app/vmselect/promql: add rollup_scrape_interval(m[d]) function

It calculates the min, max and avg scrape intervals for m over the given lookbehind window d

app/vmselect/promql/exec_test.go

@@ -6466,6 +6466,39 @@ func TestExecSuccess(t *testing.T) {
 		resultExpected := []netstorage.Result{r1, r2, r3}
 		f(q, resultExpected)
 	})
+	t.Run(`rollup_scrape_interval()`, func(t *testing.T) {
+		t.Parallel()
+		q := `sort_by_label(rollup_scrape_interval(1[5m:10s]), "rollup")`
+		r1 := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{10, 10, 10, 10, 10, 10},
+			Timestamps: timestampsExpected,
+		}
+		r1.MetricName.Tags = []storage.Tag{{
+			Key:   []byte("rollup"),
+			Value: []byte("avg"),
+		}}
+		r2 := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{10, 10, 10, 10, 10, 10},
+			Timestamps: timestampsExpected,
+		}
+		r2.MetricName.Tags = []storage.Tag{{
+			Key:   []byte("rollup"),
+			Value: []byte("max"),
+		}}
+		r3 := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{10, 10, 10, 10, 10, 10},
+			Timestamps: timestampsExpected,
+		}
+		r3.MetricName.Tags = []storage.Tag{{
+			Key:   []byte("rollup"),
+			Value: []byte("min"),
+		}}
+		resultExpected := []netstorage.Result{r1, r2, r3}
+		f(q, resultExpected)
+	})
 	t.Run(`rollup()`, func(t *testing.T) {
 		t.Parallel()
 		q := `sort(rollup(time()[:50s]))`

app/vmselect/promql/rollup.go

@@ -76,6 +76,7 @@ var rollupFuncs = map[string]newRollupFunc{
 	"rollup_delta":           newRollupFuncOneArg(rollupFake),
 	"rollup_increase":        newRollupFuncOneArg(rollupFake), // + rollupFuncsRemoveCounterResets
 	"rollup_candlestick":     newRollupFuncOneArg(rollupFake),
+	"rollup_scrape_interval": newRollupFuncOneArg(rollupFake),
 	"aggr_over_time":         newRollupFuncTwoArgs(rollupFake),
 	"hoeffding_bound_upper":  newRollupHoeffdingBoundUpper,
 	"hoeffding_bound_lower":  newRollupHoeffdingBoundLower,
@@ -319,6 +320,24 @@ func getRollupConfigs(name string, rf rollupFunc, expr metricsql.Expr, start, en
 		rcs = append(rcs, newRollupConfig(rollupClose, "close"))
 		rcs = append(rcs, newRollupConfig(rollupLow, "low"))
 		rcs = append(rcs, newRollupConfig(rollupHigh, "high"))
+	case "rollup_scrape_interval":
+		preFuncPrev := preFunc
+		preFunc = func(values []float64, timestamps []int64) {
+			preFuncPrev(values, timestamps)
+			// Calculate intervals in seconds between samples.
+			tsSecsPrev := nan
+			for i, ts := range timestamps {
+				tsSecs := float64(ts) / 1000
+				values[i] = tsSecs - tsSecsPrev
+				tsSecsPrev = tsSecs
+			}
+			if len(values) > 1 {
+				// Overwrite the first NaN interval with the second interval,
+				// So min, max and avg rollups could be calculated properly, since they don't expect to receive NaNs.
+				values[0] = values[1]
+			}
+		}
+		rcs = appendRollupConfigs(rcs)
 	case "aggr_over_time":
 		aggrFuncNames, err := getRollupAggrFuncNames(expr)
 		if err != nil {

docs/CHANGELOG.md

@@ -8,6 +8,7 @@ sort: 15
 
 * FEATURE: vmagent [enterprise](https://victoriametrics.com/enterprise.html): add support for data reading from [Apache Kafka](https://kafka.apache.org/).
 * FEATURE: calculate quantiles in the same way as Prometheus does in such functions as [quantile_over_time](https://docs.victoriametrics.com/MetricsQL.html#quantile_over_time) and [quantile](https://docs.victoriametrics.com/MetricsQL.html#quantile). Previously results from VictoriaMetrics could be slightly different than results from Prometheus. See [this](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1625) and [this](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1612) issues.
+* FEATURE: add `rollup_scrape_interval(m[d])` function to [MetricsQL](https://docs.victoriametrics.com/MetricsQL.html), which returns `min`, `max` and `avg` values for the interval between samples for `m` on the given lookbehind window `d`.
 
 * BUGFIX: align behavior of the queries `a or on (labels) b`, `a and on (labels) b` and `a unless on (labels) b` where `b` has multiple time series with the given `labels` to Prometheus behavior. See [this pull request](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/1643).
 

docs/MetricsQL.md

@@ -274,9 +274,13 @@ See also [implicit query conversions](#implicit-query-conversions).
 
 `rollup_rate(series_selector[d])` calculates per-second change rates for adjancent raw samples on the given lookbehind window `d` and returns `min`, `max` and `avg` values for the calculated per-second change rates. The calculations are perfomed individually per each time series returned from the given [series_selector](https://prometheus.io/docs/prometheus/latest/querying/basics/#time-series-selectors). Metric names are stripped from the resulting rollups.
 
+#### rollup_scrape_interval
+
+`rollup_scrape_interval(series_selector[d])` calculates the interval in seconds between adjancent raw samples on the given lookbehind window `d` and returns `min`, `max` and `avg` values for the calculated interval. The calculations are perfomed individually per each time series returned from the given [series_selector](https://prometheus.io/docs/prometheus/latest/querying/basics/#time-series-selectors). Metric names are stripped from the resulting rollups. See also [scrape_interval](#scrape_interval).
+
 #### scrape_interval
 
-`scrape_interval(series_selector[d])` calculates the average interval in seconds between raw samples on the given lookbehind window `d` per each time series returned from the given [series_selector](https://prometheus.io/docs/prometheus/latest/querying/basics/#time-series-selectors). Metric names are stripped from the resulting rollups.
+`scrape_interval(series_selector[d])` calculates the average interval in seconds between raw samples on the given lookbehind window `d` per each time series returned from the given [series_selector](https://prometheus.io/docs/prometheus/latest/querying/basics/#time-series-selectors). Metric names are stripped from the resulting rollups. See also [rollup_scrape_interval](#rollup_scrape_interval).
 
 #### share_gt_over_time
 

go.mod

@@ -9,7 +9,7 @@ require (
 	// like https://github.com/valyala/fasthttp/commit/996610f021ff45fdc98c2ce7884d5fa4e7f9199b
 	github.com/VictoriaMetrics/fasthttp v1.1.0
 	github.com/VictoriaMetrics/metrics v1.18.0
-	github.com/VictoriaMetrics/metricsql v0.24.0
+	github.com/VictoriaMetrics/metricsql v0.25.0
 	github.com/VividCortex/ewma v1.2.0 // indirect
 	github.com/aws/aws-sdk-go v1.40.49
 	github.com/cespare/xxhash/v2 v2.1.2
@@ -30,7 +30,6 @@ require (
 	github.com/valyala/fastrand v1.1.0
 	github.com/valyala/fasttemplate v1.2.1
 	github.com/valyala/gozstd v1.13.0
-	github.com/valyala/histogram v1.2.0
 	github.com/valyala/quicktemplate v1.7.0
 	golang.org/x/net v0.0.0-20210924151903-3ad01bbaa167
 	golang.org/x/oauth2 v0.0.0-20210819190943-2bc19b11175f

go.sum

@@ -110,8 +110,8 @@ github.com/VictoriaMetrics/fasthttp v1.1.0/go.mod h1:/7DMcogqd+aaD3G3Hg5kFgoFwlR
 github.com/VictoriaMetrics/metrics v1.12.2/go.mod h1:Z1tSfPfngDn12bTfZSCqArT3OPY3u88J12hSoOhuiRE=
 github.com/VictoriaMetrics/metrics v1.18.0 h1:vov5NxDHRSXFbdiH4dYLYEjKLoAXXSQ7hcnG8TSD9JQ=
 github.com/VictoriaMetrics/metrics v1.18.0/go.mod h1:ArjwVz7WpgpegX/JpB0zpNF2h2232kErkEnzH1sxMmA=
-github.com/VictoriaMetrics/metricsql v0.24.0 h1:1SOiuEaSgfS2CiQyCAlYQs3WPHzXNMPUSXtE1Zx6qDw=
+github.com/VictoriaMetrics/metricsql v0.25.0 h1:7bjs82RYWpO/myqfXLZIIn7VMWwWd9qPgiBhsIG7c8s=
-github.com/VictoriaMetrics/metricsql v0.24.0/go.mod h1:ylO7YITho/Iw6P71oEaGyHbO94bGoGtzWfLGqFhMIg8=
+github.com/VictoriaMetrics/metricsql v0.25.0/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/rollup.go

@@ -62,6 +62,7 @@ var rollupFuncs = map[string]bool{
 	"rollup_delta":           true,
 	"rollup_increase":        true,
 	"rollup_candlestick":     true,
+	"rollup_scrape_interval": true,
 	"aggr_over_time":         true,
 	"hoeffding_bound_upper":  true,
 	"hoeffding_bound_lower":  true,

vendor/modules.txt

@@ -22,7 +22,7 @@ github.com/VictoriaMetrics/fasthttp/stackless
 # github.com/VictoriaMetrics/metrics v1.18.0
 ## explicit
 github.com/VictoriaMetrics/metrics
-# github.com/VictoriaMetrics/metricsql v0.24.0
+# github.com/VictoriaMetrics/metricsql v0.25.0
 ## explicit
 github.com/VictoriaMetrics/metricsql
 github.com/VictoriaMetrics/metricsql/binaryop
@@ -214,7 +214,6 @@ github.com/valyala/fasttemplate
 ## explicit
 github.com/valyala/gozstd
 # github.com/valyala/histogram v1.2.0
-## explicit
 github.com/valyala/histogram
 # github.com/valyala/quicktemplate v1.7.0
 ## explicit