vitessio/vitess · error

missing value for 'rate'

Error message

missing value for 'rate'

What it means

servenv parses the --pprof-profile-flag value as comma-separated key=value pairs. When a segment is 'rate' with no '=' (SplitN yields one field), parseProfileFlag cannot determine the CPU profile rate and returns this error, aborting pprof initialization.

Source

Thrown at go/vt/servenv/pprof.go:107

		p.rate = 1
	case "trace":
		p.mode = profileTrace
	case "threads":
		p.mode = profileThreads
	case "goroutine":
		p.mode = profileGoroutine
	default:
		return nil, fmt.Errorf("unknown profile mode: %q", pf[0])
	}

	for _, kv := range pf[1:] {
		var err error
		fields := strings.SplitN(kv, "=", 2)

		switch fields[0] {
		case "rate":
			if len(fields) == 1 {
				return nil, errors.New("missing value for 'rate'")
			}
			p.rate, err = strconv.Atoi(fields[1])
			if err != nil {
				return nil, fmt.Errorf("invalid profile rate %q: %v", fields[1], err)
			}

		case "path":
			if len(fields) == 1 {
				return nil, errors.New("missing value for 'path'")
			}
			p.path = fields[1]

		case "quiet":
			if len(fields) == 1 {
				p.quiet = true
				continue
			}

View on GitHub (pinned to 01a25a7d17)

Solutions

1. Set --pprof-profile-flag=rate=<int> (e.g. rate=1000)
2. Remove the bare 'rate' token if you don't need a custom rate
3. Check the flag value with ps/proc args to confirm what the process actually received

Example fix

// before
--pprof-profile-flag=rate
// after
--pprof-profile-flag=rate=1000

for _, kv := range strings.Split(profileFlag, ",") {
    if strings.HasPrefix(kv, "rate") && !strings.Contains(kv, "=") {
        return errors.New("pprof flag 'rate' needs a value: rate=<int>")
    }
}

When it happens

Trigger: Starting a server with --pprof-profile-flag=rate (or 'rate,quiet=...') — i.e. 'rate' present without '=value'.

Common situations: Typo'd flags like --pprof-profile-flag=rate instead of rate=100; shell scripts that strip the value during templating.

Understand the failure class

Background: "unknown output mode", "invalid value for flag", "expects true/false": fixing invalid flag value errors in CLI tools — this error's family across 24 libraries.

Related errors

• missing value for 'path'
• error parsing %s: %w
• unsupported profile mode
• --batch-size requires 'direct' ddl_strategy
• --batch-size conflicts with --uuid-list. Batching does not s

AI-assisted analysis of vitessio/vitess@01a25a7d17 (2026-09-01). Data as JSON: /api/errors/4aa050ee460e7dcb. Report an issue: GitHub.