What causes "Aggregators must not contain null elements" in redis/jedis?

Replace null entries with valid AggregationType constants (MIN, MAX, AVG, SUM, COUNT, etc.).

redis/jedis · error · IllegalArgumentException

Aggregators must not contain null elements

Error message

Aggregators must not contain null elements

What it means

TSRangeParams.aggregation(AggregationType[] aggregators, long bucketDuration) rejects null elements inside the aggregator array. A null AggregationType cannot be encoded into the AGGREGATION argument of TS.RANGE, so the library throws IllegalArgumentException during parameter building.

Solutions

Replace null entries with valid AggregationType constants (MIN, MAX, AVG, SUM, COUNT, etc.).
Fail at parse time when a configured aggregation name cannot be resolved to an AggregationType, instead of storing null.
Filter with Objects::nonNull only if trailing nulls are semantically unwanted — but prefer fixing the producer so no nulls are created.

Example fix

// before
AggregationType[] aggs = new AggregationType[2];
aggs[0] = AggregationType.SUM;
params.aggregation(aggs, 10000); // aggs[1] == null -> throws
// after
AggregationType[] aggs = new AggregationType[]{AggregationType.SUM, AggregationType.AVG};
params.aggregation(aggs, 10000);

Defensive patterns

Strategy: validation

Validate before calling

if (Arrays.stream(aggs).anyMatch(Objects::isNull)) {
  throw new IllegalStateException("null aggregator in config");
}
params.aggregation(aggs, bucketMs);

Type guard

static AggregationType[] nonNullAggs(AggregationType[] in) { return Arrays.stream(in).filter(Objects::nonNull).toArray(AggregationType[]::new); }

Try / catch

try { params.aggregation(aggs, bucketMs); } catch (IllegalArgumentException e) { throw new ConfigurationException("null aggregator", e); }

Prevention

Fail at config parse time on unknown aggregation names
Initialize arrays with all values, or use List.of(...)
Run a null-scan on builder inputs in tests

When it happens

Trigger: Calling TSRangeParams.aggregation(new AggregationType[]{AggregationType.MIN, null}, bucketDuration), or arrays produced by AggregationType[n] pre-sizing with unfilled slots.

Common situations: Mapping user-supplied aggregation names via a lookup that returns null for unknown values; deserialized configuration containing incomplete aggregator lists.

Related errors

AI-assisted analysis of redis/jedis@6dac31d4c2 (2026-09-08). Data as JSON: /api/errors/482845f1024cba59. Report an issue: GitHub.

Appendix: source

Thrown at src/main/java/redis/clients/jedis/timeseries/TSRangeParams.java:139

  /**
   * Specifies multiple aggregators to be applied in a single {@code TS.RANGE} / {@code TS.REVRANGE} call. Aggregators are
   * sent on the wire in the given order and the response values appear in the same order in {@link TSElement#getValues()}.
   * Single-element arrays are accepted and behave like {@link #aggregation(AggregationType, long)}.
   *
   * @param aggregators ordered, non-empty list of aggregators
   * @param bucketDuration aggregation bucket duration in milliseconds
   * @return this
   * @throws IllegalArgumentException if {@code aggregators} is empty
   */
  public TSRangeParams aggregation(AggregationType[] aggregators, long bucketDuration) {
    if (aggregators != null) {
      if (aggregators.length == 0) {
        throw new IllegalArgumentException("At least one aggregator is required");
      }
      for (AggregationType a : aggregators) {
        if (a == null) {
          throw new IllegalArgumentException("Aggregators must not contain null elements");
        }
      }
      this.aggregators = aggregators;
      this.bucketDuration = bucketDuration;
    } else {
      this.aggregators = null;
      this.bucketDuration = 0;
    }

    return this;
  }

  /**
   * This requires AGGREGATION.
   */
  public TSRangeParams bucketTimestamp(String bucketTimestamp) {
    this.bucketTimestamp = encode(bucketTimestamp);
    return this;

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