Followup answer re: http://wordpress.stackexchange.com/questions/41667/most-efficient-way-to-search-for-values-from-cpt-in-post-content

indexing_with_cron.php

<?php

add_action('publish_post', 'schedule_glossary_index', 10, 1);
function schedule_glossary_index($post_id) {
	wp_schedule_single_event(time(), 'update_glossary_index', array( $post_id ));
}

add_action('update_glossary_index', 'do_update_glossary_index', 10, 1);
function do_update_glossary_index($post_id) {
	global $wpdb;
	$post_content = $wpdb->get_var("SELECT `post_content` FROM `{$wpdb->posts}` WHERE `ID`=$post_id");
	$wpdb->query("DELETE FROM `{$wpdb->prefix}posts_glossary` WHERE `post_id`=$post_id");
	$sql_regex = rtrim(preg_replace('/[\W\s]*(\w+)[\W\s]*/','$1|',$post_content),'|');
	$wpdb->query(
		"INSERT INTO `{$wpdb->prefix}posts_glossary` (`post_id`,`glossary_id`)
		SELECT $post_id,`ID` FROM `{$wpdb->posts}` WHERE `post_status`='publish' AND `post_type`='glossary' AND `post_parent`>0 AND `post_title` REGEXP('^$sql_regex\$')"
	);
}

?>