mysql - mysql.user 表中的 max_connections 列有什么用？

Question

我们都知道:

ma​​x_connections是指所有客户端同时在mysql实例上可以创建的连接总数。

而ma​​x_user_connections是指用户可以同时创建的连接总数。

那么为什么在 mysql.user 表中有一个名为 max_connections 的单独列用于所有用户？因为 ma​​x_connections 对所有用户都是相同的，并且是所有连接的全局变量？

Answer 1

来自MySQL Reference Manual :

MySQL permits limits for individual accounts on use of these server resources:

• The number of queries an account can issue per hour
• The number of updates an account can issue per hour
• The number of times an account can connect to the server per hour
• The number of simultaneous connections to the server by an account

...The server stores resource limits for an account in the user table row corresponding to the account. The max_questions, max_updates, and max_connections columns store the per-hour limits, and the max_user_connections column stores the MAX_USER_CONNECTIONS limit.