Metro_Sitemap::get_last_modified_posts PHP Method

    public static function get_last_modified_posts()
    {
        global $wpdb;
        $sitemap_last_run = get_option('msm_sitemap_update_last_run', false);
        $date = date('Y-m-d H:i:s', current_time('timestamp', 1) - 3600);
        // posts changed within the last hour
        if ($sitemap_last_run) {
            $date = date('Y-m-d H:i:s', $sitemap_last_run);
        }
        $post_types_in = self::get_supported_post_types_in();
        $modified_posts = $wpdb->get_results($wpdb->prepare("SELECT ID, post_date FROM {$wpdb->posts} WHERE post_type IN ( {$post_types_in} ) AND post_modified_gmt >= %s ORDER BY post_date LIMIT 1000", $date));
        return $modified_posts;
    }

 /**
  * Generates sitemaps from the latest posts.
  *
  * Hooked into the msm_sitemap_actions-generate_from_latest action
  */
 public static function action_generate_from_latest()
 {
     $last_modified = Metro_Sitemap::get_last_modified_posts();
     if (count($last_modified) > 0) {
         Metro_Sitemap::update_sitemap_from_modified_posts();
         Metro_Sitemap::show_action_message(__('Updating sitemap from latest articles...', 'metro-sitemaps'));
     } else {
         Metro_Sitemap::show_action_message(__('Cannot generate from latest articles: no posts updated lately.', 'metro-sitemaps'), 'error');
     }
 }