- Percona XtraDB Cluster has ported Twitter’s MySQL NUMA patch. This patch implements improved NUMA support as it prevents imbalanced memory allocation across NUMA nodes.
- Number of binlog files can be restricted when using Percona XtraDB Cluster with the new max_binlog_files option.
- New status variable wsrep_incoming_addresses has been introduced. It contains a comma-separated list of incoming (client) addresses in the cluster component.
- Multiple addresses can now be specified in the gcomm:// URLwhen defining the address to connect to cluster. Option wsrep_urls is now deprecated, wsrep_cluster_address should be used to specify multiple addresses instead.
- GTID can now be recovered by starting mysqld with –wsrep-recover option. This will parse GTID from log, and if the GTID is found, assign it as initial position for actual server start.
- SET PASSWORD command replication has been implemented. The SET statement can contain other variables and several password changes, and each password change will be replicated separately as one TOI (total order isolation) call. The user does not have to be explicitly defined, current user will be detected and correct SET PASSWORD statement will be generated for TOI replication in every use case.
- SQL statements aborted due to multi-master conflict can be automatically retried. This can be controlled with wsrep_retry_autocommit variable. The retry will happen only if there is real abort for the SQL statement. If statement itself enters into commit phase and detects certification failure, there will be no retry.
- This version of Percona XtraDB Cluster implements significant speedups and memory footprint reduction on ranged queries.
- Some wsrep variables, like wsrep_provider, wsrep_provider_options and wsrep_cluster_address, could be “doubly” allocated which could cause memory leak. Bug fixed #1072839.
- In case variables wsrep_node_address and wsrep_node_incoming_address were not set explicitly, port number would be set to 0. Bug fixed #1071882.
- Server would hang before storage engine initialization with rsync SST and with option wsrep_start_position enabled. Bug fixed #1075495.
- SST script interface has been upgraded to use named instead of positional parameters. Bug fixed #1045026.
- When server was started with no wsrep_provider and with regular MySQL replication slave configured, could cause intermittent failure to start MySQL slave during startup. Bug fixed #1075617.
- If DDL is processing with RSU method and there is MDL conflict with local transaction, this conflict would remain unresolved. Bug fixed #1039514.
- Static SST method list has been removed. Bug fixed #1045040.
- DDL in multi-statement would cause a server crash. Bug fixed #1049024.
- mysqld_safe doesn’t restart the node automatically anymore. Bug fixed #1077632.
- Server would fail to start if the variable wsrep_provider was unset. Bug fixed #1077652.
Based on Percona Server 5.5.28-29.1 including all the bug fixes in it, Percona XtraDB Cluster 5.5.28-23.7 is now the current stable release. All of Percona‘s software is open-source and free.
We did our best to eliminate bugs and problems, but this is a software, so bugs are expected. If you encounter them, please report them to our bug tracking system.