apache/seatunnel · error · IndexOutOfBoundsException

The data does not match the configured schema information…

Error message

The data does not match the configured schema information, please check

What it means

CsvSerializationSchema.serialize validates that the row's field count equals the configured SeaTunnelRowType's total fields; otherwise it throws IndexOutOfBoundsException telling the user the data does not match the schema. CSV writing is positional, so field count must match the declared columns exactly.

Solutions

Align the sink schema (catalog table / schema option) with the actual row field count of the upstream data.
Insert a transform to add missing columns with defaults or drop extra columns before the CSV sink.
Log/inspect one upstream SeaTunnelRow (fields.length) and compare with the configured schema's total fields.

Example fix

// before: sink schema has 3 columns but row has 4 fields
// after: add the 4th column to the sink schema or use a FieldMapper transform to drop it

Defensive patterns

Strategy: validation

Validate before calling

if (row.getFields().length != rowType.getTotalFields()) { throw new IllegalStateException("row/schema field count mismatch"); }

Try / catch

try { sink.write(row); } catch (IndexOutOfBoundsException e) { /* fix upstream schema mapping */ }

Prevention

Keep source, transform, and sink schemas in sync
Add a schema-check unit test between pipeline stages
Use FieldMapper to enforce exact column counts before the sink

When it happens

Trigger: Upstream source/transform emits a SeaTunnelRow with fewer or more fields than declared in the sink schema (schema drift, added/dropped columns, wrong catalog_table mapping).

Common situations: Adding a column to the source without updating the CSV sink schema; transform (e.g. SQL/FieldMapper) changing column count; schema evolution between source and sink.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/d88346ae7f8b5823. Report an issue: GitHub.

Appendix: source

Thrown at seatunnel-formats/seatunnel-format-csv/src/main/java/org/apache/seatunnel/format/csv/CsvSerializationSchema.java:176

        public CsvSerializationSchema build() {
            return new CsvSerializationSchema(
                    seaTunnelRowType,
                    separators,
                    dateFormatter,
                    dateTimeFormatter,
                    timeFormatter,
                    charset,
                    nullValue,
                    quoteMode,
                    wallClockTimestampTz);
        }
    }

    @Override
    public byte[] serialize(SeaTunnelRow element) {
        if (element.getFields().length != seaTunnelRowType.getTotalFields()) {
            throw new IndexOutOfBoundsException(
                    "The data does not match the configured schema information, please check");
        }
        Object[] fields = element.getFields();
        String[] strings = new String[fields.length];
        for (int i = 0; i < fields.length; i++) {
            strings[i] = convert(fields[i], seaTunnelRowType.getFieldType(i), 0);
        }
        return String.join(separators[0], strings).getBytes(charset);
    }

    private String convert(Object field, SeaTunnelDataType<?> fieldType, int level) {
        if (field == null) {
            return nullValue;
        }
        switch (fieldType.getSqlType()) {
            case DOUBLE:
            case FLOAT:
            case INT:

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