The Juttle query language allows the expression of dataflow graphs and UDFs which can not (in general) be done natively in ES. As far as the scaling issue goes

The Juttle query language allows the expression of dataflow graphs and UDFs which can not (in general) be done natively in ES. As far as the scaling issue goes, this was designed to run on premise rather than as a SaaS service (unlike bigpanda?). Disclaimer on last paragraph: as per @demmer's comment below, Jut's plans have changed, so it may no longer be valid or relevant.