app/vmselect/promql: remove spikes from increase() and delta() results on time series with spare irregular data points

Do not take into account spare data point value if the next point will is located too far from the current point.

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/894
This commit is contained in:
Aliaksandr Valialkin 2020-11-13 15:21:51 +02:00
parent 1f19c167a4
commit d9d01f976b
2 changed files with 38 additions and 17 deletions

View File

@ -338,9 +338,12 @@ type rollupFuncArg struct {
// Timestamps for values.
timestamps []int64
// Actual value preceeding values without restrictions on staleness interval.
// Real value preceeding values without restrictions on staleness interval.
realPrevValue float64
// Real value which goes after values.
realNextValue float64
// Current timestamp for rollup evaluation.
currTimestamp int64
@ -558,6 +561,11 @@ func (rc *rollupConfig) doInternal(dstValues []float64, tsm *timeseriesMap, valu
} else {
rfa.realPrevValue = nan
}
if j < len(values) {
rfa.realNextValue = values[j]
} else {
rfa.realNextValue = nan
}
rfa.currTimestamp = tEnd
value := rc.Func(rfa)
rfa.idx++
@ -1282,6 +1290,8 @@ func rollupDelta(rfa *rollupFuncArg) float64 {
d := float64(10)
if len(values) > 1 {
d = values[1] - values[0]
} else if !math.IsNaN(rfa.realNextValue) {
d = rfa.realNextValue - values[0]
}
if math.Abs(values[0]) < 10*(math.Abs(d)+1) {
prevValue = 0

View File

@ -1103,12 +1103,13 @@ func testRowsEqual(t *testing.T, values []float64, timestamps []int64, valuesExp
}
func TestRollupDelta(t *testing.T) {
f := func(prevValue, realPrevValue float64, values []float64, resultExpected float64) {
f := func(prevValue, realPrevValue, realNextValue float64, values []float64, resultExpected float64) {
t.Helper()
rfa := &rollupFuncArg{
prevValue: prevValue,
values: values,
realPrevValue: realPrevValue,
realNextValue: realNextValue,
}
result := rollupDelta(rfa)
if math.IsNaN(result) {
@ -1121,26 +1122,36 @@ func TestRollupDelta(t *testing.T) {
t.Fatalf("unexpected result; got %v; want %v", result, resultExpected)
}
}
f(nan, nan, nil, nan)
f(nan, nan, nan, nil, nan)
// Small initial value
f(nan, nan, []float64{1}, 1)
f(nan, nan, []float64{10}, 10)
f(nan, nan, []float64{100}, 100)
f(nan, nan, []float64{1, 2, 3}, 3)
f(1, nan, []float64{1, 2, 3}, 2)
f(nan, nan, []float64{5, 6, 8}, 8)
f(2, nan, []float64{5, 6, 8}, 6)
f(nan, nan, nan, []float64{1}, 1)
f(nan, nan, nan, []float64{10}, 10)
f(nan, nan, nan, []float64{100}, 100)
f(nan, nan, nan, []float64{1, 2, 3}, 3)
f(1, nan, nan, []float64{1, 2, 3}, 2)
f(nan, nan, nan, []float64{5, 6, 8}, 8)
f(2, nan, nan, []float64{5, 6, 8}, 6)
// Too big initial value must be skipped.
f(nan, nan, []float64{1000}, 0)
f(nan, nan, []float64{1000, 1001, 1002}, 2)
f(nan, nan, nan, []float64{1000}, 0)
f(nan, nan, nan, []float64{1000, 1001, 1002}, 2)
// Delta calculations against non-nan realPrevValue
f(nan, 900, []float64{1000}, 100)
f(nan, 900, []float64{1000, 1001, 1002}, 102)
// Non-nan realPrevValue
f(nan, 900, nan, []float64{1000}, 100)
f(nan, 1000, nan, []float64{1000}, 0)
f(nan, 1100, nan, []float64{1000}, -100)
f(nan, 900, nan, []float64{1000, 1001, 1002}, 102)
// Small delta between realNextValue and values
f(nan, nan, 990, []float64{1000}, 0)
f(nan, nan, 1005, []float64{1000}, 0)
// Big delta between relaNextValue and values
f(nan, nan, 800, []float64{1000}, 1000)
f(nan, nan, 1300, []float64{1000}, 1000)
// Empty values
f(1, nan, nil, 0)
f(100, nan, nil, 0)
f(1, nan, nan, nil, 0)
f(100, nan, nan, nil, 0)
}