MYSQL CLIENT:

create database rbtest;
create user 'rbtest'@'%' identified by 'pdpmetgaic';
grant all on rbtest.* to 'rbtest'@'%';
flush privileges;
use rbtest;

CREATE TABLE `prot` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `sound` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,
  `name` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=6 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

LOCK TABLES `prot` WRITE;
INSERT INTO `prot` VALUES (1,'prrrrrrrr','renza'),(2,'pfffff','loffa'),(3,'prot!','peto'),(4,'BBRAAAMMPP','tuono'),(5,'pruttt','scureggia');
UNLOCK TABLES;




-----
airbot.rb
-----


#!/usr/bin/ruby

puts 'loading libraries...'

require 'rubygems'
require 'active_record'

class MyDB < ::ActiveRecord::Base


  DB_TYPE = 'mysql2'
  DB_HOST = 'MYHOSTNAMEHERE <----'
  DB_USERNAME = 'rbtest'
  DB_PASSWORD = 'pdpmetgaic'
  DB_SCHEMA = 'rbtest'


  establish_connection(:adapter => DB_TYPE, :host => DB_HOST, :username => DB_USERNAME, :password => DB_PASSWORD, :database => DB_SCHEMA, :reconnect => true, :pool => 5, :wait_timeout => 5)
  set_table_name 'prot'


end


puts 'starting!'


i = 0
loop do
  i += 1
  Thread.new do
    begin
      t = i
      s = Time.now
      a = MyDB.find((rand * 5).to_i + 1)
      puts t.to_s + ': ' + a.sound + ' [' + ( "%.2f" % (Time.now - s) ) + 's]'
    rescue Exception => exc
      puts "KABOOM! (#{exc.inspect})"
    end
  end
  sleep 1
end





-----
Output:
-----

loading libraries...
starting!
1: prot! [0.16s]
2: prrrrrrrr [0.00s]
3: BBRAAAMMPP [0.00s]
4: pruttt [0.00s]
5: pfffff [0.00s]
KABOOM! (#<ActiveRecord::ConnectionTimeoutError: could not obtain a database connection within 5 seconds.  The max pool size is currently 5; consider increasing it.>)
9: BBRAAAMMPP [2.01s]
11: prot! [0.01s]
7: prrrrrrrr [4.02s]
6: prrrrrrrr [5.02s]
8: prot! [3.02s]
14: BBRAAAMMPP [3.01s]
12: pfffff [5.01s]