MDEV-7885, MDEV-326)

Optimizations

• Connection setup was made faster by moving creation of THD to new thread (MDEV-6150)

Compatibility

• NO PAD collations, which means that end space are significant in comparisons (MDEV-9711)

Variables

For a list of all new variables, see System Variables Added in MariaDB 10.2 and Status Variables Added in MariaDB 10.2. These include:

• aria_recover has been renamed to aria_recover_options - MDEV-8542.
• The server version can now be faked to work around dated applications that require a particular version string - MDEV-7780
• slave_parallel_workers is now an alias for slave_parallel_threads.
• New status variables com_alter_user, com_multi and com_show_create_user.
• New variable for setting a directory for storing temporary non-tablespace InnoDB files, innodb_tmpdir.

Scripts

• Continuous binary log backup has been added to mysqlbinlog - MDEV-8713.
• mysql_zap and mysqlbug have been removed - MDEV-7376, MDEV-8654.

Code

• "fast mutexes" have been removed. These aren't faster than normal mutexes, and have been disabled by default for years - MDEV-8111.

List of all MariaDB 10.2 releases

See also

• Plans for 10.x for features under consideration.
• 10.2 Features/fixes by vote (JIRA)