[obl]

I have no idea about either ruby or rails but since ruby is a managed language this kind of issues seem like they should be pretty easy to debug ?

After all, if the gc is not freeing the memory then it must know a reachable path to it so the blame should be easy to assign.

Does ruby not have any good heap profiling tool ?

[skrebbel]

I don't know anything about Rails but most memory leaks in managed languages are stuff like lists growing infinitely large, parts of them pointing to data that is no longer relevant. Think badly implemented caches, stuff like that.

If you have enough not-perfectly-cleanly-separated layers of data management interacting, then this gets hard to debug pretty fast.

[pjmlp]

Not when you have GC graphical debuggers like Java,.NET and JavaScript do.