wp_cache_example.php

<?php

global $wpdb;

$results = get_transient( 'laurens_random_posts' );
if ( false === $results ) {
 	$results = $wpdb->get_results( "SELECT * FROM {$wpdb->posts} ORDER BY RAND()" );
 	set_transient( 'laurens_random_posts', $results, WEEK_IN_SECONDS );
}

foreach ( $results as $result ) {
	// do stuff
	
}