如何增加Ubuntu服务器上MySQL的max_connections值？
问题描述：
我在Ubuntu服务器14.04上使用MySQL 5.6，并且想要增加允许的最大同时连接数（当前设置为默认值151）。如何增加Ubuntu服务器上MySQL的max_connections值？
负责此操作的是/etc/mysql/my.cnf中的设置max_connections。所以我将它设置为200并重新启动MySQL服务器。现在，它的值是200：
$ cat /etc/mysql/my.cnf | grep "connections"
max_connections = 200
$ /etc/init.d/mysql restart
* Stopping MySQL database server mysqld [ OK ]
* Starting MySQL database server mysqld [ OK ]
* Checking for tables which need an upgrade, are corrupt or were
not closed cleanly.
但一切都没有改变：
SHOW VARIABLES LIKE "max_connections";
+-----------------+-------+
¦ Variable_name ¦ Value ¦
+-----------------+-------+
¦ max_connections ¦ 151 ¦
+-----------------+-------+
如何获得的max_connections工作自定义配置？
$ ulimit -a | grep "open"
open files (-n) 1024
$ ulimit -n 4096
$ ulimit -a | grep "open"
open files (-n) 4096
添加到/etc/security/limits.conf：
* soft nofile 1024000
* hard nofile 1024000
* soft nproc 10240
* hard nproc 10240
root soft nproc unlimited
添加到/etc/mysql/my.cnf：
[mysqld_safe]
open_files_limit = 1024000
[mysqld]
open_files_limit = 1024000
但它似乎被忽略：
SHOW STATUS LIKE 'open%';
+--------------------------+-------+
¦ Variable_name ¦ Value ¦
+--------------------------+-------+
¦ Open_files ¦ 52 ¦
+--------------------------+-------+
¦ Open_streams ¦ 0 ¦
+--------------------------+-------+
¦ Open_table_definitions ¦ 434 ¦
+--------------------------+-------+
¦ Open_tables ¦ 417 ¦
+--------------------------+-------+
¦ Opened_files ¦ 847 ¦
+--------------------------+-------+
¦ Opened_table_definitions ¦ 0 ¦
+--------------------------+-------+
¦ Opened_tables ¦ 0 ¦
+--------------------------+-------+
为了避免错误的文件设置正确的configs的情况下，我在所有这些文件中设置的选项（有些人是不存在的，所以我创造了他们）：
$ mysqld --help --verbose | grep -B 1 cnf
Default options are read from the following files in the given order:
/etc/my.cnf /etc/mysql/my.cnf /usr/etc/my.cnf ~/.my.cnf
无影响。
答
您将不得不增加对您的操作系统的打开文件限制，并且之后可以将更高的max_connections值。
答
[mysqld]
MAX_CONNECTIONS = 400个
MAX_USER_CONNECTIONS = 300
你必须max_connections属性添加为下面的[mysqld]。对我来说它的工作..
刚刚完成（'ulimit -n 4096'）并重新启动MySQL。没有效果。 – automatix