apache/iceberg · error · java.lang.UnsupportedOperationException

Unsupported type:

Error message

Unsupported type: 

What it means

In FlinkParquetReaders' ReadBuilder, the primitive(...) factory maps Parquet primitive columns to Flink value readers. If a column has a logical-type annotation it is handled by the visitor; for unannotated primitives only the known parquet primitive types are supported, and anything else hits the default branch throwing UnsupportedOperationException naming the primitive.

Source

Thrown at flink/v2.3/flink/src/main/java/org/apache/iceberg/flink/data/FlinkParquetReaders.java:342

          return new ParquetValueReaders.ByteArrayReader(desc);
        case INT32:
          if (expected.typeId() == org.apache.iceberg.types.Type.TypeID.LONG) {
            return new ParquetValueReaders.IntAsLongReader(desc);
          } else {
            return new ParquetValueReaders.UnboxedReader<>(desc);
          }
        case FLOAT:
          if (expected.typeId() == org.apache.iceberg.types.Type.TypeID.DOUBLE) {
            return new ParquetValueReaders.FloatAsDoubleReader(desc);
          } else {
            return new ParquetValueReaders.UnboxedReader<>(desc);
          }
        case BOOLEAN:
        case INT64:
        case DOUBLE:
          return new ParquetValueReaders.UnboxedReader<>(desc);
        default:
          throw new UnsupportedOperationException("Unsupported type: " + primitive);
      }
    }
  }

  private static class BinaryDecimalReader
      extends ParquetValueReaders.PrimitiveReader<DecimalData> {
    private final int precision;
    private final int scale;

    BinaryDecimalReader(ColumnDescriptor desc, int precision, int scale) {
      super(desc);
      this.precision = precision;
      this.scale = scale;
    }

    @Override
    public DecimalData read(DecimalData ignored) {
      Binary binary = column.nextBinary();

View on GitHub (pinned to 86d9c8fc54)

Solutions

1. Rewrite the Parquet data with standard types (e.g. convert INT96 to timestamp-millis/micros with INT64 annotation).
2. Ensure the requested Iceberg schema matches the file's supported primitives; avoid reading unsupported columns by projecting them out.
3. If a valid type is genuinely missing, extend ReadBuilder.primitive to add a reader case for it and contribute upstream.

Example fix

// before: reading legacy INT96 column directly
// after: rewrite file
// spark.sql.parquet.int96TimestampConversion=true; rewrite table so timestamps are INT64 (TIMESTAMP_MICROS)

// java
org.apache.parquet.schema.PrimitiveType pt = column.getPrimitiveType();
boolean readable = pt.getPrimitiveTypeName() == PrimitiveTypeName.BOOLEAN
    || pt.getPrimitiveTypeName() == PrimitiveTypeName.INT64
    || pt.getPrimitiveTypeName() == PrimitiveTypeName.DOUBLE
    || pt.getPrimitiveTypeName() == PrimitiveTypeName.INT32
    || pt.getPrimitiveTypeName() == PrimitiveTypeName.FLOAT
    || pt.getPrimitiveTypeName() == PrimitiveTypeName.BINARY
    || pt.getPrimitiveTypeName() == PrimitiveTypeName.FIXED_LEN_BYTE_ARRAY;

// java
try {
  ParquetValueReader<?> r = FlinkParquetReaders.buildReader(...);
} catch (UnsupportedOperationException e) {
  // log the offending primitive, fall back to a rewrite/re-read path
}

When it happens

Trigger: Reading a Parquet file whose column has a primitive type not covered by the switch (e.g. INT96 timestamps, or an annotated type the visitor declined) while using FlinkParquetReaders to build a reader for the file schema.

Common situations: Legacy Hive/Impala-written Parquet files using INT96 timestamps; exotic or newly added Parquet physical types; files written by tools with unusual column typing.

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

• Unsupported type: %s
• Unsupported logical type: ${primitive.getOriginalType()}
• Unsupported type: ${primitive}
• Unsupported base type for decimal: ${primitiveTypeName}
• Unsupported timestamp type: ${timestamps}

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/4721d2bd1b99e44c. Report an issue: GitHub.