MySQL:事务隔离级别、死锁
我有一个导入产品的长时间运行过程,有时会出现死锁错误。据我所知,我认为如果在脚本执行期间,我将隔离级别切换为可序列化的,我将解决死锁问题。但是,我能做什么呢?我能打开两个终端,用MySQL:事务隔离级别、死锁,mysql,transactions,isolation-level,database-deadlocks,Mysql,Transactions,Isolation Level,Database Deadlocks,我有一个导入产品的长时间运行过程,有时会出现死锁错误。据我所知,我认为如果在脚本执行期间,我将隔离级别切换为可序列化的,我将解决死锁问题。但是,我能做什么呢?我能打开两个终端,用Serializable重现死锁 conn1: SET GLOBAL TRANSACTION ISOLATION LEVEL SERIALAZIBLE; conn1: START TRANSACTION; conn2: START TRANSACTION; conn1: UPDATE core_config_data s
Serializable
重现死锁
conn1: SET GLOBAL TRANSACTION ISOLATION LEVEL SERIALAZIBLE;
conn1: START TRANSACTION;
conn2: START TRANSACTION;
conn1: UPDATE core_config_data set value = 1 WHERE config_id = 1;
conn2: UPDATE core_config_data set value = 1 WHERE config_id = 2;
conn1: UPDATE core_config_data set value = 1 WHERE config_id = 2; waiting...
conn2: UPDATE core_config_data set value = 1 WHERE config_id = 1; ERROR 1213 (40001): Deadlock found when trying to get lock; try restarting transaction
好的,之后我尝试了脏读
和读未限制
:
conn1: SET GLOBAL TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
conn1: START TRANSACTION;
conn1: SELECT junk FROM employees WHERE employee_id = 1; junk=test;
conn2: START TRANSACTION;
conn2: update employees set junk='test1' where employee_id = 1;
conn1: SELECT junk FROM employees WHERE employee_id = 1; junk=test;
你知道我哪里弄错了吗?一切都如期而至。仅仅通过隔离级别是无法避免死锁的;隔离级别仅用于数据的完整性 通过确保更新行的顺序相同,可以解决许多死锁问题。这样,第一个连接将能够在没有死锁的情况下处理到底,然后连接2也将失败或成功