metrics/histogram_test.go
Aliaksandr Valialkin d81dd5ec9c Increase value precision in histograms from 5e-3 to 1e-12
Previously values could go into lower bucket because of too coarse precision.

Updates https://github.com/VictoriaMetrics/metrics/issues/8
2020-05-20 02:49:55 +03:00

222 lines
7.8 KiB
Go

package metrics
import (
"bytes"
"fmt"
"math"
"reflect"
"strings"
"testing"
"time"
)
func TestGetBucketIdxAndOffset(t *testing.T) {
f := func(v float64, bucketIdxExpected int, offsetExpected uint) {
t.Helper()
bucketIdx, offset := getBucketIdxAndOffset(v)
if bucketIdx != bucketIdxExpected {
t.Fatalf("unexpected bucketIdx for %g; got %d; want %d", v, bucketIdx, bucketIdxExpected)
}
if offset != offsetExpected {
t.Fatalf("unexpected offset for %g; got %d; want %d", v, offset, offsetExpected)
}
}
const step = 1.0 / decimalMultiplier
const prec = 2 * decimalPrecision
f(0, -1, 0)
f(math.Pow10(e10Min-10), -1, 1)
f(math.Pow10(e10Min-1), -1, 1)
f(3*math.Pow10(e10Min-1), -1, 1)
f(9*math.Pow10(e10Min-1), -1, 1)
f(9.999*math.Pow10(e10Min-1), -1, 1)
f(math.Pow10(e10Min), -1, 1)
f((1+prec)*math.Pow10(e10Min), 0, 0)
f((1+step)*math.Pow10(e10Min), 0, 0)
f((1+step+prec)*math.Pow10(e10Min), 0, 1)
f((1+2*step+prec)*math.Pow10(e10Min), 0, 2)
f((1+3*step+prec)*math.Pow10(e10Min), 0, 3)
f(math.Pow10(e10Min+1), 0, bucketSize-1)
f((1+prec)*math.Pow10(e10Min+1), 1, 0)
f((1+step)*math.Pow10(e10Min+1), 1, 0)
f((1+step+prec)*math.Pow10(e10Min+1), 1, 1)
f(0.1, -e10Min-2, bucketSize-1)
f((1+prec)*0.1, -e10Min-1, 0)
f((1+step)*0.1, -e10Min-1, 0)
f((1+step+prec)*0.1, -e10Min-1, 1)
f((1+(bucketSize-1)*step)*0.1, -e10Min-1, bucketSize-2)
f((1+(bucketSize-1)*step+prec)*0.1, -e10Min-1, bucketSize-1)
f(math.Pow10(e10Max-2), bucketsCount-3, bucketSize-1)
f((1+prec)*math.Pow10(e10Max-2), bucketsCount-2, 0)
f(math.Pow10(e10Max-1), bucketsCount-2, bucketSize-1)
f((1+prec)*math.Pow10(e10Max-1), bucketsCount-1, 0)
f((1+(bucketSize-1)*step)*math.Pow10(e10Max-1), bucketsCount-1, bucketSize-2)
f((1+(bucketSize-1)*step+prec)*math.Pow10(e10Max-1), bucketsCount-1, bucketSize-1)
f(math.Pow10(e10Max), bucketsCount-1, bucketSize-1)
f((1+prec)*math.Pow10(e10Max), -1, 2)
f((1+3*step+prec)*math.Pow10(e10Max), -1, 2)
f(math.Inf(1), -1, 2)
f(999, 11, 17)
f(1000, 11, 17)
f(1001, 12, 0)
f(1002, 12, 0)
f(1003, 12, 0)
}
func TestGetVMRange(t *testing.T) {
f := func(bucketIdx int, offset uint, vmrangeExpected string) {
t.Helper()
vmrange := getVMRange(bucketIdx, offset)
if vmrange != vmrangeExpected {
t.Fatalf("unexpected vmrange for bucketIdx=%d, offset=%d; got %s; want %s", bucketIdx, offset, vmrange, vmrangeExpected)
}
}
const step = 1.0 / decimalMultiplier
f(-1, 0, "0...0")
f(-1, 1, fmt.Sprintf("0...1.0e%d", e10Min))
f(-1, 2, fmt.Sprintf("1.0e%d...+Inf", e10Max))
f(0, 0, fmt.Sprintf("1.0e%d...%.1fe%d", e10Min, 1+step, e10Min))
f(0, 1, fmt.Sprintf("%.1fe%d...%.1fe%d", 1+step, e10Min, 1+2*step, e10Min))
f(0, bucketSize-2, fmt.Sprintf("%.1fe%d...%.1fe%d", 1+(bucketSize-2)*step, e10Min, 1+(bucketSize-1)*step, e10Min))
f(0, bucketSize-1, fmt.Sprintf("%.1fe%d...%.1fe%d", 1+(bucketSize-1)*step, e10Min, 1.0, e10Min+1))
f(-e10Min, 0, fmt.Sprintf("%.1fe%d...%.1fe%d", 1.0, 0, 1+step, 0))
f(-e10Min, 1, fmt.Sprintf("%.1fe%d...%.1fe%d", 1+step, 0, 1+2*step, 0))
f(-e10Min, bucketSize-2, fmt.Sprintf("%.1fe%d...%.1fe%d", 1+(bucketSize-2)*step, 0, 1+(bucketSize-1)*step, 0))
f(-e10Min, bucketSize-1, fmt.Sprintf("%.1fe%d...%.1fe%d", 1+(bucketSize-1)*step, 0, 1.0, 1))
f(bucketsCount-1, bucketSize-2, fmt.Sprintf("%.1fe%d...%.1fe%d", 1+(bucketSize-2)*step, e10Max-1, 1+(bucketSize-1)*step, e10Max-1))
f(bucketsCount-1, bucketSize-1, fmt.Sprintf("%.1fe%d...%.1fe%d", 1+(bucketSize-1)*step, e10Max-1, 1.0, e10Max))
}
func TestHistogramSerial(t *testing.T) {
name := `TestHistogramSerial`
h := NewHistogram(name)
// Verify that the histogram is invisible in the output of WritePrometheus when it has no data.
var bb bytes.Buffer
WritePrometheus(&bb, false)
result := bb.String()
if strings.Contains(result, name) {
t.Fatalf("histogram %s shouldn't be visible in the WritePrometheus output; got\n%s", name, result)
}
// Write data to histogram
for i := 98; i < 218; i++ {
h.Update(float64(i))
}
// Make sure the histogram prints <prefix>_xbucket on marshalTo call
testMarshalTo(t, h, "prefix", "prefix_bucket{vmrange=\"9.5e1...1.0e2\"} 3\nprefix_bucket{vmrange=\"1.0e2...1.5e2\"} 50\nprefix_bucket{vmrange=\"1.5e2...2.0e2\"} 50\nprefix_bucket{vmrange=\"2.0e2...2.5e2\"} 17\nprefix_sum 18900\nprefix_count 120\n")
testMarshalTo(t, h, ` m{foo="bar"}`, "\t m_bucket{foo=\"bar\",vmrange=\"9.5e1...1.0e2\"} 3\n\t m_bucket{foo=\"bar\",vmrange=\"1.0e2...1.5e2\"} 50\n\t m_bucket{foo=\"bar\",vmrange=\"1.5e2...2.0e2\"} 50\n\t m_bucket{foo=\"bar\",vmrange=\"2.0e2...2.5e2\"} 17\n\t m_sum{foo=\"bar\"} 18900\n\t m_count{foo=\"bar\"} 120\n")
// Verify Reset
h.Reset()
bb.Reset()
WritePrometheus(&bb, false)
result = bb.String()
if strings.Contains(result, name) {
t.Fatalf("unexpected histogram %s in the WritePrometheus output; got\n%s", name, result)
}
// Verify supported ranges
for e10 := -100; e10 < 100; e10++ {
for offset := 0; offset < bucketSize; offset++ {
m := 1 + float64(offset+1)/decimalMultiplier
f1 := m * math.Pow10(e10)
h.Update(f1)
f2 := (m + 0.5/decimalMultiplier) * math.Pow10(e10)
h.Update(f2)
f3 := (m + 2*decimalPrecision) * math.Pow10(e10)
h.Update(f3)
}
}
h.UpdateDuration(time.Now().Add(-time.Minute))
// Verify edge cases
h.Update(0)
h.Update(math.Inf(1))
h.Update(math.Inf(-1))
h.Update(math.NaN())
h.Update(-123)
// Make sure the histogram becomes visible in the output of WritePrometheus,
// since now it contains values.
bb.Reset()
WritePrometheus(&bb, false)
result = bb.String()
if !strings.Contains(result, name) {
t.Fatalf("missing histogram %s in the WritePrometheus output; got\n%s", name, result)
}
}
func TestHistogramConcurrent(t *testing.T) {
name := "HistogramConcurrent"
h := NewHistogram(name)
err := testConcurrent(func() error {
for f := 0.6; f < 1.4; f += 0.1 {
h.Update(f)
}
return nil
})
if err != nil {
t.Fatal(err)
}
testMarshalTo(t, h, "prefix", "prefix_bucket{vmrange=\"5.5e-1...6.0e-1\"} 5\nprefix_bucket{vmrange=\"6.5e-1...7.0e-1\"} 5\nprefix_bucket{vmrange=\"7.5e-1...8.0e-1\"} 5\nprefix_bucket{vmrange=\"8.5e-1...9.0e-1\"} 5\nprefix_bucket{vmrange=\"9.5e-1...1.0e0\"} 5\nprefix_bucket{vmrange=\"1.0e0...1.5e0\"} 15\nprefix_sum 38\nprefix_count 40\n")
var labels []string
var counts []uint64
h.VisitNonZeroBuckets(func(label string, count uint64) {
labels = append(labels, label)
counts = append(counts, count)
})
labelsExpected := []string{"5.5e-1...6.0e-1", "6.5e-1...7.0e-1", "7.5e-1...8.0e-1", "8.5e-1...9.0e-1", "9.5e-1...1.0e0", "1.0e0...1.5e0"}
if !reflect.DeepEqual(labels, labelsExpected) {
t.Fatalf("unexpected labels; got %v; want %v", labels, labelsExpected)
}
countsExpected := []uint64{5, 5, 5, 5, 5, 15}
if !reflect.DeepEqual(counts, countsExpected) {
t.Fatalf("unexpected counts; got %v; want %v", counts, countsExpected)
}
}
func TestHistogramWithTags(t *testing.T) {
name := `TestHistogram{tag="foo"}`
h := NewHistogram(name)
h.Update(123)
var bb bytes.Buffer
WritePrometheus(&bb, false)
result := bb.String()
namePrefixWithTag := `TestHistogram_bucket{tag="foo",vmrange="1.0e2...1.5e2"} 1` + "\n"
if !strings.Contains(result, namePrefixWithTag) {
t.Fatalf("missing histogram %s in the WritePrometheus output; got\n%s", namePrefixWithTag, result)
}
}
func TestGetOrCreateHistogramSerial(t *testing.T) {
name := "GetOrCreateHistogramSerial"
if err := testGetOrCreateHistogram(name); err != nil {
t.Fatal(err)
}
}
func TestGetOrCreateHistogramConcurrent(t *testing.T) {
name := "GetOrCreateHistogramConcurrent"
err := testConcurrent(func() error {
return testGetOrCreateHistogram(name)
})
if err != nil {
t.Fatal(err)
}
}
func testGetOrCreateHistogram(name string) error {
h1 := GetOrCreateHistogram(name)
for i := 0; i < 10; i++ {
h2 := GetOrCreateHistogram(name)
if h1 != h2 {
return fmt.Errorf("unexpected histogram returned; got %p; want %p", h2, h1)
}
}
return nil
}