Clean up CodeIgniter's database (ActiveRecord) memory usage

As what I have found when I was researching there are 2 ways:

• Prevent ActiveRecord from saving query

by

$this->db->save_queries = false;

credit: how can I free the memory used by $this->db->insert()

• Free result memory - CodeIgniter will only reclaim memory when http query processing was returned. If you request is long, you have to free by yourself

by

$query = $this->db->query('SELECT title FROM my_table');
$query->free_result();

credit: last section of Generating Query Results

How to install PHPUnit to Mac OSX

- Install PEAR

curl -O http://pear.php.net/go-pear.phar
php -d detect_unicode=0 go-pear.phar

- Install PHPUnit

sudo pear channel-discover pear.phpunit.de
sudo pear channel-discover pear.symfony-project.com
sudo pear channel-discover components.ez.no
sudo pear install --force --alldeps phpunit/PHPUnit

- Set phpunit bin path to System Environment Variables

Credit
Getting and installing the PEAR package manager
PHPUnit Installed on Mac OSX