cachebench: observation line %d: empty or duplicate request_

Error message

cachebench: observation line %d: empty or duplicate request_id

What it means

Error "cachebench: observation line %d: empty or duplicate request_id" thrown in JuliusBrussee/caveman.

Source

Thrown at cacheengine/cachebench/observed.go:132

		}
		if !validUniqueJSONObject(raw) {
			return nil, fmt.Errorf("cachebench: observation line %d: duplicate or invalid JSON", line)
		}
		decoder := json.NewDecoder(bytes.NewReader(raw))
		decoder.DisallowUnknownFields()
		var record ObservationRecord
		if err := decoder.Decode(&record); err != nil {
			return nil, fmt.Errorf("cachebench: observation line %d: %w", line, err)
		}
		var trailing any
		if err := decoder.Decode(&trailing); err != io.EOF {
			return nil, fmt.Errorf("cachebench: observation line %d: trailing JSON", line)
		}
		if record.Schema != ObservationSchema {
			return nil, fmt.Errorf("cachebench: observation line %d: schema %q", line, record.Schema)
		}
		if strings.TrimSpace(record.RequestID) == "" || seen[record.RequestID] {
			return nil, fmt.Errorf("cachebench: observation line %d: empty or duplicate request_id", line)
		}
		seen[record.RequestID] = true
		record.Usage = append(json.RawMessage(nil), record.Usage...)
		records = append(records, record)
	}
	if err := scanner.Err(); err != nil {
		return nil, fmt.Errorf("cachebench: read observations: %w", err)
	}
	if len(records) == 0 {
		return nil, errors.New("cachebench: no observation records")
	}
	if err := validateObservationRecords(records); err != nil {
		return nil, err
	}
	return records, nil
}

// EvaluateObserved evaluates supplied observations without completeness claim.

View on GitHub (pinned to 27d5a3981a)

Solutions

Give each observation a non-empty, unique request_id.

When it happens

Trigger: Thrown at cacheengine/cachebench/observed.go:132 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of JuliusBrussee/caveman@27d5a3981a (2026-08-15). Data as JSON: /api/errors/1fb2147453f52156. Report an issue: GitHub.