prestodb/presto · error · RuntimeException

Unknown primitive type:

Error message

Unknown primitive type: 

What it means

SerDeUtils.serializePrimitive switches over Hive primitive object inspector categories (boolean, byte, short, int, long, float, double, string, varchar, char, date, timestamp, decimal, binary...). A primitive category with no case in the switch falls through to a RuntimeException('Unknown primitive type: ...'). A new or exotic Hive primitive is not handled by this serializer.

Source

Thrown at presto-hive/src/main/java/com/facebook/presto/hive/util/SerDeUtils.java:166

                return;
            case TIMESTAMP:
                TimestampType.TIMESTAMP.writeLong(builder, formatTimestampAsLong(object, (TimestampObjectInspector) inspector, hiveStorageTimeZone, legacyTimestampEnabled));
                return;
            case BINARY:
                VARBINARY.writeSlice(builder, Slices.wrappedBuffer(((BinaryObjectInspector) inspector).getPrimitiveJavaObject(object)));
                return;
            case DECIMAL:
                DecimalType decimalType = (DecimalType) type;
                HiveDecimalWritable hiveDecimal = ((HiveDecimalObjectInspector) inspector).getPrimitiveWritableObject(object);
                if (decimalType.isShort()) {
                    decimalType.writeLong(builder, DecimalUtils.getShortDecimalValue(hiveDecimal, decimalType.getScale()));
                }
                else {
                    decimalType.writeSlice(builder, DecimalUtils.getLongDecimalValue(hiveDecimal, decimalType.getScale()));
                }
                return;
        }
        throw new RuntimeException("Unknown primitive type: " + inspector.getPrimitiveCategory());
    }

    private static Block serializeList(Type type, BlockBuilder builder, Object object, ListObjectInspector inspector, DateTimeZone hiveStorageTimeZone, boolean legacyTimestampEnabled)
    {
        List<?> list = inspector.getList(object);
        if (list == null) {
            requireNonNull(builder, "parent builder is null").appendNull();
            return null;
        }

        List<Type> typeParameters = type.getTypeParameters();
        checkArgument(typeParameters.size() == 1, "list must have exactly 1 type parameter");
        Type elementType = typeParameters.get(0);
        ObjectInspector elementInspector = inspector.getListElementObjectInspector();
        BlockBuilder currentBuilder;
        if (builder != null) {
            currentBuilder = builder.beginBlockEntry();
        }

View on GitHub (pinned to 55bb57d202)

Solutions

1. Identify the primitive category printed in the message and check which table/column produces it
2. Fix the table schema to use standard Hive primitives (e.g. replace void columns)
3. Upgrade Presto to a version handling that primitive category
4. Patch/extend serializePrimitive if you maintain a fork and the type is legitimate

Example fix

// before
-- column shows up as void/unknown primitive in metastore
// after
ALTER TABLE t REPLACE COLUMNS (col string); -- use a supported primitive type

// verify the primitive category is handled before serializing
PrimitiveObjectInspector.PrimitiveCategory pc = inspector.getPrimitiveCategory();
Set<PrimitiveCategory> supported = EnumSet.of(BOOLEAN, BYTE, SHORT, INT, LONG, FLOAT, DOUBLE,
    STRING, VARCHAR, CHAR, DATE, TIMESTAMP, DECIMAL, BINARY);
if (!supported.contains(pc)) {
    throw new PrestoException(NOT_SUPPORTED, "Unsupported primitive: " + pc);
}

boolean isSupportedPrimitive(PrimitiveObjectInspector inspector) {
    return inspector.getPrimitiveCategory() != PrimitiveCategory.UNKNOWN
        && inspector.getPrimitiveCategory() != PrimitiveCategory.VOID;
}

try {
    block = SerDeUtils.serializeObject(...);
} catch (RuntimeException e) {
    if (e.getMessage() != null && e.getMessage().startsWith("Unknown primitive type")) {
        LOG.error("Unhandled Hive primitive: " + e.getMessage());
    }
    throw e;
}

When it happens

Trigger: serializeObject dispatches a PRIMITIVE inspector whose PrimitiveObjectInspector.PrimitiveCategory lacks a case branch in serializePrimitive — e.g. hive void/unknown or a newer Hive primitive added by the SerDe.

Common situations: Reading tables with unusual primitive columns (e.g. void from corrupt schema); SerDe/third-party storage handler returning a novel primitive category; Hive version mismatch introducing new primitive types.

Related errors

• Unknown object inspector category:
• Unexpected column type
• unsupported string field type:
• Unsupported column type:
• unknown java type

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/2d10e412c847cc5e. Report an issue: GitHub.