apache/iceberg · error

Unsupported type for fromPartitionString: + type

Error message

Unsupported type for fromPartitionString: + type

What it means

Conversions.fromPartitionString converts a human-readable partition string (e.g. from a path or predicate) into the internal Java value for a primitive type. Only a fixed set of types (boolean, int, long, float, double, string, uuid, fixed/binary, decimal, date) is supported; any other primitive type (notably timestamp/timestamptz and unknown types) throws UnsupportedOperationException.

Source

Thrown at api/src/main/java/org/apache/iceberg/types/Conversions.java:76

      case FLOAT:
        return Float.valueOf(asString);
      case DOUBLE:
        return Double.valueOf(asString);
      case STRING:
        return asString;
      case UUID:
        return UUID.fromString(asString);
      case FIXED:
        Types.FixedType fixed = (Types.FixedType) type;
        return Arrays.copyOf(asString.getBytes(StandardCharsets.UTF_8), fixed.length());
      case BINARY:
        return asString.getBytes(StandardCharsets.UTF_8);
      case DECIMAL:
        return new BigDecimal(asString);
      case DATE:
        return Literal.of(asString).to(Types.DateType.get()).value();
      default:
        throw new UnsupportedOperationException(
            "Unsupported type for fromPartitionString: " + type);
    }
  }

  private static final ThreadLocal<CharsetEncoder> ENCODER =
      ThreadLocal.withInitial(StandardCharsets.UTF_8::newEncoder);
  private static final ThreadLocal<CharsetDecoder> DECODER =
      ThreadLocal.withInitial(StandardCharsets.UTF_8::newDecoder);

  public static ByteBuffer toByteBuffer(Type type, Object value) {
    return toByteBuffer(type.typeId(), value);
  }

  public static ByteBuffer toByteBuffer(Type.TypeID typeId, Object value) {
    if (value == null) {
      return null;
    }

View on GitHub (pinned to 86d9c8fc54)

Solutions

1. Convert the string to a java.time.LocalDateTime/Instant yourself and use Literal.of(...).to(type) to get the typed value
2. Only call fromPartitionString for supported types; check type.typeId() first
3. For timestamp partitions convert the string to epoch micros manually before writing

Example fix

// before
Object v = Conversions.fromPartitionString(Types.TimestampType.withZone(), "2023-01-01T00:00:00");
// after
long micros = Literal.of("2023-01-01T00:00:00").to(Types.TimestampType.withoutZone()).value(); // convert to epoch micros yourself

Set<Type.TypeID> ok = Set.of(BOOLEAN, INTEGER, LONG, FLOAT, DOUBLE, STRING, UUID, FIXED, BINARY, DECIMAL, DATE);
if (!ok.contains(type.typeId())) throw new IllegalArgumentException("fromPartitionString unsupported for: " + type);

boolean supportsFromString(Type t) { return EnumSet.of(TypeID.BOOLEAN, TypeID.INTEGER, TypeID.LONG, TypeID.FLOAT, TypeID.DOUBLE, TypeID.STRING, TypeID.UUID, TypeID.FIXED, TypeID.BINARY, TypeID.DECIMAL, TypeID.DATE).contains(t.typeId()); }

try { v = Conversions.fromPartitionString(type, s); } catch (UnsupportedOperationException e) { v = convertManually(type, s); }

When it happens

Trigger: Partition string parsing for a partition field whose type is TIMESTAMP, TIMESTAMPTZ, TIME, UNKNOWN, or a geo type; passing a non-primitive type to fromPartitionString.

Common situations: Manual partition-value parsing of tables partitioned by timestamp transforms; tools reconstructing data file paths for newer spec types.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Identity transform is not supported
• Bucket transform is not supported
• Truncate transform is not supported
• Cannot bind unsupported transform: %s
• Cannot serialize type: + typeId

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/a3b70c6c94276c61. Report an issue: GitHub.