Based on MySQL 5.5.32, including all the bug fixes in it, Percona Server 5.5.32-31.0 is now the current stable release in the 5.5 series. All of Percona‘s software is open-source and free, all the details of the release can be found in the 5.5.32-31.0 milestone at Launchpad.
Percona Server has implemented support for supplementary groups for PAM Authentication Plugin.
Prevented a race condition that could lead to a server crash when querying the INFORMATION_SCHEMA.INNODB_BUFFER_PAGE table. Bug fixed #1072573.
Querying INFORMATION_SCHEMA.PARTITIONS could cause key distribution statistics for partitioned tables to be reset to those corresponding to the last partition. Fixed the upstream bug #69179. Bug fixed #1192354.
Incorrect schema definition for the User Statistics tables in INFORMATION_SCHEMA (CLIENT_STATISTICS, INDEX_STATISTICS, TABLE_STATISTICS, THREAD_STATISTICS, and USER_STATISTICS) led to the maximum counter values being limited to 32-bit signed integers. Fixed so that these values can be 64-bit unsigned integers now. Bug fixed #714925.
Fixed the upstream bug #42415 that would cause UPDATE/DELETE statements with the LIMIT clause to be unsafe for Statement Based Replication even when ORDER BY primary key was present. Fixed by implementing an algorithm to do more elaborate analysis on the nature of the query to determine whether the query will cause uncertainty for replication or not. Bug fixed #1132194.
When an upgrade was performed between major versions (e.g. by uninstalling a 5.1 RPM and then installing a 5.5 one), mysql_install_db was still called on the existing data directory which lead to re-creation of the test database. Bug fixed #1169522.
Missing path separator between the directory and file name components in a bitmap file name could stop the server starting if the innodb_data_home_dir variable didn’t have the path separator at the end. Bug fixed #1181887.
Fixed the upstream bug #68354 that could cause server to crash when performing update or join on Federated and MyISAM tables with one row, due to a bug in the Federated storage engine. Bug fixed #1182572.
Under very rare circumstances, deleting a zero-size bitmap file at the right moment would make server stop with an I/O error if changed page tracking is enabled. Bug fixed #1184517.
Transaction objects are now allocated calling calloc() directly instead of using InnoDB heap allocation. This may improve write performance for high levels of concurrency. Bug fixed #1185686.