Question

I’ve heard that running recursive code on a server can impact performance. How true is this statement, and should recursive method be used as a last resort?

Answer 1

Recursion can potentially consume more memory than an equivalent iterative solution, because the latter can be optimized to take up only the memory it strictly needs, but recursion saves all local variables on the stack, thus taking up a bit more than strictly needed. This is only a problem in a memory-limited environment (which is not a rare situation) and for potentially very deep recursion (a few dozen recursive legs taking up a few hundred bytes each at most will not measurably impact the memory footprint of the server), so “last resort” is an overbid.

But when profiling shows you that the footprint impact is large, one optimization-refactoring you can definitely perform is recursion removal — a popular topic since a few decades ago in the academic literature, but typically not hard to do by hand (especially if you keep all your methods, recursive or otherwise, reasonably small, as you should;-).