The nodata() function retrieves last value from value cache and checks if its timestamp is inside the nodata period. This can result in retrieving value a way beyond the specified range (for example if server was not running for few days).

To optimize nodata() evaluation zbx_vc_get_value_range() function must support both - time period and value count parameters at the same time. This will allow nodata() function to request one value from the specified period and return 0 or 1 depending on if a value was returned or not.