The posts_join_paged filter allows you to add join(s) to the posts query in paginated contexts.
It is evaluated in the WP_Query::get_posts() method in the wp-includes/query.php file.
Example:
This filter needs an example! Have an idea? Submit some code.
Have a suggested improvement? You can fork the Gist and comment back with the link. If all is agreeable, I’ll merge in your changes. Crowd-sourced documentation FTW!