SigNoz/signoz · error

alpha param missing in query

Error message

alpha param missing in query

What it means

The EWMA smoothing functions (EWMA3/EWMA5/EWMA7) require an alpha argument. Validate() returns this when the function has an empty Args slice.

Source

Thrown at pkg/query-service/model/v3/v3.go:1131

			}
			if function.Name == FunctionNameTimeShift {
				if len(function.Args) == 0 {
					return fmt.Errorf("timeShiftBy param missing in query")
				}
				_, ok := function.Args[0].(float64)
				if !ok {
					// if string, attempt to convert to float
					timeShiftBy, err := strconv.ParseFloat(function.Args[0].(string), 64)
					if err != nil {
						return fmt.Errorf("timeShiftBy param should be a number")
					}
					function.Args[0] = timeShiftBy
				}
			} else if function.Name == FunctionNameEWMA3 ||
				function.Name == FunctionNameEWMA5 ||
				function.Name == FunctionNameEWMA7 {
				if len(function.Args) == 0 {
					return fmt.Errorf("alpha param missing in query")
				}
				alpha, ok := function.Args[0].(float64)
				if !ok {
					// if string, attempt to convert to float
					alpha, err := strconv.ParseFloat(function.Args[0].(string), 64)
					if err != nil {
						return fmt.Errorf("alpha param should be a float")
					}
					function.Args[0] = alpha
				}
				if alpha < 0 || alpha > 1 {
					return fmt.Errorf("alpha param should be between 0 and 1")
				}
			} else if function.Name == FunctionNameCutOffMax ||
				function.Name == FunctionNameCutOffMin ||
				function.Name == FunctionNameClampMax ||
				function.Name == FunctionNameClampMin {
				if len(function.Args) == 0 {

View on GitHub (pinned to 5069bf80b0)

Solutions

1. Add an alpha value between 0 and 1, e.g. "args":[0.5]
2. Ensure the client always sends the alpha field for EWMA functions

Example fix

// before
{"name":"EWMA3"}
// after
{"name":"EWMA3","args":[0.5]}

for _, f := range qb.Functions {
  if strings.HasPrefix(string(f.Name), "EWMA") && len(f.Args) == 0 { return errors.New("EWMA requires alpha") }
}

func ewmaHasAlpha(f v3.Function) bool { return !strings.HasPrefix(string(f.Name), "EWMA") || len(f.Args) > 0 }

When it happens

Trigger: "functions":[{"name":"EWMA3"}] with no args, or an args array that is present but empty.

Common situations: UI or API payload construction that omits the smoothing factor; templates with a conditional alpha that evaluates to nothing.

Related errors

• error building clickhouse query: %v
• invalid expression %s: %v
• live tail is only supported for single query
• invalid data type for resource attribute: %s
• unsupported operation, exists and not exists can only be app

AI-assisted analysis of SigNoz/signoz@5069bf80b0 (2026-08-28). Data as JSON: /api/errors/3430307e615a7e14. Report an issue: GitHub.