apache/beam · error · IllegalArgumentException

The confidence must be between 0 and 1

Error message

The confidence must be between 0 and 1

What it means

SketchFrequencies.CountMinSketchFn.withAccuracy validates the confidence level; it must lie strictly between 0 and 1 because it represents a probability that the relative error bound holds (the sketch depth derives from ln(1/(1-confidence))). A confidence of 0, 1, or outside this range throws this IllegalArgumentException.

Source

Thrown at sdks/java/extensions/sketching/src/main/java/org/apache/beam/sdk/extensions/sketching/SketchFrequencies.java:387

    }

    /**
     * Returns a new {@link CountMinSketchFn} combiner with new precision accuracy parameters {@code
     * epsilon} and {@code confidence}.
     *
     * <p>Keep in mind that the lower the {@code epsilon} value, the greater the width, and the
     * greater the confidence, the greater the depth.
     *
     * @param epsilon the error relative to the total number of distinct elements
     * @param confidence the confidence in the result to not exceed the relative error
     */
    public CountMinSketchFn<InputT> withAccuracy(double epsilon, double confidence) {
      if (epsilon <= 0D) {
        throw new IllegalArgumentException("The relative error must be positive");
      }

      if (confidence <= 0D || confidence >= 1D) {
        throw new IllegalArgumentException("The confidence must be between 0 and 1");
      }
      return new CountMinSketchFn<>(inputCoder, epsilon, confidence);
    }

    @Override
    public Sketch<InputT> createAccumulator() {
      return Sketch.create(epsilon, confidence);
    }

    @Override
    public Sketch<InputT> addInput(Sketch<InputT> accumulator, InputT element) {
      accumulator.add(element, inputCoder);

      return accumulator;
    }

    @Override
    public Sketch<InputT> mergeAccumulators(Iterable<Sketch<InputT>> accumulators) {

View on GitHub (pinned to 12126d8942)

Solutions

1. Pass a fraction strictly between 0 and 1, e.g. withAccuracy(0.01, 0.999).
2. If your config stores percentages, divide by 100 before calling withAccuracy.
3. Add a pre-check on config values (0 < confidence < 1) before constructing the transform.

Example fix

// before
sketch.withAccuracy(0.01, 99); // throws: 99 is not a fraction
// after
sketch.withAccuracy(0.01, 0.99);

if (!(confidence > 0D && confidence < 1D)) throw new IllegalArgumentException("confidence must be in (0,1), got " + confidence);

try { sketch.withAccuracy(eps, conf); } catch (IllegalArgumentException e) { /* correct units or use defaults */ }

When it happens

Trigger: Calling withAccuracy(epsilon, 1) or withAccuracy(epsilon, 0), or passing a percentage like 99 instead of 0.99, or a config value misparsed as 0.

Common situations: Users passing confidence as a percentage (99, 99.9) rather than a fraction (0.99, 0.999); config/flag defaults of 0 when unset; confusion between fraction and percent conventions.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• The relative error must be positive
• Coder must be deterministic to perform this sketch.${e.getMe
• The accumulators cannot be merged:${e.getMessage()}
• Pipeline update will not be possible because the following t
• One or more ErrorHandlers aren't closed, and this pipeline c

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/362130c1f01d5174. Report an issue: GitHub.