lib/storage: keep sample with the biggest value on timestamp conflict ()

The change leaves raw sample with the biggest value for identical
timestamps per each `-dedup.minScrapeInterval` discrete interval
when the deduplication is enabled.

```
benchstat old.txt new.txt
name                                         old time/op    new time/op    delta
DeduplicateSamples/minScrapeInterval=1s-10      817ns ± 2%     832ns ± 3%      ~     (p=0.052 n=10+10)
DeduplicateSamples/minScrapeInterval=2s-10     1.56µs ± 1%    2.12µs ± 0%   +35.19%  (p=0.000 n=9+7)
DeduplicateSamples/minScrapeInterval=5s-10     1.32µs ± 3%    1.65µs ± 2%   +25.57%  (p=0.000 n=10+10)
DeduplicateSamples/minScrapeInterval=10s-10    1.13µs ± 2%    1.50µs ± 1%   +32.85%  (p=0.000 n=10+10)

name                                         old speed      new speed      delta
DeduplicateSamples/minScrapeInterval=1s-10   10.0GB/s ± 2%   9.9GB/s ± 3%      ~     (p=0.052 n=10+10)
DeduplicateSamples/minScrapeInterval=2s-10   5.24GB/s ± 1%  3.87GB/s ± 0%   -26.03%  (p=0.000 n=9+7)
DeduplicateSamples/minScrapeInterval=5s-10   6.22GB/s ± 3%  4.96GB/s ± 2%   -20.37%  (p=0.000 n=10+10)
DeduplicateSamples/minScrapeInterval=10s-10  7.28GB/s ± 2%  5.48GB/s ± 1%   -24.74%  (p=0.000 n=10+10)
```

https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3333
Signed-off-by: hagen1778 <roman@victoriametrics.com>

Signed-off-by: hagen1778 <roman@victoriametrics.com>
This commit is contained in:
Roman Khavronenko 2022-12-09 03:06:11 +01:00 committed by Aliaksandr Valialkin
parent 323fc14e0a
commit 909cd04c55
No known key found for this signature in database
GPG Key ID: A72BEC6CD3D0DED1
4 changed files with 96 additions and 22 deletions
app/vmselect/netstorage
docs
lib/storage

View File

@ -171,7 +171,7 @@ func TestMergeSortBlocks(t *testing.T) {
},
}, 1, &Result{
Timestamps: []int64{1, 2, 4, 5, 10, 11, 12},
Values: []float64{21, 22, 23, 7, 24, 5, 26},
Values: []float64{21, 22, 23, 7, 24, 25, 26},
})
// Multiple blocks with identical timestamp ranges, no deduplication.

View File

@ -56,6 +56,7 @@ The following tip changes can be tested by building VictoriaMetrics components f
* FEATURE: [vmalert](https://docs.victoriametrics.com/vmalert.html): add `-remoteWrite.sendTimeout` command-line flag, which allows configuring timeout for sending data to `-remoteWrite.url`. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3408).
* FEATURE: [vmctl](https://docs.victoriametrics.com/vmctl.html): add ability to migrate data between VictoriaMetrics clusters with automatic tenants discovery. See [these docs](https://docs.victoriametrics.com/vmctl.html#cluster-to-cluster-migration-mode) and [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2930).
* FEATURE: [vmctl](https://docs.victoriametrics.com/vmctl.html): add ability to copy data from sources via Prometheus `remote_read` protocol. See [these docs](https://docs.victoriametrics.com/vmctl.html#migrating-data-by-remote-read-protocol). The related issues: [one](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3132) and [two](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1101).
* FEATURE: [deduplication](https://docs.victoriametrics.com/#deduplication): leave raw sample with the biggest value for identical timestamps per each `-dedup.minScrapeInterval` discrete interval when the [deduplication](https://docs.victoriametrics.com/#deduplication) is enabled. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3333).
* FEATURE: [vmui](https://docs.victoriametrics.com/#vmui): allow changing timezones for the requested data. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3075).
* FEATURE: [vmui](https://docs.victoriametrics.com/#vmui): provide fast path for hiding results for all the queries except the given one by clicking `eye` icon with `ctrl` key pressed. See [this feature request](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3446).
* FEATURE: [MetricsQL](https://docs.victoriametrics.com/MetricsQL.html): add `range_trim_spikes(phi, q)` function for trimming `phi` percent of the largest spikes per each time series returned by `q`. See [these docs](https://docs.victoriametrics.com/MetricsQL.html#range_trim_spikes).

View File

@ -34,20 +34,37 @@ func DeduplicateSamples(srcTimestamps []int64, srcValues []float64, dedupInterva
tsNext -= tsNext % dedupInterval
dstTimestamps := srcTimestamps[:0]
dstValues := srcValues[:0]
var tsPrev int64
var value, valuePrev float64
for i, ts := range srcTimestamps[1:] {
value = srcValues[i]
tsCur := srcTimestamps[i]
if tsCur == tsPrev && value < valuePrev {
// prefer biggest value on timestamp conflict
value = valuePrev
}
valuePrev = value
tsPrev = tsCur
if ts <= tsNext {
continue
}
dstTimestamps = append(dstTimestamps, srcTimestamps[i])
dstValues = append(dstValues, srcValues[i])
dstTimestamps = append(dstTimestamps, tsCur)
dstValues = append(dstValues, value)
tsNext += dedupInterval
if tsNext < ts {
tsNext = ts + dedupInterval - 1
tsNext -= tsNext % dedupInterval
}
}
dstTimestamps = append(dstTimestamps, srcTimestamps[len(srcTimestamps)-1])
dstValues = append(dstValues, srcValues[len(srcValues)-1])
ts := srcTimestamps[len(srcTimestamps)-1]
v := srcValues[len(srcValues)-1]
dstTimestamps = append(dstTimestamps, ts)
if ts == tsPrev && v < value {
v = value
}
dstValues = append(dstValues, v)
return dstTimestamps, dstValues
}
@ -60,20 +77,36 @@ func deduplicateSamplesDuringMerge(srcTimestamps, srcValues []int64, dedupInterv
tsNext -= tsNext % dedupInterval
dstTimestamps := srcTimestamps[:0]
dstValues := srcValues[:0]
var tsPrev int64
var value, valuePrev int64
for i, ts := range srcTimestamps[1:] {
value = srcValues[i]
tsCur := srcTimestamps[i]
if tsCur == tsPrev && value < valuePrev {
// prefer biggest value on timestamp conflict
value = valuePrev
}
valuePrev = value
tsPrev = tsCur
if ts <= tsNext {
continue
}
dstTimestamps = append(dstTimestamps, srcTimestamps[i])
dstValues = append(dstValues, srcValues[i])
dstTimestamps = append(dstTimestamps, tsCur)
dstValues = append(dstValues, value)
tsNext += dedupInterval
if tsNext < ts {
tsNext = ts + dedupInterval - 1
tsNext -= tsNext % dedupInterval
}
}
dstTimestamps = append(dstTimestamps, srcTimestamps[len(srcTimestamps)-1])
dstValues = append(dstValues, srcValues[len(srcValues)-1])
ts := srcTimestamps[len(srcTimestamps)-1]
v := srcValues[len(srcValues)-1]
dstTimestamps = append(dstTimestamps, ts)
if ts == tsPrev && v < value {
v = value
}
dstValues = append(dstValues, v)
return dstTimestamps, dstValues
}

View File

@ -38,14 +38,10 @@ func TestNeedsDedup(t *testing.T) {
func TestDeduplicateSamples(t *testing.T) {
// Disable deduplication before exit, since the rest of tests expect disabled dedup.
f := func(scrapeInterval time.Duration, timestamps, timestampsExpected []int64, valuesExpected []float64) {
f := func(scrapeInterval time.Duration, timestamps, timestampsExpected []int64, values, valuesExpected []float64) {
t.Helper()
timestampsCopy := make([]int64, len(timestamps))
values := make([]float64, len(timestamps))
for i, ts := range timestamps {
timestampsCopy[i] = ts
values[i] = float64(i)
}
copy(timestampsCopy, timestamps)
dedupInterval := scrapeInterval.Milliseconds()
timestampsCopy, values = DeduplicateSamples(timestampsCopy, values, dedupInterval)
if !reflect.DeepEqual(timestampsCopy, timestampsExpected) {
@ -65,13 +61,57 @@ func TestDeduplicateSamples(t *testing.T) {
t.Fatalf("invalid DeduplicateSamples(%v) values for the second call;\ngot\n%v\nwant\n%v", timestamps, values, valuesCopy)
}
}
f(time.Millisecond, nil, []int64{}, []float64{})
f(time.Millisecond, []int64{123}, []int64{123}, []float64{0})
f(time.Millisecond, []int64{123, 456}, []int64{123, 456}, []float64{0, 1})
f(time.Millisecond, []int64{0, 0, 0, 1, 1, 2, 3, 3, 3, 4}, []int64{0, 1, 2, 3, 4}, []float64{2, 4, 5, 8, 9})
f(0, []int64{0, 0, 0, 1, 1, 2, 3, 3, 3, 4}, []int64{0, 0, 0, 1, 1, 2, 3, 3, 3, 4}, []float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9})
f(100*time.Millisecond, []int64{0, 100, 100, 101, 150, 180, 205, 300, 1000}, []int64{0, 100, 180, 300, 1000}, []float64{0, 2, 5, 7, 8})
f(10*time.Second, []int64{10e3, 13e3, 21e3, 22e3, 30e3, 33e3, 39e3, 45e3}, []int64{10e3, 13e3, 30e3, 39e3, 45e3}, []float64{0, 1, 4, 6, 7})
f(time.Millisecond, nil, []int64{}, []float64{}, []float64{})
f(time.Millisecond, []int64{123}, []int64{123}, []float64{0}, []float64{0})
f(time.Millisecond, []int64{123, 456}, []int64{123, 456}, []float64{0, 1}, []float64{0, 1})
// pick the biggest value on the interval, no matter what order is
f(time.Millisecond,
[]int64{0, 0, 0, 1, 1, 2, 3, 3, 3, 4},
[]int64{0, 1, 2, 3, 4},
[]float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9},
[]float64{2, 4, 5, 8, 9})
f(time.Millisecond,
[]int64{0, 0, 0, 1, 1, 2, 3, 3, 3, 4},
[]int64{0, 1, 2, 3, 4},
[]float64{2, 1, 0, 3, 4, 5, 7, 6, 8, 9},
[]float64{2, 4, 5, 8, 9})
f(time.Millisecond,
[]int64{0, 0, 0, 1, 1, 2, 3, 3, 3, 4},
[]int64{0, 1, 2, 3, 4},
[]float64{1, 2, 0, 4, 3, 5, 8, 6, 7, 9},
[]float64{2, 4, 5, 8, 9})
// descending values
f(time.Millisecond,
[]int64{0, 0, 0, 1, 1, 2, 3, 3, 3, 4},
[]int64{0, 1, 2, 3, 4},
[]float64{9, 8, 7, 6, 5, 4, 3, 2, 1, 0},
[]float64{9, 6, 4, 3, 0})
f(10*time.Millisecond,
[]int64{0, 9, 11, 13, 13, 29, 29, 29},
[]int64{0, 9, 13, 29},
[]float64{5, 1, 0, 4, 1, 3, 0, 5},
[]float64{5, 1, 4, 5})
// too small dedup interval
f(0,
[]int64{0, 0, 0, 1, 1, 2, 3, 3, 3, 4},
[]int64{0, 0, 0, 1, 1, 2, 3, 3, 3, 4},
[]float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9},
[]float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9})
f(100*time.Millisecond,
[]int64{0, 100, 100, 101, 150, 180, 205, 300, 1000},
[]int64{0, 100, 180, 300, 1000},
[]float64{0, 1, 2, 3, 4, 5, 6, 7, 8},
[]float64{0, 2, 5, 7, 8})
f(10*time.Second,
[]int64{10e3, 13e3, 21e3, 22e3, 30e3, 33e3, 39e3, 45e3},
[]int64{10e3, 13e3, 30e3, 39e3, 45e3},
[]float64{0, 1, 2, 3, 4, 5, 6, 7},
[]float64{0, 1, 4, 6, 7})
}
func TestDeduplicateSamplesDuringMerge(t *testing.T) {