apache/druid · error · java.lang.UnsupportedOperationException

StringAnyBufferAggregator does not support getDouble()

Error message

StringAnyBufferAggregator does not support getDouble()

What it means

Same unsupported-accessor guard as getLong: StringAnyBufferAggregator.getDouble() always throws UnsupportedOperationException because the aggregate value is a UTF-8 string that cannot be read as a double from the buffer. Fires when the query asks for double-typed access on a string ANY aggregate.

Solutions

Cast/parse the resulting string explicitly after aggregation instead of using getDouble().
Aggregate a numeric column directly if a double result is required.
Verify the output type in the query plan matches VARCHAR for the ANY aggregator.

Example fix

// before
double v = bufferAggregator.getDouble(buf, position);
// after
Object v = bufferAggregator.get(buf, position); // string result

Defensive patterns

Strategy: validation

Validate before calling

if (aggFactory instanceof StringAnyAggregatorFactory) { /* read via get(), not getDouble */ }

Type guard

if (factory instanceof StringAnyAggregatorFactory) {
    Object v = bufferAggregator.get(buf, position);
} else {
    double v = bufferAggregator.getDouble(buf, position);
}

Try / catch

try {
    v = bufferAggregator.getDouble(buf, position);
} catch (UnsupportedOperationException e) {
    v = Double.NaN; // or fall back to string get()
}

Prevention

Use a double aggregator when double output is needed
Branch on factory type before numeric access
Parse string results explicitly when numeric values are required

When it happens

Trigger: Calling bufferAggregator.getDouble(buf, position) on a StringAnyAggregatorFactory-created aggregator when numeric output is assumed.

Common situations: Treating a string any-aggregation as numeric in query post-processing; swapping an aggregator type without updating numeric accessors in custom code.

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/31c509a76e6a326a. Report an issue: GitHub.

Appendix: source

Thrown at processing/src/main/java/org/apache/druid/query/aggregation/any/StringAnyBufferAggregator.java:121

    }
  }

  @Override
  public float getFloat(ByteBuffer buf, int position)
  {
    throw new UnsupportedOperationException("StringAnyBufferAggregator does not support getFloat()");
  }

  @Override
  public long getLong(ByteBuffer buf, int position)
  {
    throw new UnsupportedOperationException("StringAnyBufferAggregator does not support getLong()");
  }

  @Override
  public double getDouble(ByteBuffer buf, int position)
  {
    throw new UnsupportedOperationException("StringAnyBufferAggregator does not support getDouble()");
  }

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

View on GitHub (pinned to 9b90983fd2)