58 my ass

wtf.rb

require 'mysql2'

client = Mysql2::Client.new(:host => "localhost", :username => "root",:database => "test")

100.times do |i|
	str = "insert into money_test ( money) values (#{rand(100)})"
	p str
	client.query(str)
end

def exec()
	money = -1
	client = Mysql2::Client.new(:host => "localhost", :username => "root",:database => "test")
	client.query("select id,money from money_test where id = 89").each do |row|
		p money = row['money']		 
	end
	update_string = "update money_test set money = #{money}  + 1 where id = 89 and money = #{money}"
	client.query(update_string)
end

a = []

5.times { a << Thread.new { exec } }

a.map { |i| i.join }