Perjury is very common, especially in family court, less so in criminal court, and less so as we move to less and less serious crimes. However, the law distinguishes between false testimony, obstruction and perjury. And in general, these matters are resolved in the court room, because such things are fairly obvious to all concerned. The reason being that incentives are fairly obvious things. And people tend to judge on incentives not testimony.
For example, of the tens of thousands of cases each year, it is pretty uncommon (I don’t have any data right now to refer to) for it to go farther than low double digits.