do_msql does not block wholly

domysql_block.rb

require 'rubygems'
require 'do_mysql'

# thanks to jeremyevans, he says:
# do_* drivers are async - uses rb_thread_select c-api call to manage
# threads.

# check if this code has been pushed upstream to the mysql library
# also see http://gist.github.com/356250 for plain mysql

thread1 = Thread.new {
  while(true) do 
    print '*'
    sleep 0.1
  end
}

@connection = DataObjects::Connection.new("mysql://root:[email protected]/railsdb")
puts "=== stared blocking"
@reader = @connection.create_command('select sleep(20)').execute_reader
puts "=== created command"
@reader.next!
puts "=== finished blocking"

thread1.join

__END__

OUTPUT:
*=== stared blocking
*******************************************************************************************************************************************************************************************************=== created command
=== finished blocking
****************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************