etcdutl Snapshot Status: TotalKey Calculation Inquiry

[jxustc]

Problem Description

When using the etcdutl snapshot status command, I've observed the following characteristics of TotalKey calculation:

• Current implementation counts keys across all buckets in the bbolt database
• Includes keys beyond visible etcd key-value data
• Key counts in other buckets may vary with different etcd versions

Case

During testing, I discovered that the TotalKey calculation includes keys from various internal buckets beyond the main key-value store:

Identified Included Keys

• In meta bucket:
  • term
  • scheduledCompactRev
  • confState
  • ...
• In auth bucket:
  • authRevision
• Keys from other internal buckets

Specific Questions

1. What is the precise definition of TotalKey?
2. Is the current calculation method appropriate?
3. Should the count be limited to etcd key-value entries?

Potential Implementation Approach

func (s *v3Manager) Status(dbPath string) (ds Status, err error) {
	...
	if err = db.View(func(tx *bolt.Tx) error {
		...
		c := tx.Cursor()
		for next, _ := c.First(); next != nil; next, _ = c.Next() {
			b := tx.Bucket(next)
			if b == nil {
				return fmt.Errorf("nil bucket: %q", string(next))
			}
			_, err = h.Write(next)
			if err != nil {
				return fmt.Errorf("cannot hash bucket name: %q err: %w", string(next), err)
			}

			iskeyb := (bytes.Equal(next, schema.Key.Name()))
			if err = b.ForEach(func(k, v []byte) error {
				_, err = h.Write(k)
				if err != nil {
					return fmt.Errorf("cannot hash bucket key: %q err: %w", k, err)
				}
				_, err = h.Write(v)
				if err != nil {
					return fmt.Errorf("cannot hash bucket key: %q value: %q err: %w", k, v, err)
				}
				if iskeyb {
					var rev mvcc.Revision
					rev, err = bytesToRev(k)
					if err != nil {
						return fmt.Errorf("cannot parse revision key: %q err: %w", k, err)
					}
					ds.Revision = rev.Main

					var kv mvccpb.KeyValue
					err = kv.Unmarshal(v)
					if err != nil {
						return fmt.Errorf("cannot unmarshal value, key: %q value: %q err: %w", k, v, err)
					}
                                         // move to here 
                                         ds.TotalKey++
				}
                                 // remove 
				ds.TotalKey++
				return nil
			}); err != nil {
				return fmt.Errorf("error during bucket key iteration, name: %q err: %w", string(next), err)
			}
		}
		return nil
	}); err != nil {
		return ds, err
	}
...
}

Besides this solution, could we possibly add a field to count the number of non-built-in key-value pairs in etcd?

Proposed Improvement

If appropriate, I am willing to submit a PR to implement this change.