instance method flush_all

# File activesupport/lib/active_support/vendor/memcache-client-1.5.1/memcache.rb, line 403
  def flush_all
    raise MemCacheError, 'No active servers' unless active?
    raise MemCacheError, "Update of readonly cache" if @readonly
    begin
      @mutex.lock if @multithread
      @servers.each do |server|
        begin
          sock = server.socket
          raise MemCacheError, "No connection to server" if sock.nil?
          sock.write "flush_all\r\n"
          result = sock.gets
          raise_on_error_response! result
          result
        rescue SocketError, SystemCallError, IOError => err
          server.close
          raise MemCacheError, err.message
        end
      end
    ensure
      @mutex.unlock if @multithread
    end
  end