BuddyPress.org

I’ve been having some CPU overloads on my Buddypress site, and have started logging slow sql queries. I’m seeing a lot like this:

SELECT DISTINCT a.*, u.user_email, u.user_nicename, u.user_login, u.display_name  FROM wp_bp_activity a LEFT JOIN wp_users u ON a.user_id = u.ID  WHERE a.is_spam = 0 AND a.hide_site
wide = 0 AND a.type != 'activity_comment' ORDER BY a.date_recorded DESC LIMIT 0, 50;
# Time: 140225 11:39:07

What’s noticable about these queries is that there is no filtering on user or group, which I presume is why they’re taking so long…
I can see that the function building the query is get in bp-activity-classes.php, but I can’t find where these queries are fired from, with no user or group specified.
Any ideas?