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5f366e9b62
This adds negative buckets and access of float histograms to TestHistogramChunkSameBuckets and TestHistogramChunkBucketChanges. It also exercises a specific pattern of reusing an iterator (one where no access has happened). This exposes two bugs (where entries for positive buckets where used where the corresponding entries for negative buckets should have been used). One was fixed in #11627 (not merged), which triggered the work in this commit. This commit fixes both issues, so #11627 can be closed. It also simplifies the code in the histogramIterator.Next method that aims to recycle existing slice capacity. Furthermore, this is on top of the release-2.40 branch because we should probably cut a bugfix release for this. Signed-off-by: beorn7 <beorn@grafana.com>
510 lines
15 KiB
Go
510 lines
15 KiB
Go
// Copyright 2021 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package chunkenc
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import (
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"testing"
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"github.com/stretchr/testify/require"
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"github.com/prometheus/prometheus/model/histogram"
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)
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type result struct {
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t int64
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h *histogram.Histogram
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fh *histogram.FloatHistogram
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}
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func TestHistogramChunkSameBuckets(t *testing.T) {
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c := NewHistogramChunk()
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var exp []result
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// Create fresh appender and add the first histogram.
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app, err := c.Appender()
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require.NoError(t, err)
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require.Equal(t, 0, c.NumSamples())
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ts := int64(1234567890)
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h := &histogram.Histogram{
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Count: 15,
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ZeroCount: 2,
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Sum: 18.4,
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ZeroThreshold: 1e-100,
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Schema: 1,
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PositiveSpans: []histogram.Span{
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{Offset: 0, Length: 2},
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{Offset: 1, Length: 2},
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},
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PositiveBuckets: []int64{1, 1, -1, 0}, // counts: 1, 2, 1, 1 (total 5)
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NegativeSpans: []histogram.Span{
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{Offset: 1, Length: 1},
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{Offset: 2, Length: 3},
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},
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NegativeBuckets: []int64{2, 1, -1, -1}, // counts: 2, 3, 2, 1 (total 8)
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}
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app.AppendHistogram(ts, h)
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exp = append(exp, result{t: ts, h: h, fh: h.ToFloat()})
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require.Equal(t, 1, c.NumSamples())
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// Add an updated histogram.
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ts += 16
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h = h.Copy()
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h.Count = 32
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h.ZeroCount++
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h.Sum = 24.4
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h.PositiveBuckets = []int64{5, -2, 1, -2} // counts: 5, 3, 4, 2 (total 14)
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h.NegativeBuckets = []int64{4, -1, 1, -1} // counts: 4, 3, 4, 4 (total 15)
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app.AppendHistogram(ts, h)
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exp = append(exp, result{t: ts, h: h, fh: h.ToFloat()})
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require.Equal(t, 2, c.NumSamples())
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// Add update with new appender.
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app, err = c.Appender()
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require.NoError(t, err)
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ts += 14
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h = h.Copy()
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h.Count = 54
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h.ZeroCount += 2
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h.Sum = 24.4
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h.PositiveBuckets = []int64{6, 1, -3, 6} // counts: 6, 7, 4, 10 (total 27)
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h.NegativeBuckets = []int64{5, 1, -2, 3} // counts: 5, 6, 4, 7 (total 22)
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app.AppendHistogram(ts, h)
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exp = append(exp, result{t: ts, h: h, fh: h.ToFloat()})
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require.Equal(t, 3, c.NumSamples())
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// 1. Expand iterator in simple case.
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it := c.Iterator(nil)
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require.NoError(t, it.Err())
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var act []result
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for it.Next() == ValHistogram {
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ts, h := it.AtHistogram()
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fts, fh := it.AtFloatHistogram()
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require.Equal(t, ts, fts)
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act = append(act, result{t: ts, h: h, fh: fh})
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}
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require.NoError(t, it.Err())
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require.Equal(t, exp, act)
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// 2. Expand second iterator while reusing first one.
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it2 := c.Iterator(it)
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var act2 []result
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for it2.Next() == ValHistogram {
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ts, h := it2.AtHistogram()
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fts, fh := it2.AtFloatHistogram()
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require.Equal(t, ts, fts)
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act2 = append(act2, result{t: ts, h: h, fh: fh})
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}
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require.NoError(t, it2.Err())
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require.Equal(t, exp, act2)
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// 3. Now recycle an iterator that was never used to access anything.
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itX := c.Iterator(nil)
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for itX.Next() == ValHistogram {
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// Just iterate through without accessing anything.
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}
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it3 := c.iterator(itX)
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var act3 []result
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for it3.Next() == ValHistogram {
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ts, h := it3.AtHistogram()
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fts, fh := it3.AtFloatHistogram()
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require.Equal(t, ts, fts)
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act3 = append(act3, result{t: ts, h: h, fh: fh})
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}
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require.NoError(t, it3.Err())
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require.Equal(t, exp, act3)
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// 4. Test iterator Seek.
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mid := len(exp) / 2
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it4 := c.Iterator(nil)
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var act4 []result
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require.Equal(t, ValHistogram, it4.Seek(exp[mid].t))
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// Below ones should not matter.
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require.Equal(t, ValHistogram, it4.Seek(exp[mid].t))
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require.Equal(t, ValHistogram, it4.Seek(exp[mid].t))
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ts, h = it4.AtHistogram()
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fts, fh := it4.AtFloatHistogram()
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require.Equal(t, ts, fts)
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act4 = append(act4, result{t: ts, h: h, fh: fh})
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for it4.Next() == ValHistogram {
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ts, h := it4.AtHistogram()
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fts, fh := it4.AtFloatHistogram()
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require.Equal(t, ts, fts)
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act4 = append(act4, result{t: ts, h: h, fh: fh})
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}
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require.NoError(t, it4.Err())
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require.Equal(t, exp[mid:], act4)
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require.Equal(t, ValNone, it4.Seek(exp[len(exp)-1].t+1))
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}
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// Mimics the scenario described for compareSpans().
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func TestHistogramChunkBucketChanges(t *testing.T) {
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c := Chunk(NewHistogramChunk())
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// Create fresh appender and add the first histogram.
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app, err := c.Appender()
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require.NoError(t, err)
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require.Equal(t, 0, c.NumSamples())
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ts1 := int64(1234567890)
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h1 := &histogram.Histogram{
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Count: 27,
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ZeroCount: 2,
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Sum: 18.4,
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ZeroThreshold: 1e-125,
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Schema: 1,
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PositiveSpans: []histogram.Span{
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{Offset: 0, Length: 2},
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{Offset: 2, Length: 1},
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{Offset: 3, Length: 2},
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{Offset: 3, Length: 1},
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{Offset: 1, Length: 1},
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},
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PositiveBuckets: []int64{6, -3, 0, -1, 2, 1, -4}, // counts: 6, 3, 3, 2, 4, 5, 1 (total 24)
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NegativeSpans: []histogram.Span{{Offset: 1, Length: 1}},
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NegativeBuckets: []int64{1},
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}
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app.AppendHistogram(ts1, h1)
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require.Equal(t, 1, c.NumSamples())
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// Add a new histogram that has expanded buckets.
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ts2 := ts1 + 16
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h2 := h1.Copy()
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h2.PositiveSpans = []histogram.Span{
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{Offset: 0, Length: 3},
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{Offset: 1, Length: 1},
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{Offset: 1, Length: 4},
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{Offset: 3, Length: 3},
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}
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h2.NegativeSpans = []histogram.Span{{Offset: 0, Length: 2}}
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h2.Count = 35
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h2.ZeroCount++
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h2.Sum = 30
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// Existing histogram should get values converted from the above to:
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// 6 3 0 3 0 0 2 4 5 0 1 (previous values with some new empty buckets in between)
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// so the new histogram should have new counts >= these per-bucket counts, e.g.:
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h2.PositiveBuckets = []int64{7, -2, -4, 2, -2, -1, 2, 3, 0, -5, 1} // 7 5 1 3 1 0 2 5 5 0 1 (total 30)
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// Existing histogram should get values converted from the above to:
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// 0 1 (previous values with some new empty buckets in between)
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// so the new histogram should have new counts >= these per-bucket counts, e.g.:
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h2.NegativeBuckets = []int64{2, -1} // 2 1 (total 3)
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// This is how span changes will be handled.
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hApp, _ := app.(*HistogramAppender)
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posInterjections, negInterjections, ok, cr := hApp.Appendable(h2)
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require.Greater(t, len(posInterjections), 0)
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require.Greater(t, len(negInterjections), 0)
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require.True(t, ok) // Only new buckets came in.
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require.False(t, cr)
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c, app = hApp.Recode(posInterjections, negInterjections, h2.PositiveSpans, h2.NegativeSpans)
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app.AppendHistogram(ts2, h2)
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require.Equal(t, 2, c.NumSamples())
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// Because the 2nd histogram has expanded buckets, we should expect all
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// histograms (in particular the first) to come back using the new spans
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// metadata as well as the expanded buckets.
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h1.PositiveSpans = h2.PositiveSpans
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h1.PositiveBuckets = []int64{6, -3, -3, 3, -3, 0, 2, 2, 1, -5, 1}
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h1.NegativeSpans = h2.NegativeSpans
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h1.NegativeBuckets = []int64{0, 1}
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exp := []result{
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{t: ts1, h: h1, fh: h1.ToFloat()},
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{t: ts2, h: h2, fh: h2.ToFloat()},
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}
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it := c.Iterator(nil)
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var act []result
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for it.Next() == ValHistogram {
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ts, h := it.AtHistogram()
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fts, fh := it.AtFloatHistogram()
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require.Equal(t, ts, fts)
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act = append(act, result{t: ts, h: h, fh: fh})
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}
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require.NoError(t, it.Err())
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require.Equal(t, exp, act)
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}
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func TestHistogramChunkAppendable(t *testing.T) {
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c := Chunk(NewHistogramChunk())
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// Create fresh appender and add the first histogram.
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app, err := c.Appender()
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require.NoError(t, err)
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require.Equal(t, 0, c.NumSamples())
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ts := int64(1234567890)
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h1 := &histogram.Histogram{
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Count: 5,
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ZeroCount: 2,
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Sum: 18.4,
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ZeroThreshold: 1e-125,
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Schema: 1,
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PositiveSpans: []histogram.Span{
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{Offset: 0, Length: 2},
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{Offset: 2, Length: 1},
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{Offset: 3, Length: 2},
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{Offset: 3, Length: 1},
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{Offset: 1, Length: 1},
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},
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PositiveBuckets: []int64{6, -3, 0, -1, 2, 1, -4}, // counts: 6, 3, 3, 2, 4, 5, 1 (total 24)
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}
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app.AppendHistogram(ts, h1)
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require.Equal(t, 1, c.NumSamples())
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{ // New histogram that has more buckets.
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h2 := h1
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h2.PositiveSpans = []histogram.Span{
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{Offset: 0, Length: 3},
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{Offset: 1, Length: 1},
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{Offset: 1, Length: 4},
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{Offset: 3, Length: 3},
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}
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h2.Count += 9
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h2.ZeroCount++
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h2.Sum = 30
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// Existing histogram should get values converted from the above to:
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// 6 3 0 3 0 0 2 4 5 0 1 (previous values with some new empty buckets in between)
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// so the new histogram should have new counts >= these per-bucket counts, e.g.:
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h2.PositiveBuckets = []int64{7, -2, -4, 2, -2, -1, 2, 3, 0, -5, 1} // 7 5 1 3 1 0 2 5 5 0 1 (total 30)
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hApp, _ := app.(*HistogramAppender)
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posInterjections, negInterjections, ok, cr := hApp.Appendable(h2)
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require.Greater(t, len(posInterjections), 0)
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require.Equal(t, 0, len(negInterjections))
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require.True(t, ok) // Only new buckets came in.
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require.False(t, cr)
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}
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{ // New histogram that has a bucket missing.
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h2 := h1
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h2.PositiveSpans = []histogram.Span{
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{Offset: 0, Length: 2},
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{Offset: 5, Length: 2},
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{Offset: 3, Length: 1},
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{Offset: 1, Length: 1},
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}
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h2.Sum = 21
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h2.PositiveBuckets = []int64{6, -3, -1, 2, 1, -4} // counts: 6, 3, 2, 4, 5, 1 (total 21)
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hApp, _ := app.(*HistogramAppender)
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posInterjections, negInterjections, ok, cr := hApp.Appendable(h2)
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require.Equal(t, 0, len(posInterjections))
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require.Equal(t, 0, len(negInterjections))
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require.False(t, ok) // Need to cut a new chunk.
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require.True(t, cr)
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}
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{ // New histogram that has a counter reset while buckets are same.
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h2 := h1
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h2.Sum = 23
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h2.PositiveBuckets = []int64{6, -4, 1, -1, 2, 1, -4} // counts: 6, 2, 3, 2, 4, 5, 1 (total 23)
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hApp, _ := app.(*HistogramAppender)
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posInterjections, negInterjections, ok, cr := hApp.Appendable(h2)
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require.Equal(t, 0, len(posInterjections))
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require.Equal(t, 0, len(negInterjections))
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require.False(t, ok) // Need to cut a new chunk.
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require.True(t, cr)
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}
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{ // New histogram that has a counter reset while new buckets were added.
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h2 := h1
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h2.PositiveSpans = []histogram.Span{
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{Offset: 0, Length: 3},
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{Offset: 1, Length: 1},
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{Offset: 1, Length: 4},
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{Offset: 3, Length: 3},
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}
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h2.Sum = 29
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// Existing histogram should get values converted from the above to:
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// 6 3 0 3 0 0 2 4 5 0 1 (previous values with some new empty buckets in between)
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// so the new histogram should have new counts >= these per-bucket counts, e.g.:
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h2.PositiveBuckets = []int64{7, -2, -4, 2, -2, -1, 2, 3, 0, -5, 0} // 7 5 1 3 1 0 2 5 5 0 0 (total 29)
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hApp, _ := app.(*HistogramAppender)
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posInterjections, negInterjections, ok, cr := hApp.Appendable(h2)
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require.Equal(t, 0, len(posInterjections))
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require.Equal(t, 0, len(negInterjections))
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require.False(t, ok) // Need to cut a new chunk.
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require.True(t, cr)
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}
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{
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// New histogram that has a counter reset while new buckets were
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// added before the first bucket and reset on first bucket. (to
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// catch the edge case where the new bucket should be forwarded
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// ahead until first old bucket at start)
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h2 := h1
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h2.PositiveSpans = []histogram.Span{
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{Offset: -3, Length: 2},
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{Offset: 1, Length: 2},
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{Offset: 2, Length: 1},
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{Offset: 3, Length: 2},
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{Offset: 3, Length: 1},
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{Offset: 1, Length: 1},
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}
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h2.Sum = 26
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// Existing histogram should get values converted from the above to:
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// 0, 0, 6, 3, 3, 2, 4, 5, 1
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// so the new histogram should have new counts >= these per-bucket counts, e.g.:
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h2.PositiveBuckets = []int64{1, 1, 3, -2, 0, -1, 2, 1, -4} // counts: 1, 2, 5, 3, 3, 2, 4, 5, 1 (total 26)
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hApp, _ := app.(*HistogramAppender)
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posInterjections, negInterjections, ok, cr := hApp.Appendable(h2)
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require.Equal(t, 0, len(posInterjections))
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require.Equal(t, 0, len(negInterjections))
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require.False(t, ok) // Need to cut a new chunk.
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require.True(t, cr)
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}
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}
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func TestAtFloatHistogram(t *testing.T) {
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input := []histogram.Histogram{
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{
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Schema: 0,
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Count: 21,
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Sum: 1234.5,
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ZeroThreshold: 0.001,
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ZeroCount: 4,
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PositiveSpans: []histogram.Span{
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{Offset: 0, Length: 4},
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{Offset: 0, Length: 0},
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{Offset: 0, Length: 3},
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},
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PositiveBuckets: []int64{1, 1, -1, 0, 0, 0, 0},
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NegativeSpans: []histogram.Span{
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{Offset: 1, Length: 4},
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{Offset: 2, Length: 0},
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{Offset: 2, Length: 3},
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},
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NegativeBuckets: []int64{1, 1, -1, 1, 0, 0, 0},
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},
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{
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Schema: 0,
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Count: 36,
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Sum: 2345.6,
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ZeroThreshold: 0.001,
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ZeroCount: 5,
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PositiveSpans: []histogram.Span{
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{Offset: 0, Length: 4},
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{Offset: 0, Length: 0},
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{Offset: 0, Length: 3},
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},
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PositiveBuckets: []int64{1, 2, -2, 1, -1, 0, 0},
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NegativeSpans: []histogram.Span{
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{Offset: 1, Length: 4},
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{Offset: 2, Length: 0},
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{Offset: 2, Length: 3},
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},
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NegativeBuckets: []int64{1, 3, -2, 5, -2, 0, -3},
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},
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{
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Schema: 0,
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Count: 36,
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Sum: 1111.1,
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ZeroThreshold: 0.001,
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ZeroCount: 5,
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PositiveSpans: []histogram.Span{
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{Offset: 0, Length: 4},
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{Offset: 0, Length: 0},
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{Offset: 0, Length: 3},
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},
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PositiveBuckets: []int64{1, 2, -2, 2, -1, 0, 0},
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NegativeSpans: []histogram.Span{
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{Offset: 1, Length: 4},
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{Offset: 2, Length: 0},
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{Offset: 2, Length: 3},
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},
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NegativeBuckets: []int64{1, 3, -2, 5, -1, 0, -3},
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},
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}
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expOutput := []*histogram.FloatHistogram{
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{
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Schema: 0,
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Count: 21,
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Sum: 1234.5,
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ZeroThreshold: 0.001,
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ZeroCount: 4,
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PositiveSpans: []histogram.Span{
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{Offset: 0, Length: 4},
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{Offset: 0, Length: 0},
|
|
{Offset: 0, Length: 3},
|
|
},
|
|
PositiveBuckets: []float64{1, 2, 1, 1, 1, 1, 1},
|
|
NegativeSpans: []histogram.Span{
|
|
{Offset: 1, Length: 4},
|
|
{Offset: 2, Length: 0},
|
|
{Offset: 2, Length: 3},
|
|
},
|
|
NegativeBuckets: []float64{1, 2, 1, 2, 2, 2, 2},
|
|
},
|
|
{
|
|
Schema: 0,
|
|
Count: 36,
|
|
Sum: 2345.6,
|
|
ZeroThreshold: 0.001,
|
|
ZeroCount: 5,
|
|
PositiveSpans: []histogram.Span{
|
|
{Offset: 0, Length: 4},
|
|
{Offset: 0, Length: 0},
|
|
{Offset: 0, Length: 3},
|
|
},
|
|
PositiveBuckets: []float64{1, 3, 1, 2, 1, 1, 1},
|
|
NegativeSpans: []histogram.Span{
|
|
{Offset: 1, Length: 4},
|
|
{Offset: 2, Length: 0},
|
|
{Offset: 2, Length: 3},
|
|
},
|
|
NegativeBuckets: []float64{1, 4, 2, 7, 5, 5, 2},
|
|
},
|
|
{
|
|
Schema: 0,
|
|
Count: 36,
|
|
Sum: 1111.1,
|
|
ZeroThreshold: 0.001,
|
|
ZeroCount: 5,
|
|
PositiveSpans: []histogram.Span{
|
|
{Offset: 0, Length: 4},
|
|
{Offset: 0, Length: 0},
|
|
{Offset: 0, Length: 3},
|
|
},
|
|
PositiveBuckets: []float64{1, 3, 1, 3, 2, 2, 2},
|
|
NegativeSpans: []histogram.Span{
|
|
{Offset: 1, Length: 4},
|
|
{Offset: 2, Length: 0},
|
|
{Offset: 2, Length: 3},
|
|
},
|
|
NegativeBuckets: []float64{1, 4, 2, 7, 6, 6, 3},
|
|
},
|
|
}
|
|
|
|
chk := NewHistogramChunk()
|
|
app, err := chk.Appender()
|
|
require.NoError(t, err)
|
|
for i := range input {
|
|
app.AppendHistogram(int64(i), &input[i])
|
|
}
|
|
it := chk.Iterator(nil)
|
|
i := int64(0)
|
|
for it.Next() != ValNone {
|
|
ts, h := it.AtFloatHistogram()
|
|
require.Equal(t, i, ts)
|
|
require.Equal(t, expOutput[i], h, "histogram %d unequal", i)
|
|
i++
|
|
}
|
|
}
|