Wordpress "Loop" with large set of results

Question

I'm not sure the appropriate terminology but I have a wordpress "loop" for a custom post type that has roughly 300 results that all get displayed on a single page (no paging). The causes an enormous load on the DB server because for every "post" in the "loop" there are like N database calls (the_title, has_post_thumbnail, get_post_thumbnail_id, the_content, get_post_meta, etc..). What is the wordpress way of optimizing this? For something like this do most developers just drop to doing queries with $wpdb or is the wordpress way to cache the page and move on? I looked at doing straight $wpdb sql queries but grabbing the relevant data (especially images associated with the post) is less then intuitive.

Answer 1

You can use the Transients API to cache the entire HTML output so the queries are not done every time the page is loaded:

$transient = 'my-300-posts';
$timeout   = 3600; // 1 hour

if ( false === $out = get_transient( $transient ) ) {

    $args = array( YOUR ARGS GO HERE );
    $posts = get_posts( $args );
    if ( $posts ) {
        foreach ( $posts as $post ) {
            $out .= get_the_title( $post->ID );
            $out .= // whatever else you want to output...
        }
    }

    if ( $out ) {
        set_transient( $transient, $out, $timeout );
    }

}

echo $out;

However, you're still serving 300 post thumbnails on one page load, which is a lot of data to transfer.

(You also need to delete the transient on the save_post and delete_post hooks)

Maybe you'd be better off with infinite scrolling? It's an option in the Jetpack plugin.