If you have a database where querying against v$ Performance views is painful, consider gathering Fixed Object Stats.
Fixed objects are the 700+ X$ tables that feed a lot of these system and performance views.
Fixed Object Stats are _not_ gathered by the default stats gathering procedures. They are not gathered at all unless you run the proc to gather them. In this case Oracle relies heavily on Dynamic Sampling… but that isn’t really a substitute for really gathering stats.
