In fact, I'll go further: it's basically impossible for our system (and I think it's not an uncommon system for certain types of enterprise software). Part of t

In fact, I'll go further: it's basically impossible for our system (and I think it's not an uncommon system for certain types of enterprise software). Part of the structure of the application is that there's a hierarchy representing our customers and their customers or business units. So company A has "sub-companies" (literal sub-companies, business units or customers) B through Z. A query that runs at the sub-company is perfectly acceptable, but excessively expensive at the higher level. Except for the simplest cases, the application has no clue which queries will be problematic. Who knows that information? Only the database.