dgraph-io/dgraph · error

Value for 'distance_threshold' must be non-negative, got: %v

Error message

Value for 'distance_threshold' must be non-negative, got: %v

What it means

A parsed 'distance_threshold' must be non-negative because it filters vector-search results by distance, and negative distances do not exist. When the value parses as a float but is < 0, this error is returned.

Source

Thrown at worker/task.go:2813

		v = strings.Trim(v, "\"'")
		switch k {
		case "ef":
			n, perr := strconv.ParseInt(v, 10, 32)
			if perr != nil {
				return errors.Errorf("Invalid value for 'ef' in similar_to: %q", v)
			}
			if n <= 0 {
				return errors.Errorf("Value for 'ef' must be positive, got: %d", n)
			}
			fc.vsEfOverride = int(n)
		case "distance_threshold":
			f, perr := strconv.ParseFloat(v, 64)
			if perr != nil {
				return errors.Errorf("Invalid value for 'distance_threshold' in similar_to: %q", v)
			}
			if f < 0 {
				return errors.Errorf("Value for 'distance_threshold' must be non-negative, got: %v", f)
			}
			fc.vsDistanceThreshold = new(float64)
			*fc.vsDistanceThreshold = f
		default:
			return errors.Errorf("Unknown option in similar_to: %q", k)
		}
	}
	return nil
}

View on GitHub (pinned to 759e242be6)

Solutions

  1. Set a non-negative threshold, e.g. 'distance_threshold: 0.5'; 0 is allowed.
  2. Omit the option entirely instead of using a negative sentinel for 'unset'.
  3. Clamp the computed value to >= 0 in your query builder.

Example fix

// before
opts += "; distance_threshold: " + fmt.Sprintf("%v", thr) // thr = -1 sentinel
// after
if thr >= 0 { opts += "; distance_threshold: " + fmt.Sprintf("%v", thr) }
Defensive patterns

Strategy: validation

Validate before calling

if thr < 0 {
    return fmt.Errorf("distance_threshold must be >= 0, got %v", thr)
}
opts := "; distance_threshold: " + strconv.FormatFloat(thr, 'f', -1, 64)

Try / catch

if err := runQuery(ctx); err != nil && strings.Contains(err.Error(), "'distance_threshold' must be non-negative") {
    return retryWithoutThreshold(ctx)
}

Prevention

When it happens

Trigger: similar_to option string like 'distance_threshold: -0.5' or 'distance_threshold: -1'. The float parses fine but fails the f < 0 check.

Common situations: Sign errors when computing the threshold from a formula; users confusing threshold with a 'score' where lower is better and attempting negative values; template defaults of -1 used as sentinel 'unset' that get serialized.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

AI-assisted analysis of dgraph-io/dgraph@759e242be6 (2026-09-01). Data as JSON: /api/errors/b9dc158af4d71ca4. Report an issue: GitHub.