Based on MySQL 5.5.28, including all the bug fixes in it, Percona Server 5.5.28-29.2 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 5.5.28-29.2 milestone at Launchpad.
Multiple bitmap file support for XtraDB changed page tracking has been implemented.
Percona Server now has an option to build the binary tarball with enabled debugging. New flag --dubug has been added to the build script, that will create a build with the debug-enabled binaries. New binaries will have -debug appended in case it is a debug build, ie. mysqld-debug.
HandlerSocket has been updated to version 1.1.0 (rev. 83d8f3af176e1698acd9eb3ac5174700ace40fe0).
innochecksum has been extended with an option to read file format information from a given InnoDB data file. As only the first page needs to be read to detect the format/version information, it can also be used on a running server. This information can be useful when doing the Expand Table Import.
Support for Fake Changes has been improved by fetching the sibling pages.
Fast InnoDB Checksum feature has now been deprecated.
Fixed the package dependencies for CentOS 6, that caused conflicts during the install. Bug fixed #908620 (Ignacio Nin).
Although fake change transactions downgrade the requested exclusive (X) row locks to shared (S) locks, these S locks prevent X locks from being taken and block the real changes. This fix introduces a new option innodb_locking_fake_changes which, when set to FALSE, makes fake transactions not to take any row locks. Bug fixed #1064326 (Mark Callaghan, Laurynas Biveinis).
Fake changes were increasing the changed row and userstat counters. Bug fixed #1064333 (Laurynas Biveinis).
Log tracking was initialized too late during the InnoDB startup. Bug fixed #1076892 (Laurynas Biveinis).
There is no need to scan buffer pool for AHI entries after the B-trees for the tablespace have been dropped, as that will already clean them. Bug fixed #1076215 (Laurynas Biveinis).
Slow Query Log code did not handle the case of individual statements in stored procedures correctly. This caused Query_time to increase for every query stored procedure logged to the slow query log. Bug fixed #719386 (Alexey Kopytov).