Xsn - 57 is an update operation under serializable isolation Xsn - 57是序列化隔离下的更新操作。
The scan is performed with the same semantics as a transaction running at the serializable isolation level 执行扫描时所用的语义与在serializable隔离级别运行的事务的语义相同。
Locking a range of keys allows transactions running at the serializable isolation level to prevent phantom inserts and deletes 锁定某个范围内的键,使事务可以运行在可序列化隔离级别,防止假插入和假删除。
Second , most applications don ' t need serializable isolation ( phantom reads aren ' t usually a problem ) , and this isolation level tends to scale poorly 其次,绝大部分应用都无需使用“序列化”隔离(一般来说,读取幻影数据并不是一个问题) ,此隔离级别也难以测量。
Few existing applications use serializable isolation in production ; rather , they use pessimistic locks , which effectively forces a serialized execution of operations in certain situations 目前使用序列化隔离的应用中,一般都使用的悲观锁,这样强行使得所有事务都序列化执行。