You're right - the QEWD architecture is as you describe, and not that unusual, though I'm not aware of anyone else having implemented such a design with Node.js. I'm not sure there was a good reason for Node's not using something similar, but then again, I'm not really proposing that Node.js should be like QEWD. The fact is I've been able to implement QEWD's architecture using standard Node.js capabilities. So it provides a way of working around the deficiencies of Node that are a direct result of its intentional architecture, if that's what you want to be able to do - best of both worlds.
Correction: this is actually an emulation of Amazon Web Services' SimpleDB database. It includes an implementation of the SimpleDB SQL-like query language - it's not a full-blown SQL interpreter.
My name has been mentioned a couple of times, so let me give my take.
Forget the Mumps language which always ends up being criticised for all manner of reasons, as witnessed here already.
Check out the database, however - it's the hidden treasure, which sadly gets overlooked and dismissed because of conflation with the Mumps language and its poisonous baggage.
You don't need the Mumps language to access the database. My work with it these days is in JavaScript/Node.js, using it purely as a multi-model NoSQL database, accessed in-process.
Not sure I understand your GC questions, sorry?