Testing mysql2 wait_timeout param

mysql2_wait_timeout.rb

require 'rubygems'
gem 'mysql2'
gem 'activerecord', '3.1.1'
require 'active_record'

# http://dev.mysql.com/doc/refman/5.0/en/server-system-variables.html#sysvar_wait_timeout
MYSQL_WAIT_TIMEOUT_MAX = 2147483

# Testing the remote db connection after a 60s sleep
def test_connection(extra_conf = {})
  conf = {
    :host => "1.2.3.4",
    :username => "root",
    :database => "test",
    :adapter  => "mysql2"
  }
  ActiveRecord::Base.establish_connection(conf.merge(extra_conf))
  puts ActiveRecord::Base.connection.execute("SHOW VARIABLES LIKE \"wait_timeout\"").to_a.join(" : ")
  sleep 60
  puts ActiveRecord::Base.connection.active? ? "Connection up !" : "Connection lost !"
end

test_connection(:wait_timeout => MYSQL_WAIT_TIMEOUT_MAX)
test_connection(:wait_timeout => MYSQL_WAIT_TIMEOUT_MAX + 1)

output

$ ruby mysql2_wait_timeout.rb
wait_timeout : 2147483
Connection up !
wait_timeout : 2147484
Connection lost !

No particular link.just install MySQL 5.6 which has been released a while ago.
In production systems I will stick with 5.1

Please mind that the actual limit for wait_timeout depends on the operating system you are using. The individual values can be retrieved from the MySQL documentation (links v.5.6).

Another point is that I cannot find wait_timeout in Rails 3.2.14 while there are configuration options in Rails 4. I wonder if I am actually able to pass the setting via database.yml.