What is MariaDB 5.5

MariaDB 5.5 is mostly MariaDB 5.3 + MySQL 5.5, with a few added features.

Feature Comparison Matrix

We have created an Optimizer Feature Comparison Matrix showing the new optimizer features in MariaDB 5.5 and 5.3 compared to MySQL 5.5 and 5.6.

New features

• Significantly more efficient thread pool, comparable in functionality to the closed source feature in MySQL Enterprise.
• Non-blocking client API Library (MWL#192)
• @@skip_replication option (MWL#234)
• SphinxSE updated to version 2.0.4.
• "extended keys" support for XtraDB and InnoDB
• New INSTALL SONAME statement
• New LIMIT ROWS EXAMINED optimization.
• mysql_real_connect() Changes
  • In MySQL, and in MariaDB versions before 5.5.21, mysql_real_connect() removes from the MYSQL object any options set with mysql_option() when it fails. Beginning with MariaDB 5.5.21, options are preserved by a failing mysql_real_connect(); use mysql_close(), as normal, to clear them.
  • This only has effect if the MYSQL object is reused after a mysql_real_connect() failure (which is unusual). No real-life incompatibilities are expected from this change (it is unlikely that an application would rely on options being automatically removed between connection attempts).
• The variables replicate_do_*, replicate_ignore_*, and replicate_wild_* have been made dynamic, so they can be changed without requiring a server restart. See Dynamic Replication Variables for more information.

• The new plugin to log SQL level errors. SQL_ERROR_LOG

Minor extensions

• Updates to performance schema tables are not stored in binary log and thus not replicated to slaves. This is to ensure that monitoring of the master will not cause a slower performance on all slaves. This also fixes a crash on the slaves.

New features are added to MariaDB 5.6.

Deprecated / disabled features

• PBXT is not anymore in the binary builds/distributions. It's however still in the source distributions and in the source tree. The reason is that PBXT is not actively maintained anymore, it has a few bugs that are not fixed and it's not that much in use.