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MQE improve memory consumption estimate with Label information #11203

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663f0f9
Add LabelPairEstimatedSize
lamida Apr 13, 2025
1dd8186
Update comment
lamida Apr 13, 2025
1a8f91f
Move 10 label pairs per series into the estimate constant
lamida Apr 13, 2025
368f89b
Update test with label pair estimate
lamida Apr 13, 2025
aa6c2d2
Remove unnecessary overhead in the label estimate
lamida Apr 13, 2025
90d6fbd
Update estimate labels to use SizeOf Label
lamida Apr 13, 2025
3c46868
Update comment
lamida Apr 13, 2025
35ea1a1
Update comment
lamida Apr 13, 2025
f3c3cdd
Small refactoring
lamida Apr 13, 2025
223c40a
Update instant query limit size in test
lamida Apr 14, 2025
345e125
Add many labels and long labels test
lamida Apr 14, 2025
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34 changes: 19 additions & 15 deletions pkg/streamingpromql/engine_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1505,7 +1505,7 @@ func TestMemoryConsumptionLimit_SingleQueries(t *testing.T) {

// At peak, we'll hold all the output samples plus one series, which has one sample.
// The output contains five samples, which will be rounded up to 8 (the nearest power of two).
instantQueryExpectedPeak: types.FPointSize + 8*types.VectorSampleSize,
instantQueryExpectedPeak: types.FPointSize + 8*(types.VectorSampleSize+types.LabelPairEstimatedSize),
instantQueryLimit: 0,
},
"limit enabled, but query does not exceed limit": {
Expand All @@ -1518,8 +1518,8 @@ func TestMemoryConsumptionLimit_SingleQueries(t *testing.T) {

// At peak, we'll hold all the output samples plus one series, which has one sample.
// The output contains five samples, which will be rounded up to 8 (the nearest power of two).
instantQueryExpectedPeak: types.FPointSize + 8*types.VectorSampleSize,
instantQueryLimit: 1000,
instantQueryExpectedPeak: types.FPointSize + 8*(types.VectorSampleSize+types.LabelPairEstimatedSize),
instantQueryLimit: types.FPointSize + 8*(types.VectorSampleSize+types.LabelPairEstimatedSize),
},
"limit enabled, and query exceeds limit": {
expr: "some_metric",
Expand Down Expand Up @@ -1548,9 +1548,10 @@ func TestMemoryConsumptionLimit_SingleQueries(t *testing.T) {
// At peak we'll hold in memory:
// - the running total for the sum() (two floats and a bool),
// - the next series from the selector,
// - and the output sample.
instantQueryExpectedPeak: 2*types.Float64Size + types.BoolSize + types.FPointSize + types.VectorSampleSize,
instantQueryLimit: 2*types.Float64Size + types.BoolSize + types.FPointSize + types.VectorSampleSize,
// - the output sample,
// - and the sample labels.
instantQueryExpectedPeak: 2*types.Float64Size + types.BoolSize + types.FPointSize + types.VectorSampleSize + types.LabelPairEstimatedSize,
instantQueryLimit: 2*types.Float64Size + types.BoolSize + types.FPointSize + types.VectorSampleSize + types.LabelPairEstimatedSize,
},
"limit enabled, query selects more samples than limit but should not load all of them into memory at once, and peak consumption is over limit": {
expr: "sum(some_metric)",
Expand All @@ -1568,10 +1569,11 @@ func TestMemoryConsumptionLimit_SingleQueries(t *testing.T) {
// At peak we'll hold in memory:
// - the running total for the sum() (two floats and a bool),
// - the next series from the selector,
// - and the output sample.
// - the output sample,
// - and the sample labels.
// The last thing to be allocated is the bool slice for the running total, so that won't contribute to the peak before the query is aborted.
instantQueryExpectedPeak: 2*types.Float64Size + types.FPointSize + types.VectorSampleSize,
instantQueryLimit: 2*types.Float64Size + types.BoolSize + types.FPointSize + types.VectorSampleSize - 1,
instantQueryExpectedPeak: 2*types.Float64Size + types.FPointSize + types.VectorSampleSize + types.LabelPairEstimatedSize,
instantQueryLimit: 2*types.Float64Size + types.BoolSize + types.FPointSize + types.VectorSampleSize + types.LabelPairEstimatedSize - 1,
},
"histogram: limit enabled, but query does not exceed limit": {
expr: "sum(some_histogram)",
Expand All @@ -1587,9 +1589,10 @@ func TestMemoryConsumptionLimit_SingleQueries(t *testing.T) {
// At peak we'll hold in memory:
// - the running total for the sum() (a histogram pointer),
// - the next series from the selector,
// - and the output sample.
instantQueryExpectedPeak: types.HistogramPointerSize + types.HPointSize + types.VectorSampleSize,
instantQueryLimit: types.HistogramPointerSize + types.HPointSize + types.VectorSampleSize,
// - the output sample,
// - and the sample labels.
instantQueryExpectedPeak: types.HistogramPointerSize + types.HPointSize + types.VectorSampleSize + types.LabelPairEstimatedSize,
instantQueryLimit: types.HistogramPointerSize + types.HPointSize + types.VectorSampleSize + types.LabelPairEstimatedSize,
},
"histogram: limit enabled, and query exceeds limit": {
expr: "sum(some_histogram)",
Expand All @@ -1606,10 +1609,11 @@ func TestMemoryConsumptionLimit_SingleQueries(t *testing.T) {
// At peak we'll hold in memory:
// - the running total for the sum() (a histogram pointer),
// - the next series from the selector,
// - and the output sample.
// - the output sample,
// - and the sample labels.
// The last thing to be allocated is the HistogramPointerSize slice for the running total, so that won't contribute to the peak before the query is aborted.
instantQueryExpectedPeak: types.HPointSize + types.VectorSampleSize,
instantQueryLimit: types.HistogramPointerSize + types.HPointSize + types.VectorSampleSize - 1,
instantQueryExpectedPeak: types.HPointSize + types.VectorSampleSize + types.LabelPairEstimatedSize,
instantQueryLimit: types.HistogramPointerSize + types.HPointSize + types.VectorSampleSize + types.LabelPairEstimatedSize - 1,
},
}

Expand Down
24 changes: 23 additions & 1 deletion pkg/streamingpromql/types/limiting_pool.go
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ import (
"unsafe"

"github.com/prometheus/prometheus/model/histogram"
"github.com/prometheus/prometheus/model/labels"
"github.com/prometheus/prometheus/promql"

"github.com/grafana/mimir/pkg/streamingpromql/limiting"
Expand All @@ -24,6 +25,15 @@ const (
// (5 * 8 bytes). Some FloatHistograms will be bigger than this and some will be smaller.
nativeHistogramEstimatedSize = 288

// Estimated size of a label pair (name + value) in bytes.
// This is a conservative estimate that includes:
// - The size of Label struct
// - Average name length (8 bytes)
// - Average value length (8 bytes)
// - Average total of labels per series (10)
// The last 3 averages value are taken based on guesstimate.
LabelPairEstimatedSize = (uint64(unsafe.Sizeof(labels.Label{})) + 8 + 8) * 10

FPointSize = uint64(unsafe.Sizeof(promql.FPoint{}))
HPointSize = uint64(unsafe.Sizeof(promql.HPoint{}) + nativeHistogramEstimatedSize)
VectorSampleSize = uint64(unsafe.Sizeof(promql.Sample{})) // This assumes each sample is a float sample, not a histogram.
Expand Down Expand Up @@ -176,6 +186,11 @@ func (p *LimitingBucketedPool[S, E]) Get(size int, tracker *limiting.MemoryConsu
// - there's no guarantee the slice will have size 'size' when it's returned to us in putWithElementSize, so using 'size' would make the accounting below impossible
estimatedBytes := uint64(cap(s)) * p.elementSize

// Series labels must be estimated only for VectorPool.
if _, isVector := any(s).(promql.Vector); isVector {
estimatedBytes += uint64(cap(s)) * LabelPairEstimatedSize
}

if err := tracker.IncreaseMemoryConsumption(estimatedBytes); err != nil {
p.inner.Put(s)
return nil, err
Expand All @@ -200,7 +215,14 @@ func (p *LimitingBucketedPool[S, E]) Put(s S, tracker *limiting.MemoryConsumptio
}
}

tracker.DecreaseMemoryConsumption(uint64(cap(s)) * p.elementSize)
estimatedBytes := uint64(cap(s)) * p.elementSize

// Series labels must be estimated only for VectorPool.
if _, isVector := any(s).(promql.Vector); isVector {
estimatedBytes += uint64(cap(s)) * LabelPairEstimatedSize
}

tracker.DecreaseMemoryConsumption(estimatedBytes)
p.inner.Put(s)
}

Expand Down
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