apache/flink · error · RuntimeException

Fail to serialize at field: %s.

Error message

Fail to serialize at field: %s.

What it means

Error "Fail to serialize at field: %s." thrown in apache/flink.

Source

Thrown at flink-formats/flink-csv/src/main/java/org/apache/flink/formats/csv/RowDataToCsvConverters.java:111

                        .map(RowType.RowField::getType)
                        .toArray(LogicalType[]::new);
        final String[] fieldNames = type.getFieldNames().toArray(new String[0]);
        final RowFieldConverter[] fieldConverters =
                Arrays.stream(fieldTypes)
                        .map(RowDataToCsvConverters::createNullableRowFieldConverter)
                        .toArray(RowFieldConverter[]::new);
        final int rowArity = type.getFieldCount();
        return (row, context) -> {
            // top level reuses the object node container
            final ObjectNode objectNode = (ObjectNode) context.container;
            for (int i = 0; i < rowArity; i++) {
                try {
                    objectNode.set(
                            fieldNames[i],
                            fieldConverters[i].convert(
                                    context.csvMapper, context.container, row, i));
                } catch (Throwable t) {
                    throw new RuntimeException(
                            String.format("Fail to serialize at field: %s.", fieldNames[i]), t);
                }
            }
            return objectNode;
        };
    }

    private static RowFieldConverter createNullableRowFieldConverter(LogicalType fieldType) {
        final RowFieldConverter fieldConverter = createRowFieldConverter(fieldType);
        return (csvMapper, container, row, pos) -> {
            if (row.isNullAt(pos)) {
                return container.nullNode();
            }
            return fieldConverter.convert(csvMapper, container, row, pos);
        };
    }

    private static RowFieldConverter createRowFieldConverter(LogicalType fieldType) {

View on GitHub (pinned to 2f3c205e92)

Solutions

1. Address the cause reported by the error message: Fail to serialize at field: the reported value.
2. Verify the inputs, configuration values, and classpath/dependency setup related to this operation, then retry.

Example fix

Correct the condition described ("Fail to serialize at field: the reported value.") and rerun the job or command.

When it happens

Trigger: Triggered at runtime when the operation fails because: Fail to serialize at field: the reported value.

Common situations: Commonly caused by misconfiguration, missing dependencies or files, unsupported types or operations, or invalid user input leading to: Fail to serialize at field: the reported value.

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/cd0312094d919850. Report an issue: GitHub.