In order to answer this question, one has to understand V8’s Memory Scheme first.
A running program is always represented through some space allocated in memory. This space is called Resident Set. V8 uses a scheme similar to the Java Virtual Machine and divides the memory into segments:
- Code: the actual code being executed
- Stack: contains all value types (primitives like integer or Boolean) with pointers referencing objects on the heap and pointers defining the control flow of the program
- Heap: a memory segment dedicated to storing reference types like objects, strings and closures.
Now it is easy to answer the question:
- rss: Resident Set Size
- heapTotal: Total Size of the Heap
- heapUsed: Heap actually Used
Ref: http://apmblog.dynatrace.com/2015/11/04/understanding-garbage-collection-and-hunting-memory-leaks-in-node-js/