发布于 2015-09-25 09:29:37 | 166 次阅读 | 评论: 0 | 来源: 网友投递
Percona XtraDB Cluster 同步多主机复制插件
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 XtraDB Cluster 5..6.25-25.12 发布，二进制包已经提供下载，也已经提供在软件库。
此版本基于 Percona Server 5.6.25-73.1，是个稳定版本。
新特性：
支持 PROXY 协议
Variable wsrep_dirty_reads now has Global scope as well.
MTR coverage has been added to all tests in the Galera suite. Many bugs associated with mtr tests have been fixed.
A new variable gcache.keep_pages_count, analogous to gcache.keep_pages_size, has been added. The variable limits the number of overflow pages rather than the total memory occupied by all overflow pages. Whenever either of the variables are updated at runtime to a non-zero value, cleanup is called on excess overflow pages to delete them. This feature also fixes the bugs with integer overflow in the gcache module.
Updates have been made to wsrep code to ensure greater concordance with binary log and GTID so that failover of async slaves, among nodes of the cluster is seamless and consistent. To ensure this in #1421360, all FLUSH commands (except FLUSH BINARY LOG and FLUSH LOGS, and read lock-based flush such as FLUSH TABLES WITH READ LOCK and FLUSH TABLES FOR EXPORT), ANALYZE TABLE, Percona Server-specific flush statements for user statistics and page tracking bitmaps are executed under Total Order Isolation (TOI) so that they are replicated to other nodes in the cluster when they are written to binary log.
Percona XtraDB Cluster has temporarily disabled savepoints in triggers and stored functions. The reason is that even having fixed bug #1438990 and bug #1464468 we have found more cases where savepoints in triggers break binary logging and replication, resulting in server crashes and broken slaves. This feature will be disabled until the above issues are properly resolved.
Bugs 修复：
SHOW STATUS LIKE ... and SHOW STATUS were taking time proportional to size of gcache.size. Bug fixed #1462674.
When disk space would get filled with gcache.page files, Galera would crash when the next page file was created. Bug fixed #1488535.
XtraBackup SST didn’t clobber backup-my.cnf which caused SST to fail. Bug fixed #1431101.
Error from process::wait was not checked in joiner thread leading to joiner starting erroneously even when SST had failed. Bug fixed #1402166.
Due to an regression introduced in Percona XtraDB Cluster5.6.24-25.11, update of the wsrep_cluster_address variable, following the update of wsrep_provider_options variable would cause the server to deadlock.
mysqldump SST could stall due to a regression in desync mutex introduced in Percona XtraDB Cluster 5.6.24-25.11 by fixing the bug #1288528.
mysql_tzinfo_to_sql sets wsrep_replicate_myisam variable at session scope so that statements are replicated correctly.
Percona-XtraDB-Cluster-devel-56 package was not included in the Percona-XtraDB-Cluster-full-56 metapackage on CentOS due to a conflict with upstream MySQL package.
Running service mysql start and then service mysql@boostrap start afterwards would cause server shutdown.
NO_WRITE_TO_BINLOG / LOCAL for ANALYZE TABLE, OPTIMIZE TABLE, REPAIR TABLE, FLUSH commands will ensure it is not written to binary log (as in mysql async replication) and not replicated in wsrep.
FLUSH TABLES WITH READ LOCK failure (with non-existent tables) didn’t resume the Galera provider, causing deadlock.
Percona XtraDB Cluster will not blocking DDL statements on tables which are used with ... FOR EXPORT or ... WITH READ LOCK, it will give return an error message about read lock.
Fixed the update of wsrep_slave_threads variable regarding the default value assignment, invalid value truncation, and error issued while threads are still being closed.
The mysql client in Percona XtraDB Cluster has been built with system readline instead of editline.
Bugs in 32-bit Galera associated with statvfs in available_storage and integer overflow after multiplication in offset calculation have been fixed.
Galera 3 was failing to build on all non-intel platforms. Architecture specific CCFLAGS have been removed and provision for inheriting CCFLAGS, CFLAGS, CXXFLAGS and LDFLAGS have been added to SConstruct.
Non-global read locks such as FLUSH TABLES WITH READ LOCK and FLUSH TABLES FOR EXPORT paused Galera provider but didn’t block commit globally which wsrep_to_isolation_begin (for DDL) was made aware of.
其他 bug 修复：Percona Server 5.6.26-74.0: bug #1454441, bug #1470677, bug #1472256, bug #1472251, and bug #1464468。
更多内容请看发行说明。
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。
Percona XtraDB Cluster提供了：
同步复制，事务可以在所有节点上提交。
多主机复制，你可以写到任何节点。
从（slave）服务器上的并行应用事件，真正的“并行复制”。
自动节点配置。
数据一致性，不再有未同步的从服务器。
Percona XtraDB Cluster完全兼容MySQL或Percona Server，包括：
数据兼容。Percona XtraDB Cluster可在由MySQL或Percona Server创建的数据库上使用。
应用程序兼容。如果要使用Percona XtraDB Cluster，你的应用程序基本不需要作任何更改。