app/vmselect/promql: add quantile("phiLabel", phi1, ..., phiN, q) aggregate function to MetricsQL

See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1573

app/vmselect/promql/aggr.go

@@ -48,6 +48,7 @@ var aggrFuncs = map[string]aggrFunc{
 	"outliersk":      aggrFuncOutliersK,
 	"mode":           newAggrFunc(aggrFuncMode),
 	"zscore":         aggrFuncZScore,
+	"quantiles":      aggrFuncQuantiles,
 }
 
 type aggrFunc func(afa *aggrFuncArg) ([]*timeseries, error)
@@ -883,6 +884,42 @@ func aggrFuncLimitK(afa *aggrFuncArg) ([]*timeseries, error) {
 	return aggrFuncExt(afe, args[1], &afa.ae.Modifier, afa.ae.Limit, true)
 }
 
+func aggrFuncQuantiles(afa *aggrFuncArg) ([]*timeseries, error) {
+	args := afa.args
+	if len(args) < 3 {
+		return nil, fmt.Errorf("unexpected number of args: %d; expecting at least 3 args", len(args))
+	}
+	dstLabel, err := getString(args[0], 0)
+	if err != nil {
+		return nil, fmt.Errorf("cannot obtain dstLabel: %w", err)
+	}
+	phiArgs := args[1 : len(args)-1]
+	argOrig := args[len(args)-1]
+	var rvs []*timeseries
+	for i, phiArg := range phiArgs {
+		phis, err := getScalar(phiArg, i+1)
+		if err != nil {
+			return nil, err
+		}
+		if len(phis) == 0 {
+			logger.Panicf("BUG: expecting at least a single sample")
+		}
+		phi := phis[0]
+		afe := newAggrQuantileFunc(phis)
+		arg := copyTimeseries(argOrig)
+		tss, err := aggrFuncExt(afe, arg, &afa.ae.Modifier, afa.ae.Limit, false)
+		if err != nil {
+			return nil, fmt.Errorf("cannot calculate quantile %g: %w", phi, err)
+		}
+		for _, ts := range tss {
+			ts.MetricName.RemoveTag(dstLabel)
+			ts.MetricName.AddTag(dstLabel, fmt.Sprintf("%g", phi))
+		}
+		rvs = append(rvs, tss...)
+	}
+	return rvs, nil
+}
+
 func aggrFuncQuantile(afa *aggrFuncArg) ([]*timeseries, error) {
 	args := afa.args
 	if err := expectTransformArgsNum(args, 2); err != nil {

app/vmselect/promql/exec_test.go

@@ -5461,6 +5461,30 @@ func TestExecSuccess(t *testing.T) {
 		resultExpected := []netstorage.Result{r}
 		f(q, resultExpected)
 	})
+	t.Run(`quantiles("phi", 0.2, 0.5)`, func(t *testing.T) {
+		t.Parallel()
+		q := `sort(quantiles("phi", 0.2, 0.5, label_set(10, "foo", "bar") or label_set(time()/150, "baz", "sss")))`
+		r1 := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{6.666666666666667, 8, 9.333333333333334, 10, 10, 10},
+			Timestamps: timestampsExpected,
+		}
+		r1.MetricName.Tags = []storage.Tag{{
+			Key:   []byte("phi"),
+			Value: []byte("0.2"),
+		}}
+		r2 := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{10, 10, 10, 10.666666666666666, 12, 13.333333333333334},
+			Timestamps: timestampsExpected,
+		}
+		r2.MetricName.Tags = []storage.Tag{{
+			Key:   []byte("phi"),
+			Value: []byte("0.5"),
+		}}
+		resultExpected := []netstorage.Result{r1, r2}
+		f(q, resultExpected)
+	})
 	t.Run(`median()`, func(t *testing.T) {
 		t.Parallel()
 		q := `median(label_set(10, "foo", "bar") or label_set(time()/150, "baz", "sss"))`
@@ -6961,6 +6985,7 @@ func TestExecError(t *testing.T) {
 	f(`bitmap_and()`)
 	f(`bitmap_or()`)
 	f(`bitmap_xor()`)
+	f(`quantiles()`)
 
 	// Invalid argument type
 	f(`median_over_time({}, 2)`)

app/vmselect/promql/transform.go

@@ -2016,6 +2016,17 @@ func transformEnd(tfa *transformFuncArg) float64 {
 	return float64(tfa.ec.End) / 1e3
 }
 
+// copyTimeseries returns a copy of tss.
+func copyTimeseries(tss []*timeseries) []*timeseries {
+	rvs := make([]*timeseries, len(tss))
+	for i, src := range tss {
+		var dst timeseries
+		dst.CopyFromShallowTimestamps(src)
+		rvs[i] = &dst
+	}
+	return rvs
+}
+
 // copyTimeseriesMetricNames returns a copy of tss with real copy of MetricNames,
 // but with shallow copy of Timestamps and Values if makeCopy is set.
 //
@@ -2033,7 +2044,7 @@ func copyTimeseriesMetricNames(tss []*timeseries, makeCopy bool) []*timeseries {
 	return rvs
 }
 
-// copyShallow returns a copy of arg with shallow copies of MetricNames,
+// copyTimeseriesShallow returns a copy of arg with shallow copies of MetricNames,
 // Timestamps and Values.
 func copyTimeseriesShallow(arg []*timeseries) []*timeseries {
 	rvs := make([]*timeseries, len(arg))

docs/CHANGELOG.md

@@ -13,6 +13,7 @@ sort: 15
 * FEATURE: update Go builder from v1.16.7 to v1.17.0. This improves data ingestion and query performance by up to 5% according to benchmarks. See [the release post for Go1.17](https://go.dev/blog/go1.17).
 * FEATURE: vmagent: expose `promscrape_discovery_http_errors_total` metric, which can be used for monitoring the number of failed discovery attempts per each `http_sd` config.
 * FEATURE: do not reset response cache when a sample with old timestamp is ingested into VictoriaMetrics if `-search.disableAutoCacheReset` command-line option is set. See [this feature request](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1570).
+* FEATURE: add `quantiles("quantileLabel", phi1, ..., phiN, q)` aggregate function to [MetricsQL](https://docs.victoriametrics.com/MetricsQL.html), which calculates the given `phi*` quantiles over time series returned by `q`. See [this feature request](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1573).
 
 * BUGFIX: rename `sign` function to `sgn` in order to be consistent with PromQL. See [this pull request from Prometheus](https://github.com/prometheus/prometheus/pull/8457).
 * BUGFIX: improve the detection of the needed free space for background merge operation. This should prevent from possible out of disk space crashes during big merges. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1560).

docs/MetricsQL.md

@@ -770,7 +770,11 @@ See also [implicit query conversions](#implicit-query-conversions).
 
 #### quantile
 
-`quantile(phi, q) by (group_labels)` calculates `phi`-quantile per each `group_labels` for all the time series returned by `q`. The aggregate is calculated individually per each group of points with the same timestamp. This function is supported by PromQL.
+`quantile(phi, q) by (group_labels)` calculates `phi`-quantile per each `group_labels` for all the time series returned by `q`. The aggregate is calculated individually per each group of points with the same timestamp. This function is supported by PromQL. See also [quantiles](#quantiles).
+
+#### quantiles
+
+`quantiles("quantileLabel", phi1, ..., phiN, q)` calculates `phi*`-quantiles for all the time series returned by `q` and return them in time series with `{quantileLabel="phi*"}` label. The aggregate is calculated individually per each group of points with the same timestamp. See also [quantile](#quantile).
 
 #### stddev
 

go.mod

@@ -9,7 +9,7 @@ require (
 	// like https://github.com/valyala/fasthttp/commit/996610f021ff45fdc98c2ce7884d5fa4e7f9199b
 	github.com/VictoriaMetrics/fasthttp v1.0.16
 	github.com/VictoriaMetrics/metrics v1.17.3
-	github.com/VictoriaMetrics/metricsql v0.20.0
+	github.com/VictoriaMetrics/metricsql v0.21.0
 	github.com/VividCortex/ewma v1.2.0 // indirect
 	github.com/aws/aws-sdk-go v1.40.30
 	github.com/cespare/xxhash/v2 v2.1.2

go.sum

@@ -108,8 +108,8 @@ github.com/VictoriaMetrics/fasthttp v1.0.16/go.mod h1:s9o5H4T58Kt4CTrdyJp4RorBKC
 github.com/VictoriaMetrics/metrics v1.12.2/go.mod h1:Z1tSfPfngDn12bTfZSCqArT3OPY3u88J12hSoOhuiRE=
 github.com/VictoriaMetrics/metrics v1.17.3 h1:QPUakR6JRy8BhL2C2kOgYKLuoPDwtJQ+7iKIZSjt1A4=
 github.com/VictoriaMetrics/metrics v1.17.3/go.mod h1:Z1tSfPfngDn12bTfZSCqArT3OPY3u88J12hSoOhuiRE=
-github.com/VictoriaMetrics/metricsql v0.20.0 h1:1rL/naP4+PXdY3Hg5Oj8+Ql+NZCIHzl/OjTmOdg3+mM=
+github.com/VictoriaMetrics/metricsql v0.21.0 h1:wA/IVfRFQaThy4bM1kAmPiCR0BkWv4tEXD9lBF+GPdU=
-github.com/VictoriaMetrics/metricsql v0.20.0/go.mod h1:ylO7YITho/Iw6P71oEaGyHbO94bGoGtzWfLGqFhMIg8=
+github.com/VictoriaMetrics/metricsql v0.21.0/go.mod h1:ylO7YITho/Iw6P71oEaGyHbO94bGoGtzWfLGqFhMIg8=
 github.com/VividCortex/ewma v1.1.1/go.mod h1:2Tkkvm3sRDVXaiyucHiACn4cqf7DpdyLvmxzcbUokwA=
 github.com/VividCortex/ewma v1.2.0 h1:f58SaIzcDXrSy3kWaHNvuJgJ3Nmz59Zji6XoJR/q1ow=
 github.com/VividCortex/ewma v1.2.0/go.mod h1:nz4BbCtbLyFDeC9SUHbtcT5644juEuWfUAUnGx7j5l4=

vendor/github.com/VictoriaMetrics/metricsql/aggr.go

@@ -38,6 +38,7 @@ var aggrFuncs = map[string]bool{
 	"outliersk":      true,
 	"mode":           true,
 	"zscore":         true,
+	"quantiles":      true,
 }
 
 func isAggrFunc(s string) bool {

vendor/modules.txt

@@ -21,7 +21,7 @@ github.com/VictoriaMetrics/fasthttp/stackless
 # github.com/VictoriaMetrics/metrics v1.17.3
 ## explicit
 github.com/VictoriaMetrics/metrics
-# github.com/VictoriaMetrics/metricsql v0.20.0
+# github.com/VictoriaMetrics/metricsql v0.21.0
 ## explicit
 github.com/VictoriaMetrics/metricsql
 github.com/VictoriaMetrics/metricsql/binaryop