dgraph-io/dgraph · error

count length < 4 for key: %q, parsed key: %+v

Error message

count length < 4 for key: %q, parsed key: %+v

What it means

Error returned by x/keys.go while parsing a key when fewer than 4 bytes remain for the count field. The raw key and parsed structure are reported via %q and %+v. Indicates a truncated or malformed key; fix by correcting or regenerating the key data.

Source

Thrown at x/keys.go:601

		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)
	case ByteCount, ByteCountRev:
		if len(k) < 4 {
			return p, errors.Errorf("count length < 4 for key: %q, parsed key: %+v", key, p)
		}
		p.Count = binary.BigEndian.Uint32(k)

		if !p.HasStartUid {
			break
		}

		if len(k) != 12 {
			return p, errors.Errorf("StartUid length != 8 for key: %q, parsed key: %+v", key, p)
		}

		k = k[4:]
		p.StartUid = binary.BigEndian.Uint64(k)
	default:
		// Some other data type.
		return p, errors.Errorf("Invalid data type")
	}
	return p, nil

View on GitHub (pinned to 759e242be6)

Solutions

1. Verify the key payload is >= 4 bytes with hex.Dump
2. Rebuild the key with the count-key construction helper
3. Audit the code path that wrote the key for truncation
4. Restore affected data from a backup if on-disk corruption

Example fix

// before: count key without 4-byte count
key := []byte{byte(x.ByteCount)}
p, err := x.Parse(key) // count length < 4
// after
key := x.CountKey(attr, term, startUid) // includes 4-byte count
p, err := x.Parse(key)

if len(key) < 5 { return fmt.Errorf("count key too short: %d", len(key)) }
ok, err := x.IsDropOpKey(key)

func isMinCountKey(key []byte) bool { return len(key) >= 5 }

When it happens

Trigger: Calling Parse/IsDropOpKey with a ByteCount or ByteCountRev key whose payload is shorter than 4 bytes.

Common situations: Corrupted count index entries in storage, hand-built keys missing the 4-byte count, or truncated data from a faulty migration/backup restore.

Related errors

• Invalid UID with value 0 for key: %v
• StartUid length != 8 for key: %q, parsed key: %+v
• StartUid length < 8 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/cafb748d37940a47. Report an issue: GitHub.