apache/iceberg · error · java.lang.UnsupportedOperationException

Not a supported type:

Error message

Not a supported type: 

What it means

This is the fallback branch of SparkTypeToType.atomic: a Spark type reached the converter that has no Iceberg mapping (it is not boolean, numeric, decimal, binary, geometry, geography, or null-type). The UnsupportedOperationException reports the unsupported Spark type's catalogString. It prevents silent mis-typing of Spark data in Iceberg schemas.

Source

Thrown at spark/v4.2/spark/src/main/java/org/apache/iceberg/spark/SparkTypeToType.java:188

    } else if (atomic instanceof GeometryType) {
      GeometryType geometry = (GeometryType) atomic;
      if (geometry.isMixedSrid()) {
        throw new UnsupportedOperationException(
            "Cannot convert Spark geometry with mixed SRID to Iceberg");
      }
      return Types.GeometryType.of(geometry.crs());
    } else if (atomic instanceof GeographyType) {
      GeographyType geography = (GeographyType) atomic;
      if (geography.isMixedSrid()) {
        throw new UnsupportedOperationException(
            "Cannot convert Spark geography with mixed SRID to Iceberg");
      }
      return Types.GeographyType.of(geography.crs(), convertAlgorithm(geography.algorithm()));
    } else if (atomic instanceof NullType) {
      return Types.UnknownType.get();
    }

    throw new UnsupportedOperationException("Not a supported type: " + atomic.catalogString());
  }

  // Translates Spark's edge-interpolation algorithm to Iceberg's, mirroring
  // TypeToSparkType#convertAlgorithm. Spark supports only the spherical algorithm today; anything
  // else is rejected loudly rather than silently defaulting, so a new Spark algorithm surfaces here
  // instead of being dropped.
  private static EdgeAlgorithm convertAlgorithm(EdgeInterpolationAlgorithm algorithm) {
    switch (algorithm.toString().toUpperCase(Locale.ROOT)) {
      case "SPHERICAL":
        return EdgeAlgorithm.SPHERICAL;
      default:
        throw new UnsupportedOperationException(
            "Iceberg does not support Spark geography edge algorithm: " + algorithm);
    }
  }
}

View on GitHub (pinned to 86d9c8fc54)

Solutions

1. Upgrade iceberg-spark to a version whose type converter supports the Spark type
2. Cast or drop the unsupported column to a supported type (e.g. cast to string/binary) before conversion
3. Wrap the offending type in a supported equivalent upstream
4. If the type should be supported, file/port support for it in the converter

Example fix

// before
Types.IcebergType t = new SparkTypeToType().convert(sparkTypeWithUnsupportedType); // throws
// after
df = df.drop("unsupportedCol");
Types.IcebergType t = new SparkTypeToType().convert(df.schema());

boolean convertible = dt instanceof BooleanType || dt instanceof NumericType
    || dt instanceof DecimalType || dt instanceof BinaryType
    || dt instanceof GeometryType || dt instanceof GeographyType || dt instanceof NullType;

if (!convertible) {
  throw new IllegalStateException("Unsupported Spark type for Iceberg: " + dt.catalogString());
}

try {
  icebergType = converter.convert(sparkSchema);
} catch (UnsupportedOperationException e) {
  if (e.getMessage().startsWith("Not a supported type:")) {
    // cast/drop the offending column and retry
  }
}

When it happens

Trigger: Converting a schema containing exotic/unsupported Spark atomic types into an Iceberg Type via SparkTypeToType.convert.

Common situations: Newer Spark types not yet mapped in the Iceberg version in use; custom Spark types from third-party plugins; using an outdated iceberg-spark build against a newer Spark release introducing new types.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• Spark does not support time fields
• Cannot convert unsupported type to Spark: ${primitive}
• Spark does not support time fields
• Unsupported type:
• Encountered an unsupported ORC type during a write from Spar

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/58dc6ddf0a3042b1. Report an issue: GitHub.