promql/functions.go
func funcMinOverTime(vals []Value, args Expressions, enh *EvalNodeHelper) Vector {
	return aggrOverTime(vals, enh, func(values []Point) float64 {
		min := values[0].V
		for _, v := range values {
			if v.V < min || math.IsNaN(min) {
				min = v.V
			}
		}
		return min
	})
}
func funcMinOverTime(vals []Value, args Expressions, enh *EvalNodeHelper) Vector {
	return aggrOverTime(vals, enh, func(values []Point) float64 {
		min := values[0].V
		for _, v := range values {
			if v.V < min || math.IsNaN(min) {
				min = v.V
			}
		}
		return min
	})
}
// === min_over_time(Matrix ValueTypeMatrix) Vector ===