apache/iceberg · error · UnsupportedOperationException

Unsupported type: " + type

Error message

Unsupported type: " + type

What it means

RowDataToAvroConverters.createConverter (public) builds RowData-to-Avro converters. For TIMESTAMP_WITH_LOCAL_TIME_ZONE with legacyTimestampMapping=true, no Avro encoder path exists, so it throws UnsupportedOperationException("Unsupported type: " + type). Legacy timestamp mapping cannot serialize local-zoned timestamps to Avro.

Source

Thrown at flink/v2.2/flink/src/main/java/org/apache/iceberg/flink/formats/avro/RowDataToAvroConverters.java:223

                  } else {
                    // Iceberg: Added support for nanoseconds precision (FLINK-39251)
                    return instant.getEpochSecond() * 1_000_000_000L + instant.getNano();
                  }
                }
              };
        }
        break;
        // Iceberg: Added support for nanoseconds precision (FLINK-39251)
      case TIMESTAMP_WITH_LOCAL_TIME_ZONE:
        final int ltzPrecision;
        if (type instanceof org.apache.flink.table.types.logical.LocalZonedTimestampType) {
          ltzPrecision =
              ((org.apache.flink.table.types.logical.LocalZonedTimestampType) type).getPrecision();
        } else {
          ltzPrecision = 3;
        }
        if (legacyTimestampMapping) {
          throw new UnsupportedOperationException("Unsupported type: " + type);
        } else {
          converter =
              new RowDataToAvroConverter() {
                private static final long serialVersionUID = 1L;

                @Override
                public Object convert(Schema schema, Object object) {
                  TimestampData timestampData = (TimestampData) object;
                  if (ltzPrecision <= 3) {
                    return timestampData.getMillisecond();
                  } else if (ltzPrecision <= 6) {
                    return timestampData.getMillisecond() * 1000L
                        + timestampData.getNanoOfMillisecond() / 1000;
                  } else {
                    // Iceberg: Added support for nanoseconds precision (FLINK-39251)
                    return timestampData.getMillisecond() * 1_000_000L
                        + timestampData.getNanoOfMillisecond();
                  }

View on GitHub (pinned to 86d9c8fc54)

Solutions

1. Disable legacy timestamp mapping so the non-legacy LTZ converter is used.
2. Change the column to TIMESTAMP_WITHOUT_TIME_ZONE if timezone semantics allow.
3. Convert the RowData field (e.g. to a long epoch value) before Avro serialization.

Example fix

// before
// legacyTimestampMapping=true, column TIMESTAMP_WITH_LOCAL_TIME_ZONE(6)
// after
// set legacy timestamp mapping off (or use DataTypes.TIMESTAMP_WITHOUT_TIME_ZONE(6))

// before writing, reject LTZ columns under legacy mapping
if (legacyTimestampMapping && rowType.getTypeAt(i) instanceof LocalZonedTimestampType) { throw new IllegalArgumentException("Disable legacy timestamp mapping to write TIMESTAMP_WITH_LOCAL_TIME_ZONE to Avro"); }

try { avroConverter.convert(rowData); } catch (UnsupportedOperationException e) { /* disable legacy mapping or convert the column first */ }

When it happens

Trigger: Writing RowData to Avro (e.g. Avro serialization format or Iceberg Avro file writer) when the schema contains TIMESTAMP_WITH_LOCAL_TIME_ZONE and legacy timestamp mapping is enabled — the ltzPrecision lookup shows the type reached the LTZ branch but legacy mode is on.

Common situations: Jobs configured with legacy timestamp mapping (pre-FLIP-278 options) writing timestamp-with-local-time-zone columns; tables/options migrated from older Flink versions retaining legacy config.

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: ${type}
• Unsupported type: ${type}
• Unsupported to derive Schema for type: ${logicalType}
• Unsupported type: " + type
• Unsupported to derive Schema for type:

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/dead7c209bfb4c52. Report an issue: GitHub.