apache/iceberg · error · IllegalArgumentException

Invalid precision: ${precision}

Error message

Invalid precision: ${precision}

What it means

FlinkOrcReaders.decimals selects a decimal reader by precision: <=18 uses a long-backed reader, <=38 a byte-array-backed reader. Any precision above 38 is impossible under Iceberg's decimal spec and throws IllegalArgumentException 'Invalid precision'.

Source

Thrown at flink/v1.20/flink/src/main/java/org/apache/iceberg/flink/data/FlinkOrcReaders.java:69

class FlinkOrcReaders {
  private FlinkOrcReaders() {}

  static OrcValueReader<StringData> strings() {
    return StringReader.INSTANCE;
  }

  static OrcValueReader<Integer> dates() {
    return DateReader.INSTANCE;
  }

  static OrcValueReader<DecimalData> decimals(int precision, int scale) {
    if (precision <= 18) {
      return new Decimal18Reader(precision, scale);
    } else if (precision <= 38) {
      return new Decimal38Reader(precision, scale);
    } else {
      throw new IllegalArgumentException("Invalid precision: " + precision);
    }
  }

  static OrcValueReader<Integer> times() {
    return TimeReader.INSTANCE;
  }

  static OrcValueReader<TimestampData> timestamps() {
    return TimestampReader.INSTANCE;
  }

  static OrcValueReader<TimestampData> timestampTzs() {
    return TimestampTzReader.INSTANCE;
  }

  static <T> OrcValueReader<ArrayData> array(OrcValueReader<T> elementReader) {
    return new ArrayReader<>(elementReader);
  }

View on GitHub (pinned to 86d9c8fc54)

Solutions

1. Fix the schema so decimal precision is between 1 and 38
2. Validate decimal precision at schema creation with TypeUtil/Preconditions before reading/writing
3. Re-check the file's embedded schema validity if it comes from a foreign writer

Example fix

// before
Types.DecimalType.of(45, 5) -> decimals() throws
// after
Types.DecimalType.of(38, 5)

Preconditions.checkArgument(precision >= 1 && precision <= 38, "decimal precision must be 1..38, got %s", precision);

boolean validDecimal(int p) { return p >= 1 && p <= 38; }

try { reader = FlinkOrcReaders.decimals(p, s); } catch (IllegalArgumentException e) { /* fix schema */ throw e; }

When it happens

Trigger: FlinkOrcReaders.decimals(precision, scale) called with precision > 38, e.g. from FlinkOrcReader when a schema declares a decimal beyond ORC/Iceberg limits.

Common situations: Hand-built schemas with decimal(40,x); corrupted or externally produced schema metadata with out-of-spec decimals.

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

• Invalid precision: ${precision}
• Invalid precision: %s
• Invalid precision: %s
• Invalid precision:
• Invalid precision:

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/0db92920213bcd73. Report an issue: GitHub.