Count and association eager loading

Is there an effective way to get count of records while eager loading associations? Post.includes({:comments => :author}).count produces SELECT COUNT(DISTINCT id) ... LEFT OUTER JOIN ... which is far from optimal. Maybe some pagination plugin does it in a clever way?

EDT 开发者_如何学运维Kaminari gem is able to do it properly, although only for named scopes.

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Have you tried count_by_sql?