apache/druid · error · UnsupportedOperationException

StringAnyAggregator does not support getDouble()

Error message

StringAnyAggregator does not support getDouble()

What it means

StringAnyAggregator's getDouble() throws UnsupportedOperationException with this message; the aggregator holds a string value and refuses to present it as a double. Typed accessors on this class exist solely to fail fast on type misuse instead of producing misleading numeric results.

Solutions

Use getString() and a CastPostAggregator to DOUBLE before any numeric post-aggregation
Aggregate the underlying numeric column with doubleAny or another numeric aggregator instead of the string column
Update result-consuming code to check the aggregator's type (string vs numeric) before choosing an accessor
Re-model the datasource so numeric data is stored with a numeric type

Example fix

// before
row.getDouble("stringAnyMetric")
// after
String s = row.getString("stringAnyMetric");
double d = s == null ? Double.NaN : Double.parseDouble(s); // or CastPostAggregator to DOUBLE

Defensive patterns

Strategy: type-guard

Validate before calling

if (aggregator instanceof StringAnyAggregator) {
  throw new ISE("stringAny metric cannot be read as double");
}

Type guard

boolean supportsDouble(Aggregator a) { return !(a instanceof StringAnyAggregator); }

Try / catch

try {
  double d = aggregator.getDouble();
} catch (UnsupportedOperationException e) {
  String s = aggregator.getString();
  double d = s == null ? Double.NaN : Double.parseDouble(s);
}

Prevention

Use getString() for stringAny results; reserve getDouble() for numeric aggregators
Add CastPostAggregator (to DOUBLE) between string metrics and numeric post-aggregators
Store numeric data with numeric column types to avoid string aggregation paths
Tools iterating all aggregators must check types before calling typed getters

When it happens

Trigger: Calling getDouble() on a stringAny aggregator's result — e.g. a doubleSum/arithmetic post-aggregator, an expression referencing the metric numerically, or generic result-row code that assumes double-typed metrics.

Common situations: Native queries with numeric post-aggregators bound to stringAny metrics; dashboards/tools that iterate aggregators and call getDouble() unconditionally; SQL plans where a VARCHAR any-aggregation is consumed by numeric functions.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of apache/druid@9b90983fd2 (2026-09-07). Data as JSON: /api/errors/18aa29dc6519fdc9. Report an issue: GitHub.

Appendix: source

Thrown at processing/src/main/java/org/apache/druid/query/aggregation/any/StringAnyAggregator.java:98

    return foundValue;
  }

  @Override
  public float getFloat()
  {
    throw new UnsupportedOperationException("StringAnyAggregator does not support getFloat()");
  }

  @Override
  public long getLong()
  {
    throw new UnsupportedOperationException("StringAnyAggregator does not support getLong()");
  }

  @Override
  public double getDouble()
  {
    throw new UnsupportedOperationException("StringAnyAggregator does not support getDouble()");
  }

  @Override
  public void close()
  {
    // no-op
  }
}

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