dgraph-io/dgraph · error

StartUid length != 8 for key: %q, parsed key: %+v

Error message

StartUid length != 8 for key: %q, parsed key: %+v

What it means

Error returned by x/keys.go while parsing a key when the StartUid portion of the key does not have the expected 8-byte length. The raw key and parsed structure are reported via %q and %+v. Indicates a corrupt or malformed key; fix by correcting or regenerating the key data.

Source

Thrown at x/keys.go:580

	p.ByteType = k[0]
	k = k[1:]

	switch p.ByteType {
	case ByteData, ByteReverse:
		if len(k) < 8 {
			return p, errors.Errorf("uid length < 8 for key: %q, parsed key: %+v", key, p)
		}
		p.Uid = binary.BigEndian.Uint64(k)
		if p.Uid == 0 {
			return p, errors.Errorf("Invalid UID with value 0 for key: %v", key)
		}
		if !p.HasStartUid {
			break
		}

		if len(k) != 16 {
			return p, errors.Errorf("StartUid length != 8 for key: %q, parsed key: %+v", key, p)
		}

		k = k[8:]
		p.StartUid = binary.BigEndian.Uint64(k)
	case ByteIndex:
		if !p.HasStartUid {
			p.Term = string(k)
			break
		}

		if len(k) < 8 {
			return p, errors.Errorf("StartUid length < 8 for key: %q, parsed key: %+v", key, p)
		}

		term := k[:len(k)-8]
		startUid := k[len(k)-8:]
		p.Term = string(term)
		p.StartUid = binary.BigEndian.Uint64(startUid)

View on GitHub (pinned to 759e242be6)

Solutions

1. Verify the key is exactly 16 bytes for start-uid data keys (hex.Dump the key)
2. Regenerate the key using the package's key-construction helpers
3. Check for version skew between nodes/writers encoding keys
4. If from disk, suspect corruption and restore from backup

Example fix

// before: 12-byte data key with start uid
key := buf[:12]
p, err := x.Parse(key) // StartUid length != 8
// after
key := buf[:16] // 8-byte UID + 8-byte StartUid
p, err := x.Parse(key)

if len(key) != 17 { return fmt.Errorf("data+startuid key must be 17 bytes, got %d", len(key)) }
ok, err := x.IsDropOpKey(key)

func isStartUidDataKey(key []byte) bool { return len(key) == 17 }

When it happens

Trigger: Calling Parse/IsDropOpKey with a ByteData or ByteReverse key of length != 16 where HasStartUid is true (the key's type byte indicates start-uid layout).

Common situations: Truncated keys from corrupted storage, manually assembled byte keys of the wrong length, or version-mismatched key encodings between Dgraph components.

Related errors

• Invalid UID with value 0 for key: %v
• StartUid length < 8 for key: %q, parsed key: %+v
• count length < 4 for key: %q, parsed key: %+v
• Invalid data type
• could not parse key %s

AI-assisted analysis of dgraph-io/dgraph@759e242be6 (2026-09-01). Data as JSON: /api/errors/5aaf84d931b96fe9. Report an issue: GitHub.