hollow/src/main/java/com/netflix/hollow/api/metrics/HollowMetrics.java
void calculateTypeMetrics(HollowReadStateEngine hollowReadStateEngine) {
        Collection<HollowTypeReadState> typeStates = hollowReadStateEngine.getTypeStates();
        if (typeStates == null)
            return;

        totalHeapFootprint = 0L;
        totalPopulatedOrdinals = 0;
        for (HollowTypeReadState typeState : typeStates) {
            long heapCost = typeState.getApproximateHeapFootprintInBytes();
            totalHeapFootprint += heapCost;

            int populatedOrdinals = typeState.getPopulatedOrdinals().cardinality();
            totalPopulatedOrdinals += populatedOrdinals;
            String type = typeState.getSchema().getName();
            typeHeapFootprint.put(type, heapCost);
            typePopulatedOrdinals.put(type, populatedOrdinals);
        }
    }
void calculateTypeMetrics(HollowReadStateEngine hollowReadStateEngine) {
        Collection<HollowTypeReadState> typeStates = hollowReadStateEngine.getTypeStates();
        if (typeStates == null)
            return;

        totalHeapFootprint = 0L;
        totalPopulatedOrdinals = 0;
        for (HollowTypeReadState typeState : typeStates) {
            long heapCost = typeState.getApproximateHeapFootprintInBytes();
            totalHeapFootprint += heapCost;

            int populatedOrdinals = typeState.getPopulatedOrdinals().cardinality();
            totalPopulatedOrdinals += populatedOrdinals;
            String type = typeState.getSchema().getName();
            typeHeapFootprint.put(type, heapCost);
            typePopulatedOrdinals.put(type, populatedOrdinals);
        }
    }
Calculates the memory heap footprint and populated ordinals per type and total
@param hollowReadStateEngine