WordPress at a glance
filter is not described

posts_search_orderby filter-hook . WP 3.7.0

Filters the ORDER BY used when ordering search results.

Usage

add_filter( 'posts_search_orderby', 'filter_function_name_383', 10, 2 );
function filter_function_name_383( $search_orderby, $this ){
	// filter...

	return $search_orderby;
}
$search_orderby(string)
The ORDER BY clause.
$this(WP_Query)
The current WP_Query instance.

Where the hook is called

WP_Query::get_posts()
wp-includes/class-wp-query.php 2204
$search_orderby = apply_filters( 'posts_search_orderby', $search_orderby, $this );

Where the hook is used (in WP core)

Does not used.