make 1 single pointslicepool type that has a GetMin() method

while we're at it, add some syntactic sugar

api/dataprocessor.go

@@ -71,16 +71,10 @@ func Fix(in []schema.Point, from, to, interval uint32) []schema.Point {
 		// the requested range is too narrow for the requested interval
 		return []schema.Point{}
 	}
-	// try to get a sufficiently sized slice from the pool. if it fails, allocate a new one.
-	var out []schema.Point
+
 	neededCap := int((last-first)/interval + 1)
-	candidate := pointSlicePool.Get().([]schema.Point)
-	if cap(candidate) >= neededCap {
-		out = candidate[:neededCap]
-	} else {
-		pointSlicePool.Put(candidate)
-		out = make([]schema.Point, neededCap)
-	}
+	out := pointSlicePool.GetMin(neededCap)
+	out = out[:neededCap]
 
 	// i iterates in. o iterates out. t is the ts we're looking to fill.
 	for t, i, o := first, 0, -1; t <= last; t += interval {
@@ -120,7 +114,7 @@ func Fix(in []schema.Point, from, to, interval uint32) []schema.Point {
 			o -= 1
 		}
 	}
-	pointSlicePool.Put(in[:0])
+	pointSlicePool.Put(in)
 
 	return out
 }
@@ -146,7 +140,7 @@ func divide(pointsA, pointsB []schema.Point) []schema.Point {
 	for i := range pointsA {
 		pointsA[i].Val /= pointsB[i].Val
 	}
-	pointSlicePool.Put(pointsB[:0])
+	pointSlicePool.Put(pointsB)
 	return pointsA
 }
 
@@ -480,7 +474,7 @@ func (s *Server) getSeries(ctx *requestContext, ss *models.StorageStats) (mdata.
 func (s *Server) itersToPoints(ctx *requestContext, iters []tsz.Iter) []schema.Point {
 	pre := time.Now()
 
-	points := pointSlicePool.Get().([]schema.Point)
+	points := pointSlicePool.Get()
 	for _, iter := range iters {
 		total := 0
 		good := 0
@@ -666,7 +660,7 @@ func mergeSeries(in []models.Series, dataMap expr.DataMap) []models.Series {
 				}
 			}
 			for j := 1; j < len(series); j++ {
-				pointSlicePool.Put(series[j].Datapoints[:0])
+				pointSlicePool.Put(series[j].Datapoints)
 			}
 			merged[i] = series[0]
 			for j := 1; j < len(series); j++ {

api/init.go

@@ -1,25 +1,13 @@
 package api
 
 import (
-	"sync"
-
 	"github.com/grafana/metrictank/expr"
-	"github.com/grafana/metrictank/schema"
+	"github.com/grafana/metrictank/pointslicepool"
 )
 
-// default size is probably bigger than what most responses need, but it saves [re]allocations
-// also it's possible that occasionnally more size is needed, causing a realloc of underlying array, and that extra space will stick around until next GC run.
-const defaultPointSliceSize = 2000
-
-var pointSlicePool sync.Pool
-
-func pointSlicePoolAllocNew() interface{} {
-	return make([]schema.Point, 0, defaultPointSliceSize)
-}
+var pointSlicePool *pointslicepool.PointSlicePool
 
 func init() {
-	pointSlicePool = sync.Pool{
-		New: pointSlicePoolAllocNew,
-	}
-	expr.Pool(&pointSlicePool)
+	pointSlicePool = pointslicepool.New(pointslicepool.DefaultPointSliceSize)
+	expr.Pool(pointSlicePool)
 }

expr/datamap.go

@@ -26,7 +26,7 @@ func (dm DataMap) Add(r Req, s ...models.Series) {
 func (dm DataMap) Clean() {
 	for _, series := range dm {
 		for _, serie := range series {
-			pointSlicePool.Put(serie.Datapoints[:0])
+			pointSlicePool.Put(serie.Datapoints)
 		}
 	}
 }

expr/func_absolute.go

@@ -5,7 +5,6 @@ import (
 	"math"
 
 	"github.com/grafana/metrictank/api/models"
-	"github.com/grafana/metrictank/schema"
 )
 
 type FuncAbsolute struct {
@@ -36,7 +35,7 @@ func (s *FuncAbsolute) Exec(dataMap DataMap) ([]models.Series, error) {
 		serie.Target = fmt.Sprintf("absolute(%s)", serie.Target)
 		serie.Tags = serie.CopyTagsWith("absolute", "1")
 		serie.QueryPatt = fmt.Sprintf("absolute(%s)", serie.QueryPatt)
-		out := pointSlicePool.Get().([]schema.Point)
+		out := pointSlicePool.Get()
 		for _, p := range serie.Datapoints {
 			p.Val = math.Abs(p.Val)
 			out = append(out, p)

expr/func_aggregate.go

@@ -6,7 +6,6 @@ import (
 	"unsafe"
 
 	"github.com/grafana/metrictank/api/models"
-	"github.com/grafana/metrictank/schema"
 )
 
 type FuncAggregate struct {
@@ -69,7 +68,7 @@ func aggregate(dataMap DataMap, series []models.Series, queryPatts []string, agg
 		series[0].QueryPatt = name
 		return series, nil
 	}
-	out := pointSlicePool.Get().([]schema.Point)
+	out := pointSlicePool.Get()
 
 	agg.function(series, &out)
 

expr/func_aspercent.go

@@ -121,7 +121,7 @@ func (s *FuncAsPercent) execWithNodes(in, totals []models.Series, dataMap DataMa
 			nonesSerie.Tags = map[string]string{"name": nonesSerie.Target}
 
 			if nones == nil {
-				nones = pointSlicePool.Get().([]schema.Point)
+				nones = pointSlicePool.Get()
 				for _, p := range totalSerieByKey[key].Datapoints {
 					p.Val = math.NaN()
 					nones = append(nones, p)
@@ -144,7 +144,7 @@ func (s *FuncAsPercent) execWithNodes(in, totals []models.Series, dataMap DataMa
 				nonesSerie.Meta = serie1.Meta.Copy()
 
 				if nones == nil {
-					nones = pointSlicePool.Get().([]schema.Point)
+					nones = pointSlicePool.Get()
 					for _, p := range serie1.Datapoints {
 						p.Val = math.NaN()
 						nones = append(nones, p)
@@ -157,7 +157,7 @@ func (s *FuncAsPercent) execWithNodes(in, totals []models.Series, dataMap DataMa
 			} else {
 				// key found in both inByKey and totalSerieByKey
 				serie1, serie2 := NormalizeTwo(dataMap, serie1, totalSerieByKey[key])
-				serie1 = serie1.Copy(pointSlicePool.Get().([]schema.Point))
+				serie1 = serie1.Copy(pointSlicePool.Get())
 				serie1.QueryPatt = fmt.Sprintf("asPercent(%s,%s)", serie1.QueryPatt, serie2.QueryPatt)
 				serie1.Target = fmt.Sprintf("asPercent(%s,%s)", serie1.Target, serie2.Target)
 				serie1.Tags = map[string]string{"name": serie1.Target}
@@ -216,12 +216,12 @@ func (s *FuncAsPercent) execWithoutNodes(in, totals []models.Series, dataMap Dat
 		}
 		if len(totalsSerie.Datapoints) > 0 {
 			serie, totalsSerie = NormalizeTwo(dataMap, serie, totalsSerie)
-			serie = serie.Copy(pointSlicePool.Get().([]schema.Point))
+			serie = serie.Copy(pointSlicePool.Get())
 			for i := range serie.Datapoints {
 				serie.Datapoints[i].Val = computeAsPercent(serie.Datapoints[i].Val, totalsSerie.Datapoints[i].Val)
 			}
 		} else {
-			serie = serie.Copy(pointSlicePool.Get().([]schema.Point))
+			serie = serie.Copy(pointSlicePool.Get())
 			for i := range serie.Datapoints {
 				serie.Datapoints[i].Val = computeAsPercent(serie.Datapoints[i].Val, s.totalFloat)
 			}
@@ -284,7 +284,7 @@ func sumSeries(in []models.Series, dataMap DataMap) models.Series {
 	if len(in) == 1 {
 		return in[0]
 	}
-	out := pointSlicePool.Get().([]schema.Point)
+	out := pointSlicePool.Get()
 	crossSeriesSum(in, &out)
 	var queryPatts []string
 	var meta models.SeriesMeta

expr/func_constantline.go

@@ -36,7 +36,7 @@ func (s *FuncConstantLine) Context(context Context) Context {
 }
 
 func (s *FuncConstantLine) Exec(dataMap DataMap) ([]models.Series, error) {
-	out := pointSlicePool.Get().([]schema.Point)
+	out := pointSlicePool.Get()
 
 	out = append(out, schema.Point{Val: s.value, Ts: s.first})
 	diff := s.last - s.first

expr/func_countseries.go

@@ -5,7 +5,6 @@ import (
 	"strings"
 
 	"github.com/grafana/metrictank/api/models"
-	"github.com/grafana/metrictank/schema"
 )
 
 type FuncCountSeries struct {
@@ -38,7 +37,7 @@ func (s *FuncCountSeries) Exec(dataMap DataMap) ([]models.Series, error) {
 
 	cons, queryCons := summarizeCons(series)
 	name := fmt.Sprintf("countSeries(%s)", strings.Join(queryPatts, ","))
-	out := pointSlicePool.Get().([]schema.Point)
+	out := pointSlicePool.Get()
 
 	// note: if series have different intervals, we could try to be clever and pick the one with highest resolution
 	// as it's more likely to be useful when combined with other functions, but that's too much hassle

expr/func_derivative.go

@@ -6,7 +6,6 @@ import (
 
 	"github.com/grafana/metrictank/api/models"
 	"github.com/grafana/metrictank/consolidation"
-	"github.com/grafana/metrictank/schema"
 )
 
 type FuncDerivative struct {
@@ -39,7 +38,7 @@ func (s *FuncDerivative) Exec(dataMap DataMap) ([]models.Series, error) {
 		serie.QueryPatt = fmt.Sprintf("derivative(%s)", serie.QueryPatt)
 		serie.Consolidator = consolidation.None
 		serie.QueryCons = consolidation.None
-		out := pointSlicePool.Get().([]schema.Point)
+		out := pointSlicePool.Get()
 
 		prev := math.NaN()
 		for _, p := range serie.Datapoints {

expr/func_divideseries.go

@@ -65,7 +65,7 @@ func (s *FuncDivideSeries) Exec(dataMap DataMap) ([]models.Series, error) {
 	divisorsByRes := make(map[uint32]models.Series)
 	divisorsByRes[divisors[0].Interval] = divisors[0]
 	for _, dividend := range dividends {
-		out := pointSlicePool.Get().([]schema.Point)
+		out := pointSlicePool.Get()
 		divisor := divisors[0]
 		if dividend.Interval != divisors[0].Interval {
 			lcm := util.Lcm([]uint32{dividend.Interval, divisor.Interval})

expr/func_divideserieslists.go

@@ -54,7 +54,7 @@ func (s *FuncDivideSeriesLists) Exec(dataMap DataMap) ([]models.Series, error) {
 	for i := range dividends {
 		dividend, divisor := NormalizeTwo(dataMap, dividends[i], divisors[i])
 
-		out := pointSlicePool.Get().([]schema.Point)
+		out := pointSlicePool.Get()
 		for i := 0; i < len(dividend.Datapoints); i++ {
 			p := schema.Point{
 				Ts: dividend.Datapoints[i].Ts,

expr/func_groupbynodes.go

@@ -2,7 +2,6 @@ package expr
 
 import (
 	"github.com/grafana/metrictank/api/models"
-	"github.com/grafana/metrictank/schema"
 )
 
 type FuncGroupByNodes struct {
@@ -96,7 +95,7 @@ func (s *FuncGroupByNodes) Exec(dataMap DataMap) ([]models.Series, error) {
 		group.s = Normalize(dataMap, group.s)
 		outSeries.Interval = group.s[0].Interval
 		outSeries.SetTags()
-		outSeries.Datapoints = pointSlicePool.Get().([]schema.Point)
+		outSeries.Datapoints = pointSlicePool.Get()
 		aggFunc(group.s, &outSeries.Datapoints)
 		output = append(output, outSeries)
 	}

expr/func_groupbynodes_test.go

@@ -361,7 +361,7 @@ func benchmarkGroupByNodes(b *testing.B, numIn, numOut int) {
 		}
 
 		for _, serie := range results {
-			pointSlicePool.Put(serie.Datapoints[:0])
+			pointSlicePool.Put(serie.Datapoints)
 		}
 	}
 

expr/func_groupbytags.go

@@ -6,7 +6,6 @@ import (
 
 	"github.com/grafana/metrictank/api/models"
 	"github.com/grafana/metrictank/errors"
-	"github.com/grafana/metrictank/schema"
 )
 
 type FuncGroupByTags struct {
@@ -131,7 +130,7 @@ func (s *FuncGroupByTags) Exec(dataMap DataMap) ([]models.Series, error) {
 		}
 		newSeries.SetTags()
 
-		newSeries.Datapoints = pointSlicePool.Get().([]schema.Point)
+		newSeries.Datapoints = pointSlicePool.Get()
 		group.s = Normalize(dataMap, group.s)
 		aggFunc(group.s, &newSeries.Datapoints)
 		dataMap.Add(Req{}, newSeries)

expr/func_groupbytags_test.go

@@ -361,7 +361,7 @@ func benchmarkGroupByTags(b *testing.B, numInputSeries, numOutputSeries int) {
 
 		if true {
 			for _, serie := range results {
-				pointSlicePool.Put(serie.Datapoints[:0])
+				pointSlicePool.Put(serie.Datapoints)
 			}
 		}
 	}

expr/func_integral.go

@@ -6,7 +6,6 @@ import (
 
 	"github.com/grafana/metrictank/api/models"
 	"github.com/grafana/metrictank/consolidation"
-	"github.com/grafana/metrictank/schema"
 )
 
 type FuncIntegral struct {
@@ -42,7 +41,7 @@ func (s *FuncIntegral) Exec(dataMap DataMap) ([]models.Series, error) {
 
 		current := 0.0
 
-		out := pointSlicePool.Get().([]schema.Point)
+		out := pointSlicePool.Get()
 		for _, p := range serie.Datapoints {
 			if !math.IsNaN(p.Val) {
 				current += p.Val

expr/func_invert.go

@@ -41,7 +41,7 @@ func (s *FuncInvert) Exec(dataMap DataMap) ([]models.Series, error) {
 	}
 
 	for i, serie := range series {
-		out := pointSlicePool.Get().([]schema.Point)
+		out := pointSlicePool.Get()
 
 		for _, p := range serie.Datapoints {
 			out = append(out, schema.Point{Val: newVal(p.Val), Ts: p.Ts})

expr/func_isnonnull.go

@@ -5,7 +5,6 @@ import (
 	"math"
 
 	"github.com/grafana/metrictank/api/models"
-	"github.com/grafana/metrictank/schema"
 )
 
 type FuncIsNonNull struct {
@@ -37,7 +36,7 @@ func (s *FuncIsNonNull) Exec(dataMap DataMap) ([]models.Series, error) {
 		serie.QueryPatt = fmt.Sprintf("isNonNull(%s)", serie.QueryPatt)
 		serie.Tags = serie.CopyTagsWith("isNonNull", "1")
 
-		out := pointSlicePool.Get().([]schema.Point)
+		out := pointSlicePool.Get()
 		for _, p := range serie.Datapoints {
 			if math.IsNaN(p.Val) {
 				p.Val = 0

expr/func_keeplastvalue.go

@@ -5,7 +5,6 @@ import (
 	"math"
 
 	"github.com/grafana/metrictank/api/models"
-	"github.com/grafana/metrictank/schema"
 )
 
 type FuncKeepLastValue struct {
@@ -50,7 +49,7 @@ func (s *FuncKeepLastValue) Exec(dataMap DataMap) ([]models.Series, error) {
 	for _, serie := range series {
 		serie.Target = fmt.Sprintf("keepLastValue(%s)", serie.Target)
 		serie.QueryPatt = serie.Target
-		out := pointSlicePool.Get().([]schema.Point)
+		out := pointSlicePool.Get()
 
 		var consecutiveNaNs int
 		lastVal := math.NaN()

expr/func_minmax.go

@@ -52,7 +52,7 @@ func (s *FuncMinMax) Exec(dataMap DataMap) ([]models.Series, error) {
 	outputs := make([]models.Series, 0, len(series))
 
 	for _, serie := range series {
-		out := pointSlicePool.Get().([]schema.Point)
+		out := pointSlicePool.Get()
 
 		minVal := valOrDefault(batch.Min(serie.Datapoints), 0)
 		maxVal := valOrDefault(batch.Max(serie.Datapoints), 0)

expr/func_nonnegativederivative.go

@@ -6,7 +6,6 @@ import (
 
 	"github.com/grafana/metrictank/api/models"
 	"github.com/grafana/metrictank/consolidation"
-	"github.com/grafana/metrictank/schema"
 )
 
 type FuncNonNegativeDerivative struct {
@@ -40,7 +39,7 @@ func (s *FuncNonNegativeDerivative) Exec(dataMap DataMap) ([]models.Series, erro
 	outSeries := make([]models.Series, 0, len(series))
 
 	for _, serie := range series {
-		out := pointSlicePool.Get().([]schema.Point)
+		out := pointSlicePool.Get()
 
 		prev := math.NaN()
 		for _, p := range serie.Datapoints {

expr/func_offset.go

@@ -37,7 +37,7 @@ func (s *FuncOffset) Exec(dataMap DataMap) ([]models.Series, error) {
 
 	outSeries := make([]models.Series, 0, len(series))
 	for _, serie := range series {
-		out := pointSlicePool.Get().([]schema.Point)
+		out := pointSlicePool.Get()
 		for _, v := range serie.Datapoints {
 			out = append(out, schema.Point{Val: v.Val + s.factor, Ts: v.Ts})
 		}

expr/func_persecond.go

@@ -44,7 +44,7 @@ func (s *FuncPerSecond) Exec(dataMap DataMap) ([]models.Series, error) {
 
 	outSeries := make([]models.Series, 0, len(series))
 	for _, serie := range series {
-		out := pointSlicePool.Get().([]schema.Point)
+		out := pointSlicePool.Get()
 		for i, v := range serie.Datapoints {
 			out = append(out, schema.Point{Ts: v.Ts})
 			if i == 0 || math.IsNaN(v.Val) || math.IsNaN(serie.Datapoints[i-1].Val) {