prestodb/presto · error · VerifyError

Unsupported type

Error message

Unsupported type 

What it means

readNonNullBlock decodes a direct data stream into blocks based on the column's type, supporting BigintType, IntegerType, and SmallintType. Any other type reaching this reader is unsupported and triggers VerifyError("Unsupported type " + type), indicating the stream reader was constructed for a type it cannot decode — a logic/metadata mismatch rather than data corruption.

Source

Thrown at presto-orc/src/main/java/com/facebook/presto/orc/reader/LongDirectBatchStreamReader.java:188

        if (type instanceof TimeType) {
            long[] values = new long[nextBatchSize];
            dataStream.next(values, nextBatchSize);
            for (int i = 0; i < values.length; i++) {
                values[i] = convertUnits.apply(values[i]);
            }
            return new LongArrayBlock(nextBatchSize, Optional.empty(), values);
        }
        if (type instanceof IntegerType || type instanceof DateType) {
            int[] values = new int[nextBatchSize];
            dataStream.next(values, nextBatchSize);
            return new IntArrayBlock(nextBatchSize, Optional.empty(), values);
        }
        if (type instanceof SmallintType) {
            short[] values = new short[nextBatchSize];
            dataStream.next(values, nextBatchSize);
            return new ShortArrayBlock(nextBatchSize, Optional.empty(), values);
        }
        throw new VerifyError("Unsupported type " + type);
    }

    private Block readNullBlock(boolean[] isNull, int nonNullCount)
            throws IOException
    {
        if (type instanceof BigintType) {
            return longReadNullBlock(isNull, nonNullCount);
        }
        if (type instanceof TimeType) {
            return longReadNullBlock(isNull, nonNullCount);
        }
        if (type instanceof IntegerType || type instanceof DateType) {
            return intReadNullBlock(isNull, nonNullCount);
        }
        if (type instanceof SmallintType) {
            return shortReadNullBlock(isNull, nonNullCount);
        }
        throw new VerifyError("Unsupported type " + type);

View on GitHub (pinned to 55bb57d202)

Solutions

1. Fix the reader factory so the type is mapped to a matching stream reader (e.g. use LongStreamReader or DateStreamReader for DATE)
2. Ensure all nodes run the same Presto version to avoid inconsistent type mapping
3. Check for custom connectors/plugins overriding type-to-reader mappings and correct them
4. Upgrade Presto if the type support was added in a newer release

Example fix

// before
return new LongDirectBatchStreamReader(type, ...); // type = DateType
// after
return new LongStreamReader.StreamReaderFactory(type, ...); // reader matching the declared type

// Java: before constructing the reader
if (!(type instanceof BigintType) && !(type instanceof IntegerType) && !(type instanceof SmallintType)) {
    throw new PrestoException(NOT_SUPPORTED, "Type not supported by long stream reader: " + type);
}

// Java narrowing helper
static boolean supportedByLongReader(Type t) {
    return t instanceof BigintType || t instanceof IntegerType || t instanceof SmallintType;
}

// Cannot meaningfully catch VerifyError; prevent instead:
// if (!supportedByLongReader(type)) { use reader factory for type; }

When it happens

Trigger: readBlock -> readNonNullBlock with a type other than BIGINT/INTEGER/SMALLINT (e.g. DateType or a custom type) mapped onto LongDirectBatchStreamReader.

Common situations: Plugin/connector code creating the wrong stream reader for a type; engine changes mapping new types to the long reader; version skew between Presto nodes (mixed coordinator/worker builds) causing inconsistent type mappings.

Related errors

• Unsupported type:
• NOT_SUPPORTED
• NOT_SUPPORTED
• Invalid array block:
• Invalid map block:

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/d0cfe1f7a8a3b5b8. Report an issue: GitHub.