Based on MySQL 5.5.34, including all the bug fixes in it, Percona Server 5.5.34-32.0 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 5.5.34-32.0 milestone at Launchpad.
Percona Server has extended the SELECT INTO ... OUTFILE and SELECT INTO DUMPFILE to add the support for UNIX sockets and named pipes.
Percona Server now provides additional information in the slow query log when log_slow_rate_limit variable is enabled.
A new variable slow_query_log_always_write_time has been introduced. It can be used to specify an additional execution time threshold for the slow query log, that, when exceeded, will cause a query to be logged unconditionally, that is, log_slow_rate_limit will not apply to it.
Due to an incompatible upstream change that went in unnoticed, the log tracker thread would attempt to replay any file operations it encountered. In most cases this were a no-op, but there were race conditions for certain DDL operations that would have resulted in server crash. Bug fixed #1217002.
apt-get upgrade of Percona Server would fail in post-installation step if server failed to start. Bug fixed #1002500.
Fixed the libssl.so.6 dependency issues in binary tarballs releases. Bug fixed #1172916.
Error in install_layout.cmake could cause that some library files, during the build, end up in different directories on x86_64 environment. Bug fixed #1174300.
The unnecessary overhead from persistent InnoDB adaptive hash index latching has been removed, potentially improving stability of the Multiple Adaptive Hash Search Partitions feature as well. Upstream bug fixed #70216, bug fixed #1218347.
Building Percona Server with -DHAVE_PURIFY option would result in an error. Fixed by porting the close_socket function from MariaDB. Bug fixed #1203567.
Adaptive hash indexing partitioning code has been simplified, potentially improving performance. Bug fixed #1218321.