[diogenes4]

Many types of memory leaks are simply because you're holding on to data you don't need to hold onto anymore. Languages cannot prevent this, at least not that I've seen.

[byroot]

Sure, but the person I responded to was suggesting that Rails was deliberately holding onto memory to re-use it.

That's absolutely not something Rails does, but it is something that some managed languages and some (most?) allocators do.