... while setting up huge MySQL installations with a dozen+ replicas ... If you're careful about your function calls, sure. Include a UUID() or SYSDATE() in

... while setting up huge MySQL installations with a dozen+ replicas ... If you're careful about your function calls, sure. Include a UUID() or SYSDATE() in your INSERT statements, and the replication goes to pieces as the function calls are run separately on each slave (with differing results).