Need Clarification on MemoryStats and Peak Memory Usage

[DHPO]

Hello,

I noticed that the peakXXXMemoryReservation in the MemoryStats structure is defined as the maximum value across all drivers:

struct MemoryStats {
  // ...
  void add(const MemoryStats& other) {
    // ...
    peakUserMemoryReservation =
        std::max(peakUserMemoryReservation, other.peakUserMemoryReservation);
    peakSystemMemoryReservation = std::max(
        peakSystemMemoryReservation, other.peakSystemMemoryReservation);
    peakTotalMemoryReservation =
        std::max(peakTotalMemoryReservation, other.peakTotalMemoryReservation);
    // ...
  }
  // ...
}

In my use case, I'm trying to identify which operator consumes the most memory. It would be more insightful for me to get the sum of the peak memory across all drivers, rather than the maximum.

Considering this, I have a couple of questions:

1. Under what circumstances would it be more beneficial to use the maximum peak memory across all drivers?
2. If my goal is to determine which operator consumes the most memory throughout the entirety of the query, are there other metrics I should consider?

I appreciate any insights or guidance you can provide. Thank you for your time.