vitessio/vitess · error

interval too small

Error message

interval too small

What it means

NewGauges samples gauge values on a background timer, so the sampling interval must be at least 1 second (the -1s sentinel disables snapshotting, mainly for tests). Any smaller positive interval is rejected with a panic because the sampler cannot run reliably below one second.

Source

Thrown at go/stats/gauges.go:45

// Gauges tracks gauge values over time by sampling them at regular intervals.
// Unlike Rates which tracks operation rates, Gauges tracks actual values.
type Gauges struct {
	mu         sync.Mutex
	timeStamps *RingInt64
	history    map[string]*RingInt64    // Historical sampled values
	current    map[string]*atomic.Int64 // Current gauge values
	samples    int
	interval   time.Duration
	ctx        context.Context
	cancel     context.CancelFunc
}

// NewGauges creates a new Gauges object that samples gauge values at regular intervals.
// samples: number of historical samples to keep
// interval: how often to sample the current gauge values
func NewGauges(samples int, interval time.Duration) *Gauges {
	if interval < 1*time.Second && interval != -1*time.Second {
		panic("interval too small")
	}
	ctx, cancel := context.WithCancel(context.Background())
	g := &Gauges{
		timeStamps: NewRingInt64(samples + 1),
		history:    make(map[string]*RingInt64),
		current:    make(map[string]*atomic.Int64),
		samples:    samples + 1,
		interval:   interval,
		ctx:        ctx,
		cancel:     cancel,
	}

	// Start background sampling goroutine
	if interval > 0 {
		go g.track()
	}

	return g

View on GitHub (pinned to 01a25a7d17)

Solutions

1. Pass an interval of at least 1*time.Second to NewGauges.
2. Use -1*time.Second if you intentionally want no snapshotting (test mode).
3. If you need sub-second sampling, this API does not support it — aggregate more frequently elsewhere or change the call site's cadence.

Example fix

// before
g := stats.NewGauges(5, 100*time.Millisecond) // panics: interval too small
// after
g := stats.NewGauges(5, 1*time.Second)

const minInterval = 1 * time.Second
if interval != -1*time.Second && interval < minInterval {
    interval = minInterval // clamp before calling NewGauges
}
g := stats.NewGauges(samples, interval)

When it happens

Trigger: Calling stats.NewGauges(samples, d) where d is 0, or any duration in (0, 1s), e.g. NewGauges(5, 100*time.Millisecond).

Common situations: Copy-pasting an interval from a fast unit test; passing time.Duration(0) as a 'default' without realizing 0 means an unusable sampler; converting from milliseconds to time.Duration incorrectly (e.g. 500 instead of 500*time.Millisecond).

Related errors

• interval too small
• CountersWithMultiLabels: wrong number of values in Add
• CountersWithMultiLabels: wrong number of values in Reset
• GaugesWithMultiLabels: wrong number of values in Set
• You've already registered a function

AI-assisted analysis of vitessio/vitess@01a25a7d17 (2026-09-01). Data as JSON: /api/errors/10151d4785101421. Report an issue: GitHub.