Percona XtraDB Cluster 5.6.21-25.8 发布了，该版本基于 Percona Server 5.6.21-70.1。 Percona XtraDB Cluster是针对MySQL用户的高可用性和扩展性解决方案，基于Percona Server 。其包括了Write Set REPlication补丁，使用Galera 2.0库，这是一个针对事务性应用程序的同步多主机复制插件。 Percona Server是MySQL的改进版本，使用 XtraDB 存储引擎，在功能和性能上较 MySQL 有着很显著的提升，如提升了在高负载情况下的 InnoDB 的性能，为 DBA 提供了一些非常有用的性能诊断工具，另外有更多的参数和命令来控制服务器行为。 完整的改进记录包括： 新特性: Galera 3.8 introduces auto-eviction for nodes in the cluster experiencing network issues like packet loss. It is off by default and is turned on with evs.auto_evict option. This feature requires EVS protocol version (evs.version) 1. During the EVS protocol upgrade all membership changes are communicated over EVS protocol version 0 to preserve backwards compatibility, protocol is upgraded to the highest commonly supported version when forming a new group so if there exist a single node with older version in the group, the group protocol version remains as 0 and auto-eviction is not functional. (#1274192). Percona XtraDB Cluster now supports backup locks in XtraBackup SST (in the default xtrabackup-v2 wsrep_sst_method). Backup locks are used in lieu of FLUSH TABLES WITH READ LOCK on the donor during SST. This should allow for minimal disruption of existing and incoming queries, even under high load. Thus, this should allow for even faster SST and node being in ‘donor/desynced’ state. This also introduces following constraints: Percona XtraDB Cluster 5.6.21 requires Percona XtraBackup 2.2.5 or higher; An older (< 5.6.21) joiner cannot SST from a newer (>= 5.6.21) donor. This is enforced through SST versioning (sent from joiner to donor during SST) and logged to error log explicitly. (#1390552). Percona XtraDB Cluster is now shipped with Galera MTR test suite. Bugs 修复: Percona XtraDB Cluster now shows a warning in case additional utilities, like pv which may not affect critical path of SST, are not installed. Bug fixed #1248688. mysqldump SST can now use username/password from wsrep_sst_auth under group of [sst] in my.cnf in order not to display the credentials in the error log. Bug fixed #1293798. Normal shutdown under load would cause server to remain hanging because replayer failed to finish. Bug fixed #1358701. wsrep_causal_reads variable was not honored when declared as global. Bug fixed #1361859. garbd would not work when cluster address was specified without the port. Bug fixed #1365193. If mysqld gets killed during the SST it will leave an unclean data directory behind. This would cause Percona XtraDB Cluster to fail when the server would be started next time because the data directory would be corrupted. This was fixed by resuming the startup in case wsrep-recover failed to recover due to corrupted data directory. The old behavior is still achievable through --exit-on-recover-fail command line parameter to mysqld_safe or exit-on-recover-fail under [mysqld_safe] in my.cnf. Bug fixed #1378578. Percona XtraDB Cluster now reads environment variables for mysqld from following files (if present): /etc/default/mysql in Debian/Ubuntu; /etc/sysconfig/mysql in CentOS 6 or lower; /etc/sysconfig/mysql in CentOS 7 with mysql.service; /etc/sysconfig/XYZ in CentOS 7 with mysql@XYZ.service (/etc/sysconfig/bootstrap is supplied by default). Bug fixed #1381492. gvwstate.dat file was removed on joiner when Xtrabackup SST method was used. Bug fixed #1388059. Percona XtraDB Cluster now detects older joiners which don’t have the backup lock support. Bug fixed #1390552. Inserts to a table with auto-increment primary key could result in duplicate key error if another node joined or dropped from the cluster during the insert processing. Bug fixed #1366997. TOI now skips replication if all tables are temporary. Bugs fixed #11 and #13. Bootstrapping a node tried to resolve gcomm address list specified in wsrep-cluster-address. Bug fixed #88. In case stored procedure containing a non-InnoDB statement (MyISAM) performed autocommit, that commit would be entered two times: at statement end and next time at stored procedure end. Bug fixed #2. Two appliers conflicting with local transaction and resulting later in (acceptable) BF-BF lock conflict, would cause cluster to hang when the other BF thread would not grant the lock back after its local transaction got aborted. Bug fixed #7. 其他 Bug 修复 #1378138, #1377226, #1376965, #1356859, #1026181, #1367173, #1390482, #1391634, and #1392369. Percona XtraDB Cluster 5.6.21-25.8 发布下载地址
