为什么MySQL默认事务断绝级别是RR(7)

Cannot execute statement: impossible to write to binary log since BINLOG_FORMAT = STATEMENT and at least one table uses a storage engine limited to row-based logging. InnoDB is limited to row-logging when transaction isolation level is READ COMMITTED or READ UNCOMMITTED.

因此纯真按照步调讲授

步调   SESSION  A   SESSION B  
1  

mysql>set autocommit=0;