According to Wikipedia, in Landsknecht mercenary armies, there were special front-line troops called Doppelsöldner (Who recieved double pay). These guys were the ones who fought in the frontline, however some were armed with really large swords instead of a pike, and being proficient with one of these immediately qualified you for Doppelsöldner status. These Zweihänder swords were supposedly used on the front lines of pike formations for the explicit purpose of breaking up 'push of pike' engagements, i.e. two pikeman armies going directly against eachother.

However, the same wikipedia article states that whether or not the use of zweihänder swords to break up enemy pike formations was actually effective is disputed.

Wikipedia being Wikipedia, I didn't really know what to think. As such I figured I would ask here: How much do we know of the use of two-handed swords in pike formations and how effective it was at resolving push of pike-stalemates? Surely the Landsknechts wouldn't have used those kinds of soldiers (And spent so much money on actually getting soldiers to take the job) if the two-handed sword tactic was mostly ineffective?