bbPress FORCE INDEX workaround

bbp-replay-functions.php

function _bbp_has_replies_where( $where, $query ) {

	// Bail if no post_parent to replace
	if ( ! is_numeric( $query->get( 'post_parent' ) ) )
		return $where;

	// Bail if not a topic and reply query
	if ( array( bbp_get_topic_post_type(), bbp_get_reply_post_type() ) != $query->get( 'post_type' ) )
		return $where;

	// Bail if meta query
	if ( $query->get( 'meta_key' ) || $query->get( 'meta_query' ) )
		return $where;

	global $wpdb;

	// Table name for posts
	$table_name = $wpdb->prefix . 'posts';

	// Get the topic ID
	$topic_id   = bbp_get_topic_id();

	// The text we're searching for
	$search     = "WHERE 1=1  AND {$table_name}.post_parent = {$topic_id}";

	$index_suff = stripos($where, 'JOIN') === false ? '' : ' FOR JOIN';

	// The text to replace it with
	$replace    = "FORCE INDEX{$index_suff} (PRIMARY, post_parent) WHERE 1=1 AND ({$table_name}.ID = {$topic_id} OR {$table_name}.post_parent = {$topic_id})";

	// Try to replace the search text with the replacement
	if ( $new_where = str_replace( $search, $replace, $where ) )
		$where = $new_where;

	return $where;
}