VictoriaMetrics/VictoriaMetrics · error

cannot read AccountID

Error message

cannot read AccountID

What it means

MetricMetadata field 11 is 'AccountID' (uint32, a VictoriaMetrics extension field). fc.Uint32() returns ok=false when the field bytes are not a valid varint or the buffer ends mid-value. The library reports 'cannot read AccountID', indicating this extension field was encoded with a wrong wire type or truncated.

Source

Thrown at lib/prompb/write_request_unmarshaler.go:695

				return fmt.Errorf("cannot read metric family name")
			}
			mm.MetricFamilyName = value
		case 4:
			value, ok := fc.String()
			if !ok {
				return fmt.Errorf("cannot read help")
			}
			mm.Help = value
		case 5:
			value, ok := fc.String()
			if !ok {
				return fmt.Errorf("cannot read unit")
			}
			mm.Unit = value
		case 11:
			value, ok := fc.Uint32()
			if !ok {
				return fmt.Errorf("cannot read AccountID")
			}
			mm.AccountID = value
		case 12:
			value, ok := fc.Uint32()
			if !ok {
				return fmt.Errorf("cannot read ProjectID")
			}
			mm.ProjectID = value
		}
	}
	return nil
}

View on GitHub (pinned to 5079fb58f1)

Solutions

1. Encode AccountID as a uint32 varint (field 11) per the VM-extended MetricMetadata schema.
2. Regenerate the sender from the VictoriaMetrics prompb .proto so extension fields match.
3. Check the body for truncation before decoding.
4. Return 400 and log the payload region around the failure.

Example fix

// sender side: before — AccountID as bytes
buf.EncodeStringBytes(11, []byte(accountID))

// after — uint32 varint
buf.EncodeUint32(11, mm.AccountID)

// VM extension fields: validate tenant IDs fit uint32 before encoding
func validAccountID(id uint32) bool {
    return id > 0
}
if !validAccountID(mm.AccountID) {
    return errors.New("AccountID must be a positive uint32")
}

func isVarintUint32Field(b []byte, fieldNum int) bool {
    if len(b) < 1 {
        return false
    }
    tag := b[0]
    return int(tag>>3) == fieldNum && tag&0x7 == 0
}

if err := wr.Unmarshal(body); err != nil {
    if strings.Contains(err.Error(), "cannot read AccountID") {
        http.Error(w, "invalid AccountID encoding in metadata", http.StatusBadRequest)
        return
    }
    return err
}

When it happens

Trigger: AccountID encoded as fixed32/bytes instead of varint, truncated buffer at field 11, or a sender mixing Prometheus-generated metadata (no fields 11/12) with a VictoriaMetrics-specific encoder.

Common situations: Cluster tenants sending custom-encoded metadata, truncated bodies in multi-tenant gateways, hand-rolled serializers writing the AccountID with the wrong type.

Related errors

• cannot read ProjectID
• cannot read sample value
• cannot read sample timestamp
• cannot read metric type
• cannot read metric family name

AI-assisted analysis of VictoriaMetrics/VictoriaMetrics@5079fb58f1 (2026-09-03). Data as JSON: /api/errors/ed67b0ed2c29c6b9. Report an issue: GitHub.