The release of the database management system MariaDB 12.2.2 has been published, marked as the first stable release of branch 12.2. The MariaDB 12.2 branch is classified as a rolling release, continues the gradual development of functionality, and replaces the MariaDB 12.1 branch. At the same time, MariaDB 12.3.1 has been released with a new implementation of binlog, which has the status of a release candidate for the future LTS branch. The MariaDB 12.2 branch will be supported until the release of 12.3.2.
The MariaDB project develops a fork from MySQL, preserving backward compatibility and distinguished by the integration of additional storage engines and enhanced capabilities. The development of MariaDB is overseen by the independent MariaDB Foundation in accordance with an open and transparent development process that is not dependent on individual vendors. MariaDB is supplied instead of MySQL in many Linux distributions (RHEL, SUSE, Fedora, openSUSE, Slackware, OpenMandriva, ROSA, Arch Linux, Debian) and is implemented in major projects such as Wikipedia, Google Cloud SQL, and Nimbuzz.
Among the changes in the MariaDB 12.2 branch:
- In compatibility mode with Oracle database management systems, the functions TO_NUMBER (converting a string to a number) and TRUNC (truncating a date, for example, to the hour, day, month, year) have been implemented.
- An optimization has been implemented during table merge operations (JOIN), taking into account the uniqueness of rows in subqueries with the 'GROUP BY' expression for more accurate forecasting of the number of resulting rows (out_rows) and correct index application.
- New options for managing the optimizer ROWID_FILTER/NO_ROWID_FILTER and INDEX_MERGE/NO_INDEX_MERGE have been added, as well as the ability to implicitly specify block names in queries (optimization options can be selectively applied to parts of queries by referencing them with names like 'select#N', where N is the sequential number of the block). For example: 'select /*+ JOIN_ORDER(@"select#2" twenty,ten) */ ....'.
- The limitations on the level of nesting of structures in functions for working with JSON have been lifted (the JSON_DEPTH_LIMIT, which previously had a value of 32, has been removed).
- A table TRIGGERED_UPDATE_COLUMNS has been added to the INFORMATION_SCHEMA schema (INFORMATION_SCHEMA.TRIGGERED_UPDATE_COLUMNS), showing the columns modified when a trigger is fired.
- In the PARAMETERS table within the INFORMATION_SCHEMA schema, a PARAMETER_DEFAULT column has been implemented, containing default values for stored procedure parameters.
- Experimental support for the 'CREATE GLOBAL TEMPORARY TABLE' expression has been implemented for creating global temporary tables. Such temporary tables are deleted after the session ends and are visible to all users but contain data unique to each user.
- In testing mode, improved support for replication between tables with different structures has been proposed.
Source: opennet.ru
