Years ago, I worked at a large stock trading website. We deliberately used both Oracle SQL and Sybase SQL, with an interface layer. We deliberately did not use

Years ago, I worked at a large stock trading website. We deliberately used both Oracle SQL and Sybase SQL, with an interface layer. We deliberately did not use any special features from either. We ran both in production, some services on one, rest on other. We would occasionally test all services on each one. Reasons: price protection; the product or the vendor would disappear; future upgrades would break our system; sticking with 'standard' SQL features (no shiny new undebugged functions); and easier developer training. What do you do when your sole vendor doubles or triples the price?