问题描述
查询:
SELECT COUNT(online.account_id) cnt from online;
但是在线表也被一个事件修改,所以我经常可以通过运行show processlist
看到锁.
But online table is also modified by an event, so frequently I can see lock by running show processlist
.
MySQL 中有没有什么语法可以让 select 语句不引起锁?
Is there any grammar in MySQL that can make select statement not causing locks?
我忘记在上面提到它在 MySQL 从数据库上.
And I've forgotten to mention above that it's on a MySQL slave database.
在我添加到 my.cnf:transaction-isolation = READ-UNCOMMITTED
之后从站会遇到错误:
After I added into my.cnf:transaction-isolation = READ-UNCOMMITTED
the slave will meet with error:
错误无法进行二进制日志记录.消息:InnoDB 中的事务级别READ-UNCOMMITTED"对于查询时的二进制日志模式STATEMENT"不安全
那么,有没有兼容的方法来做到这一点?
So, is there a compatible way to do this?
推荐答案
找到一篇名为MYSQL WITH NOLOCK"的文章
Found an article titled "MYSQL WITH NOLOCK"
https://web.archive.org/web/20100814144042/http://sqldba.org/articles/22-mysql-with-nolock.aspx
在 MS SQL Server 中,您将执行以下操作:
in MS SQL Server you would do the following:
SELECT * FROM TABLE_NAME WITH (nolock)
和 MYSQL 等价的是
and the MYSQL equivalent is
SET SESSION TRANSACTION ISOLATION LEVEL READ UNCOMMITTED ;
SELECT * FROM TABLE_NAME ;
SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ ;
编辑
Michael Mior 提出以下建议(来自评论)
Michael Mior suggested the following (from the comments)
SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED ;
SELECT * FROM TABLE_NAME ;
COMMIT ;
这篇关于有什么方法可以在不导致 MySQL 锁定的情况下进行选择?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!