Database caching confusion

[eluser]Otemu[/eluser]
$this->db->cache_on();
Manually enables caching.
http://ellislab.com/codeigniter/user-gui...ching.html

$this->db->start_cache()
This function must be called to begin caching. All Active Record queries of the correct type (see below for supported queries) are stored for later use.
http://ellislab.com/codeigniter/user-gui...ecord.html