gistfile1.rb

# http://groups.google.com/group/rubyonrails-talk/browse_thread/thread/b29b9ac9b43a5281

seconds_to_wait_for_lock = 5
begin
  raise "Timed out while trying to acquire lock" unless connection.select_value("SELECT GET_LOCK('order_lock_for_product_#{@product.id}', #{seconds_to_wait_for_lock})") == "1"
  # ... validate order availability ...
  # ... create orders ...
rescue
  # ... oh oh ...
  # ... a stuck lock? ...
  # ... somebody do something! ...
ensure
  connection.select_value("SELECT RELEASE_LOCK('order_lock_for_product_#{@product.id}')") 
end