| GC root |
Starting point for reachability (global, stack, handles) |
| Reachability |
Object is alive if a path exists from any root |
| Retention |
Keeping an object alive via references |
| Shallow size |
Memory owned by the object itself |
| Retained size |
Memory freed if this object were removed |
| Retainer |
Object/primitive holding a reference to another |
| Dominator |
Object through which others are retained |
| Detached DOM |
Node not in document but referenced from JS |
| Closure |
Function capturing outer lexical variables |
| Major GC |
Full/old-generation collection |
| Minor GC |
Young-generation (scavenge) collection |
| RSS |
Resident Set Size — process RAM usage |
| heapUsed |
V8 JavaScript object heap in use |
| external |
Memory for native bindings (Buffers) |
| Sawtooth |
Healthy heap graph — up then down with GC |
| Staircase |
Leak graph — troughs rise over time |
| OOM |
Out of memory — process crash or kill |
| Soak test |
Long-running steady load to expose slow leaks |
| LRU |
Least Recently Used cache eviction |