三种查询和设置隔离等级的方法

select @@tx_isolation

set tx_isolation = 'XXXXXX'

select @@session.tx_isolation

set @@session.tx_isolation = ‘xxx’ (如果设置了tx 则不需要设置session)

select @@global.tx_isolation

set @@global.tx_isolation = ‘xxx’

ps:四种隔离等级分别为：

read-uncommitted   

read-committed

repeatable-read

serializable