apache/seatunnel · warning

DECIMAL precision {} exceeds maximum {}, truncating to {}

Error message

DECIMAL precision {} exceeds maximum {}, truncating to {}

What it means

Warning from DuckDBTypeConverter.handleDecimalType (via convert): the source DECIMAL's precision exceeds MAX_PRECISION supported by the DuckDB dialect, so precision is truncated to MAX_PRECISION. The converted column will declare the reduced precision, which can cause rounding or write failures if actual values need more digits.

Source

Thrown at seatunnel-connectors-v2/connector-jdbc/src/main/java/org/apache/seatunnel/connectors/seatunnel/jdbc/internal/dialect/duckdb/DuckDBTypeConverter.java:200

                builder.dataType(BasicType.STRING_TYPE);
                builder.columnLength(lengthValue > 0 ? lengthValue : 65535);
                break;
            default:
                log.warn("Unsupported DuckDB type: {}, falling back to STRING", duckDBType);
                builder.dataType(BasicType.STRING_TYPE);
                builder.columnLength(lengthValue > 0 ? lengthValue : 255);
        }
        return builder.build();
    }

    private void handleDecimalType(
            PhysicalColumn.PhysicalColumnBuilder builder, BasicTypeDefine typeDefine) {
        long precision =
                typeDefine.getPrecision() != null ? typeDefine.getPrecision() : DEFAULT_PRECISION;
        int scale = typeDefine.getScale() != null ? typeDefine.getScale() : DEFAULT_SCALE;

        if (precision > MAX_PRECISION) {
            log.warn(
                    "DECIMAL precision {} exceeds maximum {}, truncating to {}",
                    precision,
                    MAX_PRECISION,
                    MAX_PRECISION);
            precision = MAX_PRECISION;
        }
        if (scale < 0) {
            log.warn("DECIMAL scale {} is negative, setting to 0", scale);
            scale = 0;
        } else if (scale > MAX_SCALE) {
            log.warn(
                    "DECIMAL scale {} exceeds maximum {}, truncating to {}",
                    scale,
                    MAX_SCALE,
                    MAX_SCALE);
            scale = MAX_SCALE;
        }

View on GitHub (pinned to cf67b549a7)

Solutions

1. Cast the source column to a precision within the dialect maximum, e.g. CAST(col AS DECIMAL(38,6)).
2. Raise the sink column definition manually if you control schema creation.
3. Verify actual data range; if values never approach the max, the truncation is harmless.
4. Upgrade the connector if a newer version supports higher precision.

Example fix

// before
SELECT amount FROM ledger; -- DECIMAL(45,10)
// after
SELECT CAST(amount AS DECIMAL(38,10)) AS amount FROM ledger;

for (Column c : columns) {
  if (c.getDataType() instanceof DecimalType) {
    long p = ((DecimalType) c.getDataType()).getPrecision();
    if (p > MAX_PRECISION) throw new IllegalArgumentException(
      "Column " + c.getName() + " precision " + p + " exceeds " + MAX_PRECISION);
  }
}

boolean isDuckDbSafeDecimal(DecimalType t) {
  return t.getPrecision() > 0 && t.getPrecision() <= MAX_PRECISION;
}

When it happens

Trigger: Calling convert on a BasicTypeDefine with getPrecision() > the dialect's MAX_PRECISION (e.g. DECIMAL(40,10) from a source table).

Common situations: Syncing DECIMAL columns from engines that allow larger precision (e.g. some sources allow up to 38+ or unbounded) into DuckDB via catalog-driven schema mapping.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

• The decimal column {} type decimal({},{}) is out of range, w
• DECIMAL scale {} is negative, setting to 0
• DECIMAL scale {} exceeds maximum {}, truncating to {}
• The decimal column {} type decimal({},{}) is out of range, w
• The decimal column {} type decimal({},{}) is out of range, w

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/902dd984ab6fa888. Report an issue: GitHub.