New Features
Percona XtraDB Cluster is now based on wsrep API 25 and Galera 25.2.x.
Limited support for Query Cache has been implemented. Query cache cannot still be fully enabled during the startup. To enable query cache, mysqld should be started with query_cache_type=1 and query_cache_size=0 and then query_cache_size should be changed to desired value during runtime.
RPM packages are now made relocatable which means they now support installation to custom prefixes.
XtraBackup SST now supports innodb_data_home_dir and innodb_log_home_dir in the configuration file.
The binaries are now statically linked with regard to Galera library which depended on OpenSSL library.
Bugs fixed
Product suffix has been added to the Percona XtraDB Cluster rpm packages, which means that packages have been renamed from Percona-XtraDB-Cluster-server to Percona-XtraDB-Cluster-server-55. Bug fixed #1255616.
Fixed the dependency issue which caused Percona XtraDB Cluster 5.5 installation to fail on Ubuntu 12.04. Bug fixed #1247861.
When installing first Percona-XtraDB-Cluster-client and then Percona-XtraDB-Cluster-server on two single statements or a single statement with both packages , yum would install percona-xtrabackup-20 instead percona-xtrabackup package as dependency of Percona-XtraDB-Cluster-server. Bug fixed #1226185.
If SELECT FOR UPDATE... query was aborted due to multi-master conflict, the client wouldn’t get back the deadlock error. From client perspective the transaction would be successful. Bug fixed #1187739.
Temporary tables are not replicated, but any DDL on those tables were (in this case it was TRUNCATE), which would generates error messages on other nodes. Bug fixed #1194156.
When setting the gcache.size to a larger value than the default 128M, the mysql service command did not allow enough time for the file to be preallocated. Bug fixed #1207500.
CREATE TABLE AS SELECT would fail with explicit temporary tables, when binlogging was enabled and autocommit was set to 0. Bug fixed #1240098.
Write set flags defined in wsrep API are now exposed to application side appliers too. Bug fixed #1247402.
Local brute force aborts are counted accurately. Bug fixed #1247971.
Certain combinations of transaction rollbacks could leave stale transactional MDL locks and cause deadlocks. Bug fixed #1247978.
After turning UNIV_SYNC_DEBUG on, node that was started from clean state would crash immediately at startup. Bug fixed #1248908.
Server built with UNIV_SYNC_DEBUG would assert if SQL load has DELETE statements on tables with foreign key constraints with ON DELETE CASCADE option. Bug fixed #1248921.
Xtrabackup SST dependencies have been added as Suggested dependencies for DEB packages. Bug fixed #1250326.
init stop script on CentOS didn’t wait for the server to be fully stopped. This would cause unsuccessful server restart because the start action would fail because the daemon would still be running. Bug fixed #1254153.
Memory leak in mem_root has been fixed. Bug fixed #1249753.
Galera is now packaged with garbd init script. Bug fixed #1256769.
