Actually, we tried both exhaustive search and sufficient search (where we had a soft-deadline and accepted the best solution reached within the deadline). Even with this dark launch found queries in our stream that had unacceptable delays. We were in contact with the team through the development process, so we at least had some reason for belief that we were using best practices. And you're right that ultimately the CP solver wasn't the right tool for this job -- simplifying the problem and giving up some capabilities was the solution. We had hoped that a general solution would be feasible, as that would allow expressing some things efficiently which we couldn't in our existing setup. But it was not to be.
