Ruby 2.2.0 在假期前釋出:「Ruby 2.2.0 Released」。
在「Notable Changes since 2.1」的部份有提到新的 GC algorithm (Incremental GC) 以及讓 Symbol 可以被 GC (Symbol GC),而且提到了 Rails 5.0 會受益於此:
Recent developments mentioned on the Rails blog suggest that Rails 5.0 will take advantage of Incremental GC as well as Symbol GC.
在 Rails 這邊的說明:
Rails 5.0 will target Ruby 2.2+ exclusively. There are a bunch of optimizations coming in Ruby 2.2 that are going to be very nice, but most importantly for Rails, symbols are going to be garbage collected.