Store WordPress query in a transient

gistfile1.php

// Let's create the function to be used as a shortcode
function featured_coaches($atts) {

    // My content type is for Motor Coaches, and we want to get the ones that have
    // the Featured box checked, but not the Sold box.

    // I'm starting out saying we want 3, and no sold
    extract(shortcode_atts(array(
        'num' => 3
        ,'sold' => false
    ), $atts));

    // instantiate my output variable
    $output = '';

    // create the transient name
    $transient_name = 'featured_coaches';

    // try getting the transient.
    $featured_coaches = get_transient( $transient_name );

    // if the get works properly, I should have an object in $featured_coaches.
    // If not, run the query.
    if(!is_object($featured_coaches)) {


	// My actual query is kind of irrelevant to this tutorial, but I'm getting 
	// published coaches, no_found_rows is on, ordering by date, and getting the 
	// number indicated in the $num var
        $args = array(
            'post_status' => 'publish'
            ,'post_type' => 'coaches'
            ,'orderby' => 'date'
            ,'posts_per_page' => $num
            ,'no_found_rows' => true
        );

	// here's where I'm setting up the Sold option
        if($sold == false) {
            $args['meta_key'] = 'ecpt_sold';
            $args['meta_value'] = 'on';
            $args['meta_compare'] = 'NOT EXISTS';
        } else {
            $args['meta_key'] = 'ecpt_sold';
            $args['meta_value'] = 'on';
        }

	// here's where I'm taking care of the featured option
        $args['meta_key'] = 'ecpt_featured';
        $args['meta_value'] = 'on';
        $args['meta_compare'] = 'EXISTS';

        // Run the query
        $the_query = new WP_Query( $args );

	// save the results of the query with a 12 hour timeout
        $save_query = set_transient($transient_name,$the_query,60*60*12);

	// load up $featured coaches with the results of the query.  Don't get the
	// transient because it would be the same as the contents of $the_query at
	// this point, and we don't want another database call
        $featured_coaches = $the_query;

    // end object test
    }

    // from here on it's a normal WP_Query setup, but we're looking inside 
    // #featured_coaches for our stuff

    // The Loop
    while ( $featured_coaches->have_posts() ) : $featured_coaches->the_post();
        $output .= get_template_part('loop', 'coach');
    endwhile;

    /* Restore original Post Data
    * NB: Because we are using new WP_Query we aren't stomping on the
    * original $wp_query and it does not need to be reset.
    */
    wp_reset_postdata();

    return $output;

// end recent_coaches
}
add_shortcode('featured_coaches','featured_coaches');