XtraDB 是一个MySQL 的存储引擎，其设计的主要目的是用以替代现在的 InnoDB 。XtraDB 100%的兼容 InnoDB 。
- Move to MySQL 5.1.31
- Scalability fix — ability to use several rollback segments
- Scalability fix — replaced page_hash mutex to page_hash read-write lock. See benchmark results.
- Fix broken group commit in InnoDB
- New parameters in the XtraDB io patches:
- innodb_ibuf_max_size — Restrict innodb-insert-buffer size
- innodb_ibuf_active_contract — Enabling it makes the each user threads positive to contract the insert buffer as possible in asynchronous
- innodb_ibuf_accel_rate — This parameter is additional tuning the amount of insert buffer processing by background thread.
- innodb_flush_neighbor_pages — When you use the storage which don’t have “head seek latency” (e.g. SSD or enough Write-Buffered), 0 may show better performance.
- Changed parameter for control read ahead activity. Now it accepts string values:
- innodb_read_ahead = [none|random|linear|both]
- Deb builds for Ubuntu
As you know, the group commit of InnoDB doesn’t work after MySQL 5.0 with binlog.
We pretend to fix this and added “innodb_enable_unsafe_group_commit=[0|1]” parameter. Note if you set this parameter to “1″ record order of binlog and InnoDB transaction log could be not same. But because InnoDB manages transactions in correct order most users may not have problem with this.