How to set Max_connections in MySQL without restart?

The Managed WordPress servers allows for 24 concurrent connections. Unfortunately this value is not able to be increased. If you require a service that will need additional connections, you may want to consider a VPS server, as that will allow you to have a higher default value of 100, with the ability to increase the value further if desired.

Overview

If you get a Too many connections error when you try to connect to the mysqld server, this means that all available connections are in use by other clients. The number of connections permitted is controlled by the max_connections system variable. Its default value is 100. If you need to support more connections, you should set a larger value for this variable.

The MySQL SmartPool v.2 for the Grid comes with 30 MySQL connections.

If you get a Too many connections error when you try to connect to the

[mysqld]
local-infile=0
datadir=/var/lib/mysql
user=mysql
symbolic-links=0

max_connections = 100

The number of connections permitted is controlled by the

[mysqld]
local-infile=0
datadir=/var/lib/mysql
user=mysql
symbolic-links=0

max_connections = 100

Requirements

Before you start, this article has the following dependencies:

• You must have SSH access set up for root or a sudo user.
  • How do I enable root access to my DV?
  • How do I disable SSH login for the root user?

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Instructions

It is possible to upgrade your concurrent MySQL connections by adding a MySQL GridContainer to your Grid hosting package. The three different sizes offered are 60, 100, and 150 concurrent connections respectively.

For more information on the MySQL GridContainer, please see our Grid product page.

To increase the maximum connections that MySQL allows, you must edit the file

[mysqld]
local-infile=0
datadir=/var/lib/mysql
user=mysql
symbolic-links=0

max_connections = 100

vi /etc/my.cnf

There will be a section that looks like this: (may be slightly different)

[mysqld]
local-infile=0
datadir=/var/lib/mysql
user=mysql
symbolic-links=0

max_connections = 100

Under [mysqld], you can increase your maximum MySQL connections by changing the max_connections attribute to something like this.

[mysqld]
safe-show-database
innodb_data_file_path=ibdata1:10M:autoextend
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock

Add the following line under [mysqld]

max_connections=250

The resulting config file should resemble this:

[mysqld]
safe-show-database
innodb_data_file_path=ibdata1:10M:autoextend
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
max_connections=250

Save the changes and type the following to restart mysqld:

/etc/init.d/mysqld restart

You will see:

Stopping mysql: [ OK ]
Starting mysql: [ OK ]

If stopping FAILS, then you did something wrong. Try to backtrack and make sure you entered the new setting correctly.

NOTE:

If you'd like to check to see if this setting was successfully applied, you may check using one of the following methods:

If you are getting “too many connections” errors in MySQL you can change the max_connections setting to allow more connections, assuming you have enough RAM to handle the increased number. This post looks at how to update the max_connections setting in MySQL.

The default setting for max_connections is 100. You can see what the current setting is by running the following SQL command from the MySQL command line tool, phpMyAdmin, or a similar tool:

show variables like "max_connections";

This will return a resultset like this, showing you what your current max connections setting is:

+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| max_connections | 100   |
+-----------------+-------+

You can change the setting to e.g. 200 by issuing the following command without having to restart the MySQL server (obviously it will only work if the user you are logged in as has sufficient permissions to do this):

set global max_connections = 200;

This will take effect immediately, but will be forgotten the next time MySQL is restarted. To make the change permanent you need to edit the my.cnf configuration file. On CentOS, RedHat and similar distributions this is at /etc/my.cnf; other distros will store it elsewhere.

Under the [mysqld] section add the following setting:

max_connections = 200

Now when you restart MySQL the next time it will use this setting instead of the default.

Note that increasing the number of connections that can be made will increase the potential amount of RAM required for MySQL to run. Increase the max_connections setting with caution!

How to set Max_connections permanently in MySQL?

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What is the default Max_connections in MySQL?

How to get max connections in MySQL?