Count how many users there are

[eluser]Glen Swinfield[/eluser]
In terms of processing time? It's negligible unless you are using it thousands of times. Basically a CI num_rows() function calls mysql_num_rows() eventually I would think - or could in fact call count($query->result_array()) anyway. I've never really looked through the DB files to see exactly what goes on, but generally the fewer function calls the quicker it is.

But don't get too hung up on it because it will be the database itself that slows your apps down, not a few extra function calls.