New in Mysql 5.5

這幾點看上去還是蠻有誘惑力的：

1、Improved scalability on multi-core CPUs

2、InnoDBI/O subsystem changes enable more effective use of available I/O capacity.

3、The default storage engine for new tables is InnoDB rather than MyISAM.

4、Support for an interface for semisynchronous replication: A commit performed on the master side blocks before returning to the session that performed the transaction until at least one slave acknowledges that it has received and logged the events for the transaction.

The slave acknowledges receipt of a transaction's events only after the events have been written to its relay log and flushed to disk.

INNODB相關

1、Native Asynchronous I/O for Linux

2、Multiple Buffer Pool Instances

3、Multiple Rollback Segments

4、InnoDB 1.1 revolve around better isolation of threads and mutex contention.

Improved Log Sys Mutex Separate Flush List Mutex（not use with buffer pool as before)

5、 InnoDB Stats in Performance Schema

The has been part of MySQL 5.5 for a while now. InnoDB 1.1 is instrumented for the first time for Performance Schema monitoring, with statistics available for InnoDB-specific mutexes, rw-locks, threads, and I/O operations. The data is structured so that you can see everything, or filter to see just the InnoDB items.

詳見http://dev.mysql.com/doc/refman/5.5/en/mysql-nutshell.html

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