mirror of
https://github.com/prometheus/prometheus
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67 lines
2.2 KiB
Go
67 lines
2.2 KiB
Go
package tsdb
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import (
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"testing"
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"github.com/stretchr/testify/require"
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)
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func TestAddJitterToChunkEndTime_ShouldHonorMaxVarianceAndMaxNextAt(t *testing.T) {
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chunkMinTime := int64(10)
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nextAt := int64(95)
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maxNextAt := int64(100)
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variance := 0.2
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// Compute the expected max variance.
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expectedMaxVariance := int64(float64(nextAt-chunkMinTime) * variance)
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for seriesHash := uint64(0); seriesHash < 1000; seriesHash++ {
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actual := addJitterToChunkEndTime(seriesHash, chunkMinTime, nextAt, maxNextAt, variance)
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require.GreaterOrEqual(t, actual, nextAt-(expectedMaxVariance/2))
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require.LessOrEqual(t, actual, maxNextAt)
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}
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}
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func TestAddJitterToChunkEndTime_Distribution(t *testing.T) {
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chunkMinTime := int64(0)
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nextAt := int64(50)
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maxNextAt := int64(100)
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variance := 0.2
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numSeries := uint64(1000)
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// Compute the expected max variance.
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expectedMaxVariance := int64(float64(nextAt-chunkMinTime) * variance)
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// Keep track of the distribution of the applied variance.
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varianceDistribution := map[int64]int64{}
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for seriesHash := uint64(0); seriesHash < numSeries; seriesHash++ {
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actual := addJitterToChunkEndTime(seriesHash, chunkMinTime, nextAt, maxNextAt, variance)
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require.GreaterOrEqual(t, actual, nextAt-(expectedMaxVariance/2))
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require.LessOrEqual(t, actual, nextAt+(expectedMaxVariance/2))
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require.LessOrEqual(t, actual, maxNextAt)
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variance := nextAt - actual
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varianceDistribution[variance]++
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}
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// Ensure a uniform distribution.
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for variance, count := range varianceDistribution {
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require.Equalf(t, int64(numSeries)/expectedMaxVariance, count, "variance = %d", variance)
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}
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}
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func TestAddJitterToChunkEndTime_ShouldNotApplyJitterToTheLastChunkOfTheRange(t *testing.T) {
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// Since the jitter could also be 0, we try it for multiple series.
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for seriesHash := uint64(0); seriesHash < 10; seriesHash++ {
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require.Equal(t, int64(200), addJitterToChunkEndTime(seriesHash, 150, 200, 200, 0.2))
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}
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}
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func TestAddJitterToChunkEndTime_ShouldNotApplyJitterIfDisabled(t *testing.T) {
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// Since the jitter could also be 0, we try it for multiple series.
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for seriesHash := uint64(0); seriesHash < 10; seriesHash++ {
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require.Equal(t, int64(130), addJitterToChunkEndTime(seriesHash, 100, 130, 200, 0))
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}
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}
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