apache/iceberg · error · IllegalArgumentException

Unsupported data statistics type: ${statisticsType}

Error message

Unsupported data statistics type: ${statisticsType}

What it means

DataStatisticsSerializer.copy supports copying statistics objects of known StatisticsType values; when the type is neither Map nor Sketch it cannot pick a copy strategy and throws. The type comes from the DataStatistics object being copied, so an unsupported value implies an unknown/newer statistics implementation.

Source

Thrown at flink/v2.1/flink/src/main/java/org/apache/iceberg/flink/sink/shuffle/DataStatisticsSerializer.java:91

  public DataStatistics copy(DataStatistics obj) {
    StatisticsType statisticsType = obj.type();
    if (statisticsType == StatisticsType.Map) {
      MapDataStatistics from = (MapDataStatistics) obj;
      Map<SortKey, Long> fromStats = (Map<SortKey, Long>) from.result();
      Map<SortKey, Long> toStats = Maps.newHashMap(fromStats);
      return new MapDataStatistics(toStats);
    } else if (statisticsType == StatisticsType.Sketch) {
      // because ReservoirItemsSketch doesn't expose enough public methods for cloning,
      // this implementation adopted the less efficient serialization and deserialization.
      SketchDataStatistics from = (SketchDataStatistics) obj;
      ReservoirItemsSketch<SortKey> fromStats = (ReservoirItemsSketch<SortKey>) from.result();
      byte[] bytes = fromStats.toByteArray(sketchSerializer);
      Memory memory = Memory.wrap(bytes);
      ReservoirItemsSketch<SortKey> toStats =
          ReservoirItemsSketch.heapify(memory, sketchSerializer);
      return new SketchDataStatistics(toStats);
    } else {
      throw new IllegalArgumentException("Unsupported data statistics type: " + statisticsType);
    }
  }

  @Override
  public DataStatistics copy(DataStatistics from, DataStatistics reuse) {
    // not much benefit to reuse
    return copy(from);
  }

  @Override
  public int getLength() {
    return -1;
  }

  @SuppressWarnings("unchecked")
  @Override
  public void serialize(DataStatistics obj, DataOutputView target) throws IOException {
    StatisticsType statisticsType = obj.type();

View on GitHub (pinned to 86d9c8fc54)

Solutions

1. Align Iceberg connector versions on all nodes of the Flink job.
2. Only feed DataStatistics instances produced by this serializer/connector (Map or Sketch types).
3. Upgrade the connector so newer statistics types are recognized.

StatisticsType t = from.type();
if (t != StatisticsType.Map && t != StatisticsType.Sketch) {
  throw new IllegalArgumentException("Cannot copy statistics of type " + t);
}

boolean isCopyable(DataStatistics s) {
  return s.type() == StatisticsType.Map || s.type() == StatisticsType.Sketch;
}

try {
  DataStatistics copy = serializer.copy(from, null);
} catch (IllegalArgumentException e) {
  if (e.getMessage().startsWith("Unsupported data statistics type")) {
    // fall back to map-based statistics or re-create from raw data
  } else throw e;
}

When it happens

Trigger: Calling copy() on a DataStatistics whose type() returns a StatisticsType other than Map or Sketch, e.g. a statistics object created by a newer connector version.

Common situations: Mixed connector versions across the Flink cluster during the data-statistics shuffle handshake, or custom DataStatistics implementations passed into the serializer.

Related errors

• Fail to serialize data statistics
• Fail to serialize aggregated statistics
• The Avro schema is not a nullable type: ${schema}
• Fail to serialize at field: %s.
• Unrecognized version or corrupt state: <version>

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/11c9b2117bc56508. Report an issue: GitHub.