Remove Quantile aggregation, DDSketch aggregator; add Exact timestamps (#1412)

* Remove quantile definition

* Complete removal of Quantile-related function

* Comment in selector/simple/simple.go

* Remove 'quantile' in mmsc

* Rename array->exact

* Update changelog

* Add PR number

* Rename exact benchmark

* New test for exact timestamps

* Add timestamp tests

* More test

* From feedback

* Apply suggestions from code review

Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>

* Samples->Points

* Rename

Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>

CHANGELOG.md

@@ -26,6 +26,9 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Improve span duration accuracy. (#1360)
 - Migrated CI/CD from CircleCI to GitHub Actions (#1382)
 - Remove duplicate checkout from GitHub Actions workflow (#1407)
+- Metric `array` aggregator renamed `exact` to match its `aggregation.Kind` (#1412)
+- Metric `exact` aggregator includes per-point timestamps (#1412)
+- Metric stdout exporter uses MinMaxSumCount aggregator for ValueRecorder instruments (#1412)
 - `NewExporter` from `exporters/otlp` now takes a `ProtocolDriver` as a parameter. (#1369)
 - Many OTLP Exporter options became gRPC ProtocolDriver options. (#1369)
 - Unify endpoint API that related to OTel exporter. (#1401)
@@ -36,6 +39,8 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 ### Removed
 
 - Remove `errUninitializedSpan` as its only usage is now obsolete. (#1360)
+- Remove Metric export functionality related to quantiles and summary data points: this is not specified (#1412)
+- Remove DDSketch metric aggregator; our intention is to re-introduce this as an option of the histogram aggregator after [new OTLP histogram data types](https://github.com/open-telemetry/opentelemetry-proto/pull/226) are released (#1412)
 
 ## [0.15.0] - 2020-12-10
 

example/basic/go.sum

@@ -1,13 +1,9 @@
-github.com/DataDog/sketches-go v0.0.1 h1:RtG+76WKgZuz6FIaGsjoPePmadDBkuD/KC6+ZWu78b8=
-github.com/DataDog/sketches-go v0.0.1/go.mod h1:Q5DbzQ+3AkgGwymQO7aZFNP7ns2lZKGtvRBzRXfdi60=
 github.com/benbjohnson/clock v1.0.3 h1:vkLuvpK4fmtSCuo60+yC63p7y0BmQ8gm5ZXGuBCJyXg=
 github.com/benbjohnson/clock v1.0.3/go.mod h1:bGMdMPoPVvcYyt1gHDf4J2KE153Yf9BuiUKYMaxlTDM=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/gofuzz v1.1.0 h1:Hsa8mG0dQ46ij8Sl2AYJDUv1oA9/d6Vk+3LG99Oe02g=
-github.com/google/gofuzz v1.1.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=

example/basic/main.go

@@ -40,7 +40,6 @@ var (
 
 func main() {
 	exporter, err := stdout.NewExporter([]stdout.Option{
-		stdout.WithQuantiles([]float64{0.5, 0.9, 0.99}),
 		stdout.WithPrettyPrint(),
 	}...)
 	if err != nil {

example/jaeger/go.sum

@@ -34,7 +34,6 @@ cloud.google.com/go/storage v1.10.0/go.mod h1:FLPqc6j+Ki4BU591ie1oL6qBQGu2Bl/tZ9
 dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
-github.com/DataDog/sketches-go v0.0.1/go.mod h1:Q5DbzQ+3AkgGwymQO7aZFNP7ns2lZKGtvRBzRXfdi60=
 github.com/apache/thrift v0.13.0 h1:5hryIiq9gtn+MiLVn0wP37kb/uTeRZgN08WoCsAhIhI=
 github.com/apache/thrift v0.13.0/go.mod h1:cp2SuWMxlEZw2r+iP2GNCdIi4C1qmUzdZFSVb+bacwQ=
 github.com/benbjohnson/clock v1.0.3/go.mod h1:bGMdMPoPVvcYyt1gHDf4J2KE153Yf9BuiUKYMaxlTDM=
@@ -93,7 +92,6 @@ github.com/google/go-cmp v0.5.2 h1:X2ev0eStA3AbceY54o37/0PQ/UWqKEiiO2dKL5OPaFM=
 github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/gofuzz v1.1.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/martian v2.1.0+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXiIaQGbYVAs8BPL6v8lEs=
 github.com/google/martian/v3 v3.0.0/go.mod h1:y5Zk1BBys9G+gd6Jrk0W3cC1+ELVxBWuIGO+w/tUAp0=
 github.com/google/martian/v3 v3.1.0/go.mod h1:y5Zk1BBys9G+gd6Jrk0W3cC1+ELVxBWuIGO+w/tUAp0=

example/namedtracer/go.sum

@@ -1,13 +1,9 @@
-github.com/DataDog/sketches-go v0.0.1 h1:RtG+76WKgZuz6FIaGsjoPePmadDBkuD/KC6+ZWu78b8=
-github.com/DataDog/sketches-go v0.0.1/go.mod h1:Q5DbzQ+3AkgGwymQO7aZFNP7ns2lZKGtvRBzRXfdi60=
 github.com/benbjohnson/clock v1.0.3 h1:vkLuvpK4fmtSCuo60+yC63p7y0BmQ8gm5ZXGuBCJyXg=
 github.com/benbjohnson/clock v1.0.3/go.mod h1:bGMdMPoPVvcYyt1gHDf4J2KE153Yf9BuiUKYMaxlTDM=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/gofuzz v1.1.0 h1:Hsa8mG0dQ46ij8Sl2AYJDUv1oA9/d6Vk+3LG99Oe02g=
-github.com/google/gofuzz v1.1.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=

example/opencensus/go.sum

@@ -1,7 +1,5 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/DataDog/sketches-go v0.0.1 h1:RtG+76WKgZuz6FIaGsjoPePmadDBkuD/KC6+ZWu78b8=
-github.com/DataDog/sketches-go v0.0.1/go.mod h1:Q5DbzQ+3AkgGwymQO7aZFNP7ns2lZKGtvRBzRXfdi60=
 github.com/benbjohnson/clock v1.0.3 h1:vkLuvpK4fmtSCuo60+yC63p7y0BmQ8gm5ZXGuBCJyXg=
 github.com/benbjohnson/clock v1.0.3/go.mod h1:bGMdMPoPVvcYyt1gHDf4J2KE153Yf9BuiUKYMaxlTDM=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
@@ -16,8 +14,6 @@ github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5y
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/gofuzz v1.1.0 h1:Hsa8mG0dQ46ij8Sl2AYJDUv1oA9/d6Vk+3LG99Oe02g=
-github.com/google/gofuzz v1.1.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=

example/otel-collector/go.sum

@@ -1,7 +1,5 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/DataDog/sketches-go v0.0.1 h1:RtG+76WKgZuz6FIaGsjoPePmadDBkuD/KC6+ZWu78b8=
-github.com/DataDog/sketches-go v0.0.1/go.mod h1:Q5DbzQ+3AkgGwymQO7aZFNP7ns2lZKGtvRBzRXfdi60=
 github.com/benbjohnson/clock v1.0.3 h1:vkLuvpK4fmtSCuo60+yC63p7y0BmQ8gm5ZXGuBCJyXg=
 github.com/benbjohnson/clock v1.0.3/go.mod h1:bGMdMPoPVvcYyt1gHDf4J2KE153Yf9BuiUKYMaxlTDM=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
@@ -34,8 +32,6 @@ github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/google/go-cmp v0.5.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/gofuzz v1.1.0 h1:Hsa8mG0dQ46ij8Sl2AYJDUv1oA9/d6Vk+3LG99Oe02g=
-github.com/google/gofuzz v1.1.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/uuid v1.1.2/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/kisielk/errcheck v1.2.0/go.mod h1:/BMXB+zMLi60iA8Vv6Ksmxu/1UDYcXs4uQLJ+jE2L00=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=

example/prometheus/go.sum

@@ -1,8 +1,6 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/DataDog/sketches-go v0.0.1 h1:RtG+76WKgZuz6FIaGsjoPePmadDBkuD/KC6+ZWu78b8=
-github.com/DataDog/sketches-go v0.0.1/go.mod h1:Q5DbzQ+3AkgGwymQO7aZFNP7ns2lZKGtvRBzRXfdi60=
 github.com/Knetic/govaluate v3.0.1-0.20171022003610-9aa49832a739+incompatible/go.mod h1:r7JcOSlj0wfOMncg0iLm8Leh48TZaKVeNIfJntJ2wa0=
 github.com/Shopify/sarama v1.19.0/go.mod h1:FVkBWblsNy7DGZRfXLU0O9RCGt5g3g3yEuWXgklEdEo=
 github.com/Shopify/toxiproxy v2.1.4+incompatible/go.mod h1:OXgGpZ6Cli1/URJOF1DMxUHB2q5Ap20/P/eIdh4G0pI=
@@ -98,8 +96,6 @@ github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
-github.com/google/gofuzz v1.1.0 h1:Hsa8mG0dQ46ij8Sl2AYJDUv1oA9/d6Vk+3LG99Oe02g=
-github.com/google/gofuzz v1.1.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm40UhjYkI=
 github.com/google/uuid v1.0.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=

example/zipkin/go.sum

@@ -1,6 +1,5 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/DataDog/sketches-go v0.0.1/go.mod h1:Q5DbzQ+3AkgGwymQO7aZFNP7ns2lZKGtvRBzRXfdi60=
 github.com/Shopify/sarama v1.19.0/go.mod h1:FVkBWblsNy7DGZRfXLU0O9RCGt5g3g3yEuWXgklEdEo=
 github.com/Shopify/toxiproxy v2.1.4+incompatible/go.mod h1:OXgGpZ6Cli1/URJOF1DMxUHB2q5Ap20/P/eIdh4G0pI=
 github.com/benbjohnson/clock v1.0.3/go.mod h1:bGMdMPoPVvcYyt1gHDf4J2KE153Yf9BuiUKYMaxlTDM=
@@ -40,7 +39,6 @@ github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/google/go-cmp v0.5.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/gofuzz v1.1.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/gorilla/context v1.1.1/go.mod h1:kBGZzfjB9CEq2AlWe17Uuf7NDRt0dE0s8S51q0aT7Yg=
 github.com/gorilla/mux v1.6.2/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=

exporters/metric/prometheus/go.sum

@@ -1,8 +1,6 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/DataDog/sketches-go v0.0.1 h1:RtG+76WKgZuz6FIaGsjoPePmadDBkuD/KC6+ZWu78b8=
-github.com/DataDog/sketches-go v0.0.1/go.mod h1:Q5DbzQ+3AkgGwymQO7aZFNP7ns2lZKGtvRBzRXfdi60=
 github.com/Knetic/govaluate v3.0.1-0.20171022003610-9aa49832a739+incompatible/go.mod h1:r7JcOSlj0wfOMncg0iLm8Leh48TZaKVeNIfJntJ2wa0=
 github.com/Shopify/sarama v1.19.0/go.mod h1:FVkBWblsNy7DGZRfXLU0O9RCGt5g3g3yEuWXgklEdEo=
 github.com/Shopify/toxiproxy v2.1.4+incompatible/go.mod h1:OXgGpZ6Cli1/URJOF1DMxUHB2q5Ap20/P/eIdh4G0pI=
@@ -99,8 +97,6 @@ github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
-github.com/google/gofuzz v1.1.0 h1:Hsa8mG0dQ46ij8Sl2AYJDUv1oA9/d6Vk+3LG99Oe02g=
-github.com/google/gofuzz v1.1.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm40UhjYkI=
 github.com/google/uuid v1.0.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=

exporters/metric/prometheus/prometheus.go

@@ -14,6 +14,9 @@
 
 package prometheus // import "go.opentelemetry.io/otel/exporters/metric/prometheus"
 
+// Note that this package does not support a way to export Prometheus
+// Summary data points, removed in PR#1412.
+
 import (
 	"context"
 	"fmt"
@@ -50,10 +53,13 @@ type Exporter struct {
 	lock       sync.RWMutex
 	controller *pull.Controller
 
-	defaultSummaryQuantiles    []float64
 	defaultHistogramBoundaries []float64
 }
 
+// ErrUnsupportedAggregator is returned for unrepresentable aggregator
+// types (e.g., exact).
+var ErrUnsupportedAggregator = fmt.Errorf("unsupported aggregator type")
+
 var _ http.Handler = &Exporter{}
 
 // Config is a set of configs for the tally reporter.
@@ -76,10 +82,6 @@ type Config struct {
 	// If not specified the Registry will be used as default.
 	Gatherer prometheus.Gatherer
 
-	// DefaultSummaryQuantiles is the default summary quantiles
-	// to use. Use nil to specify the system-default summary quantiles.
-	DefaultSummaryQuantiles []float64
-
 	// DefaultHistogramBoundaries defines the default histogram bucket
 	// boundaries.
 	DefaultHistogramBoundaries []float64
@@ -104,7 +106,6 @@ func NewExportPipeline(config Config, options ...pull.Option) (*Exporter, error)
 		handler:                    promhttp.HandlerFor(config.Gatherer, promhttp.HandlerOpts{}),
 		registerer:                 config.Registerer,
 		gatherer:                   config.Gatherer,
-		defaultSummaryQuantiles:    config.DefaultSummaryQuantiles,
 		defaultHistogramBoundaries: config.DefaultHistogramBoundaries,
 	}
 
@@ -167,15 +168,12 @@ func (e *Exporter) Controller() *pull.Controller {
 	return e.controller
 }
 
+// ExportKindFor implements ExportKindSelector.
 func (e *Exporter) ExportKindFor(desc *metric.Descriptor, kind aggregation.Kind) export.ExportKind {
-	// NOTE: Summary values should use Delta aggregation, then be
-	// combined into a sliding window, see the TODO below.
-	// NOTE: Prometheus also supports a "GaugeDelta" exposition format,
-	// which is expressed as a delta histogram.  Need to understand if this
-	// should be a default behavior for ValueRecorder/ValueObserver.
 	return export.CumulativeExportKindSelector().ExportKindFor(desc, kind)
 }
 
+// ServeHTTP implements http.Handler.
 func (e *Exporter) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	e.handler.ServeHTTP(w, r)
 }
@@ -187,6 +185,7 @@ type collector struct {
 
 var _ prometheus.Collector = (*collector)(nil)
 
+// Describe implements prometheus.Collector.
 func (c *collector) Describe(ch chan<- *prometheus.Desc) {
 	c.exp.lock.RLock()
 	defer c.exp.lock.RUnlock()
@@ -226,18 +225,6 @@ func (c *collector) Collect(ch chan<- prometheus.Metric) {
 			if err := c.exportHistogram(ch, hist, numberKind, desc, labels); err != nil {
 				return fmt.Errorf("exporting histogram: %w", err)
 			}
-		} else if dist, ok := agg.(aggregation.Distribution); ok {
-			// TODO: summaries values are never being resetted.
-			//  As measurements are recorded, new records starts to have less impact on these summaries.
-			//  We should implement an solution that is similar to the Prometheus Clients
-			//  using a rolling window for summaries could be a solution.
-			//
-			//  References:
-			// 	https://www.robustperception.io/how-does-a-prometheus-summary-work
-			//  https://github.com/prometheus/client_golang/blob/fa4aa9000d2863904891d193dea354d23f3d712a/prometheus/summary.go#L135
-			if err := c.exportSummary(ch, dist, numberKind, desc, labels); err != nil {
-				return fmt.Errorf("exporting summary: %w", err)
-			}
 		} else if sum, ok := agg.(aggregation.Sum); ok && instrumentKind.Monotonic() {
 			if err := c.exportMonotonicCounter(ch, sum, numberKind, desc, labels); err != nil {
 				return fmt.Errorf("exporting monotonic counter: %w", err)
@@ -250,6 +237,8 @@ func (c *collector) Collect(ch chan<- prometheus.Metric) {
 			if err := c.exportLastValue(ch, lastValue, numberKind, desc, labels); err != nil {
 				return fmt.Errorf("exporting last value: %w", err)
 			}
+		} else {
+			return fmt.Errorf("%w: %s", ErrUnsupportedAggregator, agg.Kind())
 		}
 		return nil
 	})
@@ -303,33 +292,6 @@ func (c *collector) exportMonotonicCounter(ch chan<- prometheus.Metric, sum aggr
 	return nil
 }
 
-func (c *collector) exportSummary(ch chan<- prometheus.Metric, dist aggregation.Distribution, kind number.Kind, desc *prometheus.Desc, labels []string) error {
-	count, err := dist.Count()
-	if err != nil {
-		return fmt.Errorf("error retrieving count: %w", err)
-	}
-
-	var sum number.Number
-	sum, err = dist.Sum()
-	if err != nil {
-		return fmt.Errorf("error retrieving distribution sum: %w", err)
-	}
-
-	quantiles := make(map[float64]float64)
-	for _, quantile := range c.exp.defaultSummaryQuantiles {
-		q, _ := dist.Quantile(quantile)
-		quantiles[quantile] = q.CoerceToFloat64(kind)
-	}
-
-	m, err := prometheus.NewConstSummary(desc, uint64(count), sum.CoerceToFloat64(kind), quantiles, labels...)
-	if err != nil {
-		return fmt.Errorf("error creating constant summary: %w", err)
-	}
-
-	ch <- m
-	return nil
-}
-
 func (c *collector) exportHistogram(ch chan<- prometheus.Metric, hist aggregation.Histogram, kind number.Kind, desc *prometheus.Desc, labels []string) error {
 	buckets, err := hist.Histogram()
 	if err != nil {

exporters/otlp/go.sum

@@ -1,7 +1,5 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/DataDog/sketches-go v0.0.1 h1:RtG+76WKgZuz6FIaGsjoPePmadDBkuD/KC6+ZWu78b8=
-github.com/DataDog/sketches-go v0.0.1/go.mod h1:Q5DbzQ+3AkgGwymQO7aZFNP7ns2lZKGtvRBzRXfdi60=
 github.com/benbjohnson/clock v1.0.3 h1:vkLuvpK4fmtSCuo60+yC63p7y0BmQ8gm5ZXGuBCJyXg=
 github.com/benbjohnson/clock v1.0.3/go.mod h1:bGMdMPoPVvcYyt1gHDf4J2KE153Yf9BuiUKYMaxlTDM=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
@@ -34,8 +32,6 @@ github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/google/go-cmp v0.5.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/gofuzz v1.1.0 h1:Hsa8mG0dQ46ij8Sl2AYJDUv1oA9/d6Vk+3LG99Oe02g=
-github.com/google/gofuzz v1.1.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/uuid v1.1.2/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/kisielk/errcheck v1.2.0/go.mod h1:/BMXB+zMLi60iA8Vv6Ksmxu/1UDYcXs4uQLJ+jE2L00=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=

exporters/otlp/internal/transform/metric.go

@@ -306,7 +306,7 @@ func Record(exportSelector export.ExportKindSelector, r export.Record) (*metricp
 	}
 }
 
-func gaugeArray(record export.Record, points []number.Number) (*metricpb.Metric, error) {
+func gaugeArray(record export.Record, points []aggregation.Point) (*metricpb.Metric, error) {
 	desc := record.Descriptor()
 	m := &metricpb.Metric{
 		Name:        desc.Name(),
@@ -314,15 +314,15 @@ func gaugeArray(record export.Record, points []number.Number) (*metricpb.Metric,
 		Unit:        string(desc.Unit()),
 	}
 
-	switch n := desc.NumberKind(); n {
+	switch nk := desc.NumberKind(); nk {
 	case number.Int64Kind:
 		var pts []*metricpb.IntDataPoint
-		for _, p := range points {
+		for _, s := range points {
 			pts = append(pts, &metricpb.IntDataPoint{
 				Labels:            nil,
 				StartTimeUnixNano: toNanos(record.StartTime()),
 				TimeUnixNano:      toNanos(record.EndTime()),
-				Value:             p.CoerceToInt64(n),
+				Value:             s.Number.CoerceToInt64(nk),
 			})
 		}
 		m.Data = &metricpb.Metric_IntGauge{
@@ -333,12 +333,12 @@ func gaugeArray(record export.Record, points []number.Number) (*metricpb.Metric,
 
 	case number.Float64Kind:
 		var pts []*metricpb.DoubleDataPoint
-		for _, p := range points {
+		for _, s := range points {
 			pts = append(pts, &metricpb.DoubleDataPoint{
 				Labels:            nil,
 				StartTimeUnixNano: toNanos(record.StartTime()),
 				TimeUnixNano:      toNanos(record.EndTime()),
-				Value:             p.CoerceToFloat64(n),
+				Value:             s.Number.CoerceToFloat64(nk),
 			})
 		}
 		m.Data = &metricpb.Metric_DoubleGauge{
@@ -348,7 +348,7 @@ func gaugeArray(record export.Record, points []number.Number) (*metricpb.Metric,
 		}
 
 	default:
-		return nil, fmt.Errorf("%w: %v", ErrUnknownValueType, n)
+		return nil, fmt.Errorf("%w: %v", ErrUnknownValueType, nk)
 	}
 
 	return m, nil

exporters/otlp/internal/transform/metric_test.go

@@ -32,7 +32,7 @@ import (
 	export "go.opentelemetry.io/otel/sdk/export/metric"
 	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
 	"go.opentelemetry.io/otel/sdk/export/metric/metrictest"
-	arrAgg "go.opentelemetry.io/otel/sdk/metric/aggregator/array"
+	arrAgg "go.opentelemetry.io/otel/sdk/metric/aggregator/exact"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/lastvalue"
 	lvAgg "go.opentelemetry.io/otel/sdk/metric/aggregator/lastvalue"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/minmaxsumcount"

exporters/stdout/config.go

@@ -19,14 +19,12 @@ import (
 	"os"
 
 	"go.opentelemetry.io/otel/label"
-	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
 )
 
 var (
 	defaultWriter              = os.Stdout
 	defaultPrettyPrint         = false
 	defaultTimestamps          = true
-	defaultQuantiles           = []float64{0.5, 0.9, 0.99}
 	defaultLabelEncoder        = label.DefaultEncoder()
 	defaultDisableTraceExport  = false
 	defaultDisableMetricExport = false
@@ -45,15 +43,6 @@ type Config struct {
 	// true.
 	Timestamps bool
 
-	// Quantiles are the desired aggregation quantiles for distribution
-	// summaries, used when the configured aggregator supports
-	// quantiles.
-	//
-	// Note: this exporter is meant as a demonstration; a real
-	// exporter may wish to configure quantiles on a per-metric
-	// basis.
-	Quantiles []float64
-
 	// LabelEncoder encodes the labels.
 	LabelEncoder label.Encoder
 
@@ -70,7 +59,6 @@ func NewConfig(options ...Option) (Config, error) {
 		Writer:              defaultWriter,
 		PrettyPrint:         defaultPrettyPrint,
 		Timestamps:          defaultTimestamps,
-		Quantiles:           defaultQuantiles,
 		LabelEncoder:        defaultLabelEncoder,
 		DisableTraceExport:  defaultDisableTraceExport,
 		DisableMetricExport: defaultDisableMetricExport,
@@ -79,11 +67,6 @@ func NewConfig(options ...Option) (Config, error) {
 		opt.Apply(&config)
 
 	}
-	for _, q := range config.Quantiles {
-		if q < 0 || q > 1 {
-			return config, aggregation.ErrInvalidQuantile
-		}
-	}
 	return config, nil
 }
 
@@ -128,17 +111,6 @@ func (o timestampsOption) Apply(config *Config) {
 	config.Timestamps = bool(o)
 }
 
-// WithQuantiles sets the quantile values to export.
-func WithQuantiles(quantiles []float64) Option {
-	return quantilesOption(quantiles)
-}
-
-type quantilesOption []float64
-
-func (o quantilesOption) Apply(config *Config) {
-	config.Quantiles = []float64(o)
-}
-
 // WithLabelEncoder sets the label encoder used in export.
 func WithLabelEncoder(enc label.Encoder) Option {
 	return labelEncoderOption{enc}

exporters/stdout/example_test.go

@@ -77,7 +77,6 @@ func multiply(ctx context.Context, x, y int64) int64 {
 
 func Example() {
 	exportOpts := []stdout.Option{
-		stdout.WithQuantiles([]float64{0.5}),
 		stdout.WithPrettyPrint(),
 	}
 	// Registers both a trace and meter Provider globally.

exporters/stdout/exporter.go

@@ -59,7 +59,7 @@ func NewExportPipeline(exportOpts []Option, pushOpts []push.Option) (trace.Trace
 	tp := sdktrace.NewTracerProvider(sdktrace.WithBatcher(exporter))
 	pusher := push.New(
 		basic.New(
-			simple.NewWithExactDistribution(),
+			simple.NewWithInexpensiveDistribution(),
 			exporter,
 		),
 		exporter,

exporters/stdout/go.sum

@@ -1,13 +1,9 @@
-github.com/DataDog/sketches-go v0.0.1 h1:RtG+76WKgZuz6FIaGsjoPePmadDBkuD/KC6+ZWu78b8=
-github.com/DataDog/sketches-go v0.0.1/go.mod h1:Q5DbzQ+3AkgGwymQO7aZFNP7ns2lZKGtvRBzRXfdi60=
 github.com/benbjohnson/clock v1.0.3 h1:vkLuvpK4fmtSCuo60+yC63p7y0BmQ8gm5ZXGuBCJyXg=
 github.com/benbjohnson/clock v1.0.3/go.mod h1:bGMdMPoPVvcYyt1gHDf4J2KE153Yf9BuiUKYMaxlTDM=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/gofuzz v1.1.0 h1:Hsa8mG0dQ46ij8Sl2AYJDUv1oA9/d6Vk+3LG99Oe02g=
-github.com/google/gofuzz v1.1.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=

exporters/stdout/metric.go

@@ -41,17 +41,10 @@ type line struct {
 	Count     interface{} `json:"Count,omitempty"`
 	LastValue interface{} `json:"Last,omitempty"`
 
-	Quantiles []quantile `json:"Quantiles,omitempty"`
-
 	// Note: this is a pointer because omitempty doesn't work when time.IsZero()
 	Timestamp *time.Time `json:"Timestamp,omitempty"`
 }
 
-type quantile struct {
-	Quantile interface{} `json:"Quantile"`
-	Value    interface{} `json:"Value"`
-}
-
 func (e *metricExporter) ExportKindFor(desc *metric.Descriptor, kind aggregation.Kind) exportmetric.ExportKind {
 	return exportmetric.StatelessExportKindSelector().ExportKindFor(desc, kind)
 }
@@ -106,22 +99,6 @@ func (e *metricExporter) Export(_ context.Context, checkpointSet exportmetric.Ch
 				return err
 			}
 			expose.Min = min.AsInterface(kind)
-
-			if dist, ok := agg.(aggregation.Distribution); ok && len(e.config.Quantiles) != 0 {
-				summary := make([]quantile, len(e.config.Quantiles))
-				expose.Quantiles = summary
-
-				for i, q := range e.config.Quantiles {
-					value, err := dist.Quantile(q)
-					if err != nil {
-						return err
-					}
-					summary[i] = quantile{
-						Quantile: q,
-						Value:    value.AsInterface(kind),
-					}
-				}
-			}
 		} else if lv, ok := agg.(aggregation.LastValue); ok {
 			value, timestamp, err := lv.LastValue()
 			if err != nil {

exporters/stdout/metric_test.go

@@ -31,11 +31,8 @@ import (
 	"go.opentelemetry.io/otel/metric"
 	"go.opentelemetry.io/otel/metric/number"
 	export "go.opentelemetry.io/otel/sdk/export/metric"
-	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
 	"go.opentelemetry.io/otel/sdk/export/metric/metrictest"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/aggregatortest"
-	"go.opentelemetry.io/otel/sdk/metric/aggregator/array"
-	"go.opentelemetry.io/otel/sdk/metric/aggregator/ddsketch"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/lastvalue"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/minmaxsumcount"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/sum"
@@ -78,14 +75,6 @@ func (fix testFixture) Export(checkpointSet export.CheckpointSet) {
 	}
 }
 
-func TestStdoutInvalidQuantile(t *testing.T) {
-	_, err := stdout.NewExporter(
-		stdout.WithQuantiles([]float64{1.1, 0.9}),
-	)
-	require.Error(t, err, "Invalid quantile error expected")
-	require.Equal(t, aggregation.ErrInvalidQuantile, err)
-}
-
 func TestStdoutTimestamp(t *testing.T) {
 	var buf bytes.Buffer
 	exporter, err := stdout.NewExporter(
@@ -197,7 +186,7 @@ func TestStdoutValueRecorderFormat(t *testing.T) {
 	checkpointSet := metrictest.NewCheckpointSet(testResource)
 
 	desc := metric.NewDescriptor("test.name", metric.ValueRecorderInstrumentKind, number.Float64Kind)
-	aagg, ckpt := metrictest.Unslice2(array.New(2))
+	aagg, ckpt := metrictest.Unslice2(minmaxsumcount.New(2, &desc))
 
 	for i := 0; i < 1000; i++ {
 		aggregatortest.CheckedUpdate(fix.t, aagg, number.NewFloat64Number(float64(i)+0.5), &desc)
@@ -215,21 +204,7 @@ func TestStdoutValueRecorderFormat(t *testing.T) {
 		"Min": 0.5,
 		"Max": 999.5,
 		"Sum": 500000,
-		"Count": 1000,
+		"Count": 1000
-		"Quantiles": [
-			{
-				"Quantile": 0.5,
-				"Value": 500.5
-			},
-			{
-				"Quantile": 0.9,
-				"Value": 900.5
-			},
-			{
-				"Quantile": 0.99,
-				"Value": 990.5
-			}
-		]
 	}
 ]`, fix.Output())
 }
@@ -255,7 +230,7 @@ func TestStdoutNoData(t *testing.T) {
 		})
 	}
 
-	runTwoAggs(metrictest.Unslice2(ddsketch.New(2, &desc, ddsketch.NewDefaultConfig())))
+	runTwoAggs(metrictest.Unslice2(lastvalue.New(2)))
 	runTwoAggs(metrictest.Unslice2(minmaxsumcount.New(2, &desc)))
 }
 

exporters/trace/jaeger/go.sum

@@ -34,7 +34,6 @@ cloud.google.com/go/storage v1.10.0/go.mod h1:FLPqc6j+Ki4BU591ie1oL6qBQGu2Bl/tZ9
 dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
-github.com/DataDog/sketches-go v0.0.1/go.mod h1:Q5DbzQ+3AkgGwymQO7aZFNP7ns2lZKGtvRBzRXfdi60=
 github.com/apache/thrift v0.13.0 h1:5hryIiq9gtn+MiLVn0wP37kb/uTeRZgN08WoCsAhIhI=
 github.com/apache/thrift v0.13.0/go.mod h1:cp2SuWMxlEZw2r+iP2GNCdIi4C1qmUzdZFSVb+bacwQ=
 github.com/benbjohnson/clock v1.0.3/go.mod h1:bGMdMPoPVvcYyt1gHDf4J2KE153Yf9BuiUKYMaxlTDM=
@@ -93,7 +92,6 @@ github.com/google/go-cmp v0.5.2 h1:X2ev0eStA3AbceY54o37/0PQ/UWqKEiiO2dKL5OPaFM=
 github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/gofuzz v1.1.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/martian v2.1.0+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXiIaQGbYVAs8BPL6v8lEs=
 github.com/google/martian/v3 v3.0.0/go.mod h1:y5Zk1BBys9G+gd6Jrk0W3cC1+ELVxBWuIGO+w/tUAp0=
 github.com/google/martian/v3 v3.1.0/go.mod h1:y5Zk1BBys9G+gd6Jrk0W3cC1+ELVxBWuIGO+w/tUAp0=

exporters/trace/zipkin/go.sum

@@ -1,6 +1,5 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/DataDog/sketches-go v0.0.1/go.mod h1:Q5DbzQ+3AkgGwymQO7aZFNP7ns2lZKGtvRBzRXfdi60=
 github.com/Shopify/sarama v1.19.0/go.mod h1:FVkBWblsNy7DGZRfXLU0O9RCGt5g3g3yEuWXgklEdEo=
 github.com/Shopify/toxiproxy v2.1.4+incompatible/go.mod h1:OXgGpZ6Cli1/URJOF1DMxUHB2q5Ap20/P/eIdh4G0pI=
 github.com/benbjohnson/clock v1.0.3/go.mod h1:bGMdMPoPVvcYyt1gHDf4J2KE153Yf9BuiUKYMaxlTDM=
@@ -40,7 +39,6 @@ github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/google/go-cmp v0.5.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/gofuzz v1.1.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/gorilla/context v1.1.1/go.mod h1:kBGZzfjB9CEq2AlWe17Uuf7NDRt0dE0s8S51q0aT7Yg=
 github.com/gorilla/mux v1.6.2/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=

sdk/export/metric/aggregation/aggregation.go

@@ -58,23 +58,26 @@ type (
 		Max() (number.Number, error)
 	}
 
-	// Quantile returns an exact or estimated quantile over the
-	// set of values that were aggregated.
-	Quantile interface {
-		Aggregation
-		Quantile(float64) (number.Number, error)
-	}
-
 	// LastValue returns the latest value that was aggregated.
 	LastValue interface {
 		Aggregation
 		LastValue() (number.Number, time.Time, error)
 	}
 
-	// Points returns the raw set of values that were aggregated.
+	// Points returns the raw values that were aggregated.
 	Points interface {
 		Aggregation
-		Points() ([]number.Number, error)
+
+		// Points returns points in the order they were
+		// recorded.  Points are approximately ordered by
+		// timestamp, but this is not guaranteed.
+		Points() ([]Point, error)
+	}
+
+	// Point is a raw data point, consisting of a number and value.
+	Point struct {
+		number.Number
+		time.Time
 	}
 
 	// Buckets represents histogram buckets boundaries and counts.
@@ -106,17 +109,6 @@ type (
 		Sum() (number.Number, error)
 		Count() (uint64, error)
 	}
-
-	// Distribution supports the Min, Max, Sum, Count, and Quantile
-	// interfaces.
-	Distribution interface {
-		Aggregation
-		Min() (number.Number, error)
-		Max() (number.Number, error)
-		Sum() (number.Number, error)
-		Count() (uint64, error)
-		Quantile(float64) (number.Number, error)
-	}
 )
 
 type (
@@ -141,12 +133,10 @@ const (
 	MinMaxSumCountKind Kind = "MinMaxSumCount"
 	HistogramKind      Kind = "Histogram"
 	LastValueKind      Kind = "Lastvalue"
-	SketchKind         Kind = "Sketch"
 	ExactKind          Kind = "Exact"
 )
 
 var (
-	ErrInvalidQuantile  = fmt.Errorf("the requested quantile is out of range")
 	ErrNegativeInput    = fmt.Errorf("negative value is out of range for this instrument")
 	ErrNaNInput         = fmt.Errorf("NaN value is an invalid input")
 	ErrInconsistentType = fmt.Errorf("inconsistent aggregator types")

sdk/go.mod

@@ -5,10 +5,8 @@ go 1.14
 replace go.opentelemetry.io/otel => ../
 
 require (
-	github.com/DataDog/sketches-go v0.0.1
 	github.com/benbjohnson/clock v1.0.3
 	github.com/google/go-cmp v0.5.4
-	github.com/google/gofuzz v1.1.0 // indirect
 	github.com/stretchr/testify v1.6.1
 	go.opentelemetry.io/otel v0.15.0
 )

sdk/go.sum

@@ -1,13 +1,9 @@
-github.com/DataDog/sketches-go v0.0.1 h1:RtG+76WKgZuz6FIaGsjoPePmadDBkuD/KC6+ZWu78b8=
-github.com/DataDog/sketches-go v0.0.1/go.mod h1:Q5DbzQ+3AkgGwymQO7aZFNP7ns2lZKGtvRBzRXfdi60=
 github.com/benbjohnson/clock v1.0.3 h1:vkLuvpK4fmtSCuo60+yC63p7y0BmQ8gm5ZXGuBCJyXg=
 github.com/benbjohnson/clock v1.0.3/go.mod h1:bGMdMPoPVvcYyt1gHDf4J2KE153Yf9BuiUKYMaxlTDM=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/gofuzz v1.1.0 h1:Hsa8mG0dQ46ij8Sl2AYJDUv1oA9/d6Vk+3LG99Oe02g=
-github.com/google/gofuzz v1.1.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=

sdk/metric/aggregator/aggregatortest/test.go

@@ -92,8 +92,6 @@ func TestMain(m *testing.M) {
 	os.Exit(m.Run())
 }
 
-// TODO: Expose Numbers in api/metric for sorting support
-
 type Numbers struct {
 	// numbers has to be aligned for 64-bit atomic operations.
 	numbers []number.Number
@@ -146,16 +144,6 @@ func (n *Numbers) Max() number.Number {
 	return n.numbers[len(n.numbers)-1]
 }
 
-// Median() is an alias for Quantile(0.5).
-func (n *Numbers) Median() number.Number {
-	// Note that len(n.numbers) is 1 greater than the max element
-	// index, so dividing by two rounds up.  This gives the
-	// intended definition for Quantile() in tests, which is to
-	// return the smallest element that is at or above the
-	// specified quantile.
-	return n.numbers[len(n.numbers)/2]
-}
-
 func (n *Numbers) Points() []number.Number {
 	return n.numbers
 }

sdk/metric/aggregator/array/array.go

@@ -1,219 +0,0 @@
-// Copyright The OpenTelemetry Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package array // import "go.opentelemetry.io/otel/sdk/metric/aggregator/array"
-
-import (
-	"context"
-	"math"
-	"sort"
-	"sync"
-	"unsafe"
-
-	"go.opentelemetry.io/otel/metric"
-	"go.opentelemetry.io/otel/metric/number"
-	export "go.opentelemetry.io/otel/sdk/export/metric"
-	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
-	"go.opentelemetry.io/otel/sdk/metric/aggregator"
-)
-
-type (
-	// Aggregator aggregates events that form a distribution, keeping
-	// an array with the exact set of values.
-	Aggregator struct {
-		lock   sync.Mutex
-		sum    number.Number
-		points points
-	}
-
-	points []number.Number
-)
-
-var _ export.Aggregator = &Aggregator{}
-var _ aggregation.MinMaxSumCount = &Aggregator{}
-var _ aggregation.Distribution = &Aggregator{}
-var _ aggregation.Points = &Aggregator{}
-
-// New returns a new array aggregator, which aggregates recorded
-// measurements by storing them in an array.  This type uses a mutex
-// for Update() and SynchronizedMove() concurrency.
-func New(cnt int) []Aggregator {
-	return make([]Aggregator, cnt)
-}
-
-// Aggregation returns an interface for reading the state of this aggregator.
-func (c *Aggregator) Aggregation() aggregation.Aggregation {
-	return c
-}
-
-// Kind returns aggregation.ExactKind.
-func (c *Aggregator) Kind() aggregation.Kind {
-	return aggregation.ExactKind
-}
-
-// Sum returns the sum of values in the checkpoint.
-func (c *Aggregator) Sum() (number.Number, error) {
-	return c.sum, nil
-}
-
-// Count returns the number of values in the checkpoint.
-func (c *Aggregator) Count() (uint64, error) {
-	return uint64(len(c.points)), nil
-}
-
-// Max returns the maximum value in the checkpoint.
-func (c *Aggregator) Max() (number.Number, error) {
-	return c.points.Quantile(1)
-}
-
-// Min returns the mininum value in the checkpoint.
-func (c *Aggregator) Min() (number.Number, error) {
-	return c.points.Quantile(0)
-}
-
-// Quantile returns the estimated quantile of data in the checkpoint.
-// It is an error if `q` is less than 0 or greated than 1.
-func (c *Aggregator) Quantile(q float64) (number.Number, error) {
-	return c.points.Quantile(q)
-}
-
-// Points returns access to the raw data set.
-func (c *Aggregator) Points() ([]number.Number, error) {
-	return c.points, nil
-}
-
-// SynchronizedMove saves the current state to oa and resets the current state to
-// the empty set, taking a lock to prevent concurrent Update() calls.
-func (c *Aggregator) SynchronizedMove(oa export.Aggregator, desc *metric.Descriptor) error {
-	o, _ := oa.(*Aggregator)
-
-	if oa != nil && o == nil {
-		return aggregator.NewInconsistentAggregatorError(c, oa)
-	}
-
-	c.lock.Lock()
-	if o != nil {
-		o.points = c.points
-		o.sum = c.sum
-	}
-	c.points = nil
-	c.sum = 0
-	c.lock.Unlock()
-
-	// TODO: This sort should be done lazily, only when quantiles
-	// are requested.  The SDK specification says you can use this
-	// aggregator to simply list values in the order they were
-	// received as an alternative to requesting quantile information.
-	if o != nil {
-		o.sort(desc.NumberKind())
-	}
-	return nil
-}
-
-// Update adds the recorded measurement to the current data set.
-// Update takes a lock to prevent concurrent Update() and SynchronizedMove()
-// calls.
-func (c *Aggregator) Update(_ context.Context, number number.Number, desc *metric.Descriptor) error {
-	c.lock.Lock()
-	c.points = append(c.points, number)
-	c.sum.AddNumber(desc.NumberKind(), number)
-	c.lock.Unlock()
-
-	return nil
-}
-
-// Merge combines two data sets into one.
-func (c *Aggregator) Merge(oa export.Aggregator, desc *metric.Descriptor) error {
-	o, _ := oa.(*Aggregator)
-	if o == nil {
-		return aggregator.NewInconsistentAggregatorError(c, oa)
-	}
-
-	// Note: Current assumption is that `o` was checkpointed,
-	// therefore is already sorted.  See the TODO above, since
-	// this is an open question.
-	c.sum.AddNumber(desc.NumberKind(), o.sum)
-	c.points = combine(c.points, o.points, desc.NumberKind())
-	return nil
-}
-
-func (c *Aggregator) sort(kind number.Kind) {
-	switch kind {
-	case number.Float64Kind:
-		sort.Float64s(*(*[]float64)(unsafe.Pointer(&c.points)))
-
-	case number.Int64Kind:
-		sort.Sort(&c.points)
-
-	default:
-		// NOTE: This can't happen because the SDK doesn't
-		// support uint64-kind metric instruments.
-		panic("Impossible case")
-	}
-}
-
-func combine(a, b points, kind number.Kind) points {
-	result := make(points, 0, len(a)+len(b))
-
-	for len(a) != 0 && len(b) != 0 {
-		if a[0].CompareNumber(kind, b[0]) < 0 {
-			result = append(result, a[0])
-			a = a[1:]
-		} else {
-			result = append(result, b[0])
-			b = b[1:]
-		}
-	}
-	result = append(result, a...)
-	result = append(result, b...)
-	return result
-}
-
-func (p *points) Len() int {
-	return len(*p)
-}
-
-func (p *points) Less(i, j int) bool {
-	// Note this is specialized for int64, because float64 is
-	// handled by `sort.Float64s` and uint64 numbers never appear
-	// in this data.
-	return int64((*p)[i]) < int64((*p)[j])
-}
-
-func (p *points) Swap(i, j int) {
-	(*p)[i], (*p)[j] = (*p)[j], (*p)[i]
-}
-
-// Quantile returns the least X such that Pr(x<X)>=q, where X is an
-// element of the data set.  This uses the "Nearest-Rank" definition
-// of a quantile.
-func (p *points) Quantile(q float64) (number.Number, error) {
-	if len(*p) == 0 {
-		return 0, aggregation.ErrNoData
-	}
-
-	if q < 0 || q > 1 {
-		return 0, aggregation.ErrInvalidQuantile
-	}
-
-	if q == 0 || len(*p) == 1 {
-		return (*p)[0], nil
-	} else if q == 1 {
-		return (*p)[len(*p)-1], nil
-	}
-
-	position := float64(len(*p)-1) * q
-	ceil := int(math.Ceil(position))
-	return (*p)[ceil], nil
-}

sdk/metric/aggregator/ddsketch/ddsketch.go

@@ -1,155 +0,0 @@
-// Copyright The OpenTelemetry Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-package ddsketch // import "go.opentelemetry.io/otel/sdk/metric/aggregator/ddsketch"
-
-import (
-	"context"
-	"math"
-	"sync"
-
-	sdk "github.com/DataDog/sketches-go/ddsketch"
-
-	"go.opentelemetry.io/otel/metric"
-	"go.opentelemetry.io/otel/metric/number"
-	export "go.opentelemetry.io/otel/sdk/export/metric"
-	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
-	"go.opentelemetry.io/otel/sdk/metric/aggregator"
-)
-
-// Config is an alias for the underlying DDSketch config object.
-type Config = sdk.Config
-
-// Aggregator aggregates events into a distribution.
-type Aggregator struct {
-	lock   sync.Mutex
-	cfg    *Config
-	kind   number.Kind
-	sketch *sdk.DDSketch
-}
-
-var _ export.Aggregator = &Aggregator{}
-var _ aggregation.MinMaxSumCount = &Aggregator{}
-var _ aggregation.Distribution = &Aggregator{}
-
-// New returns a new DDSketch aggregator.
-func New(cnt int, desc *metric.Descriptor, cfg *Config) []Aggregator {
-	if cfg == nil {
-		cfg = NewDefaultConfig()
-	}
-	aggs := make([]Aggregator, cnt)
-	for i := range aggs {
-		aggs[i] = Aggregator{
-			cfg:    cfg,
-			kind:   desc.NumberKind(),
-			sketch: sdk.NewDDSketch(cfg),
-		}
-	}
-	return aggs
-}
-
-// Aggregation returns an interface for reading the state of this aggregator.
-func (c *Aggregator) Aggregation() aggregation.Aggregation {
-	return c
-}
-
-// Kind returns aggregation.SketchKind.
-func (c *Aggregator) Kind() aggregation.Kind {
-	return aggregation.SketchKind
-}
-
-// NewDefaultConfig returns a new, default DDSketch config.
-func NewDefaultConfig() *Config {
-	return sdk.NewDefaultConfig()
-}
-
-// Sum returns the sum of values in the checkpoint.
-func (c *Aggregator) Sum() (number.Number, error) {
-	return c.toNumber(c.sketch.Sum()), nil
-}
-
-// Count returns the number of values in the checkpoint.
-func (c *Aggregator) Count() (uint64, error) {
-	return uint64(c.sketch.Count()), nil
-}
-
-// Max returns the maximum value in the checkpoint.
-func (c *Aggregator) Max() (number.Number, error) {
-	return c.Quantile(1)
-}
-
-// Min returns the minimum value in the checkpoint.
-func (c *Aggregator) Min() (number.Number, error) {
-	return c.Quantile(0)
-}
-
-// Quantile returns the estimated quantile of data in the checkpoint.
-// It is an error if `q` is less than 0 or greated than 1.
-func (c *Aggregator) Quantile(q float64) (number.Number, error) {
-	if c.sketch.Count() == 0 {
-		return 0, aggregation.ErrNoData
-	}
-	f := c.sketch.Quantile(q)
-	if math.IsNaN(f) {
-		return 0, aggregation.ErrInvalidQuantile
-	}
-	return c.toNumber(f), nil
-}
-
-func (c *Aggregator) toNumber(f float64) number.Number {
-	if c.kind == number.Float64Kind {
-		return number.NewFloat64Number(f)
-	}
-	return number.NewInt64Number(int64(f))
-}
-
-// SynchronizedMove saves the current state into oa and resets the current state to
-// a new sketch, taking a lock to prevent concurrent Update() calls.
-func (c *Aggregator) SynchronizedMove(oa export.Aggregator, _ *metric.Descriptor) error {
-	o, _ := oa.(*Aggregator)
-
-	if oa != nil && o == nil {
-		return aggregator.NewInconsistentAggregatorError(c, oa)
-	}
-
-	replace := sdk.NewDDSketch(c.cfg)
-	c.lock.Lock()
-	if o != nil {
-		o.sketch = c.sketch
-	}
-	c.sketch = replace
-	c.lock.Unlock()
-
-	return nil
-}
-
-// Update adds the recorded measurement to the current data set.
-// Update takes a lock to prevent concurrent Update() and SynchronizedMove()
-// calls.
-func (c *Aggregator) Update(_ context.Context, number number.Number, desc *metric.Descriptor) error {
-	c.lock.Lock()
-	defer c.lock.Unlock()
-	c.sketch.Add(number.CoerceToFloat64(desc.NumberKind()))
-	return nil
-}
-
-// Merge combines two sketches into one.
-func (c *Aggregator) Merge(oa export.Aggregator, d *metric.Descriptor) error {
-	o, _ := oa.(*Aggregator)
-	if o == nil {
-		return aggregator.NewInconsistentAggregatorError(c, oa)
-	}
-
-	c.sketch.Merge(o.sketch)
-	return nil
-}

sdk/metric/aggregator/ddsketch/ddsketch_test.go

@@ -1,221 +0,0 @@
-// Copyright The OpenTelemetry Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package ddsketch
-
-import (
-	"errors"
-	"fmt"
-	"testing"
-
-	"github.com/stretchr/testify/require"
-
-	"go.opentelemetry.io/otel/metric"
-	export "go.opentelemetry.io/otel/sdk/export/metric"
-	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
-	"go.opentelemetry.io/otel/sdk/metric/aggregator/aggregatortest"
-)
-
-const count = 1000
-
-type updateTest struct {
-}
-
-func new2(desc *metric.Descriptor) (_, _ *Aggregator) {
-	alloc := New(2, desc, NewDefaultConfig())
-	return &alloc[0], &alloc[1]
-}
-
-func new4(desc *metric.Descriptor) (_, _, _, _ *Aggregator) {
-	alloc := New(4, desc, NewDefaultConfig())
-	return &alloc[0], &alloc[1], &alloc[2], &alloc[3]
-}
-
-func checkZero(t *testing.T, agg *Aggregator, desc *metric.Descriptor) {
-	kind := desc.NumberKind()
-
-	sum, err := agg.Sum()
-	require.NoError(t, err)
-	require.Equal(t, kind.Zero(), sum)
-
-	count, err := agg.Count()
-	require.NoError(t, err)
-	require.Equal(t, uint64(0), count)
-
-	max, err := agg.Max()
-	require.True(t, errors.Is(err, aggregation.ErrNoData))
-	require.Equal(t, kind.Zero(), max)
-
-	median, err := agg.Quantile(0.5)
-	require.True(t, errors.Is(err, aggregation.ErrNoData))
-	require.Equal(t, kind.Zero(), median)
-
-	min, err := agg.Min()
-	require.True(t, errors.Is(err, aggregation.ErrNoData))
-	require.Equal(t, kind.Zero(), min)
-}
-
-func (ut *updateTest) run(t *testing.T, profile aggregatortest.Profile) {
-	descriptor := aggregatortest.NewAggregatorTest(metric.ValueRecorderInstrumentKind, profile.NumberKind)
-	agg, ckpt := new2(descriptor)
-
-	all := aggregatortest.NewNumbers(profile.NumberKind)
-	for i := 0; i < count; i++ {
-		x := profile.Random(+1)
-		all.Append(x)
-		aggregatortest.CheckedUpdate(t, agg, x, descriptor)
-
-		y := profile.Random(-1)
-		all.Append(y)
-		aggregatortest.CheckedUpdate(t, agg, y, descriptor)
-	}
-
-	err := agg.SynchronizedMove(ckpt, descriptor)
-	require.NoError(t, err)
-
-	checkZero(t, agg, descriptor)
-
-	all.Sort()
-
-	sum, err := ckpt.Sum()
-	require.Nil(t, err)
-	allSum := all.Sum()
-	require.InDelta(t,
-		(&allSum).CoerceToFloat64(profile.NumberKind),
-		sum.CoerceToFloat64(profile.NumberKind),
-		1,
-		"Same sum")
-
-	count, err := ckpt.Count()
-	require.Equal(t, all.Count(), count, "Same count")
-	require.Nil(t, err)
-
-	max, err := ckpt.Max()
-	require.Nil(t, err)
-	require.Equal(t,
-		all.Max(),
-		max,
-		"Same max")
-
-	median, err := ckpt.Quantile(0.5)
-	require.Nil(t, err)
-	allMedian := all.Median()
-	require.InDelta(t,
-		(&allMedian).CoerceToFloat64(profile.NumberKind),
-		median.CoerceToFloat64(profile.NumberKind),
-		10,
-		"Same median")
-}
-
-func TestDDSketchUpdate(t *testing.T) {
-	ut := updateTest{}
-	aggregatortest.RunProfiles(t, ut.run)
-}
-
-type mergeTest struct {
-	absolute bool
-}
-
-func (mt *mergeTest) run(t *testing.T, profile aggregatortest.Profile) {
-	descriptor := aggregatortest.NewAggregatorTest(metric.ValueRecorderInstrumentKind, profile.NumberKind)
-
-	agg1, agg2, ckpt1, ckpt2 := new4(descriptor)
-
-	all := aggregatortest.NewNumbers(profile.NumberKind)
-	for i := 0; i < count; i++ {
-		x := profile.Random(+1)
-		all.Append(x)
-		aggregatortest.CheckedUpdate(t, agg1, x, descriptor)
-
-		if !mt.absolute {
-			y := profile.Random(-1)
-			all.Append(y)
-			aggregatortest.CheckedUpdate(t, agg1, y, descriptor)
-		}
-	}
-
-	for i := 0; i < count; i++ {
-		x := profile.Random(+1)
-		all.Append(x)
-		aggregatortest.CheckedUpdate(t, agg2, x, descriptor)
-
-		if !mt.absolute {
-			y := profile.Random(-1)
-			all.Append(y)
-			aggregatortest.CheckedUpdate(t, agg2, y, descriptor)
-		}
-	}
-
-	require.NoError(t, agg1.SynchronizedMove(ckpt1, descriptor))
-	require.NoError(t, agg2.SynchronizedMove(ckpt2, descriptor))
-
-	checkZero(t, agg1, descriptor)
-	checkZero(t, agg1, descriptor)
-
-	aggregatortest.CheckedMerge(t, ckpt1, ckpt2, descriptor)
-
-	all.Sort()
-
-	aggSum, err := ckpt1.Sum()
-	require.Nil(t, err)
-	allSum := all.Sum()
-	require.InDelta(t,
-		(&allSum).CoerceToFloat64(profile.NumberKind),
-		aggSum.CoerceToFloat64(profile.NumberKind),
-		1,
-		"Same sum")
-
-	count, err := ckpt1.Count()
-	require.Equal(t, all.Count(), count, "Same count")
-	require.Nil(t, err)
-
-	max, err := ckpt1.Max()
-	require.Nil(t, err)
-	require.Equal(t,
-		all.Max(),
-		max,
-		"Same max")
-
-	median, err := ckpt1.Quantile(0.5)
-	require.Nil(t, err)
-	allMedian := all.Median()
-	require.InDelta(t,
-		(&allMedian).CoerceToFloat64(profile.NumberKind),
-		median.CoerceToFloat64(profile.NumberKind),
-		10,
-		"Same median")
-}
-
-func TestDDSketchMerge(t *testing.T) {
-	// Test absolute and non-absolute
-	for _, absolute := range []bool{false, true} {
-		t.Run(fmt.Sprint("Absolute=", absolute), func(t *testing.T) {
-			mt := mergeTest{
-				absolute: absolute,
-			}
-			// Test integer and floating point
-			aggregatortest.RunProfiles(t, mt.run)
-		})
-	}
-}
-
-func TestSynchronizedMoveReset(t *testing.T) {
-	aggregatortest.SynchronizedMoveResetTest(
-		t,
-		metric.ValueRecorderInstrumentKind,
-		func(desc *metric.Descriptor) export.Aggregator {
-			return &New(1, desc, NewDefaultConfig())[0]
-		},
-	)
-}

sdk/metric/aggregator/exact/exact.go

@@ -0,0 +1,130 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package exact // import "go.opentelemetry.io/otel/sdk/metric/aggregator/exact"
+
+import (
+	"context"
+	"sync"
+	"time"
+
+	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/number"
+	export "go.opentelemetry.io/otel/sdk/export/metric"
+	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
+	"go.opentelemetry.io/otel/sdk/metric/aggregator"
+)
+
+type (
+	// Aggregator aggregates events that form a distribution, keeping
+	// an array with the exact set of values.
+	Aggregator struct {
+		lock    sync.Mutex
+		samples []aggregation.Point
+	}
+)
+
+var _ export.Aggregator = &Aggregator{}
+var _ aggregation.Points = &Aggregator{}
+var _ aggregation.Count = &Aggregator{}
+
+// New returns cnt many new exact aggregators, which aggregate recorded
+// measurements by storing them in an array.  This type uses a mutex
+// for Update() and SynchronizedMove() concurrency.
+func New(cnt int) []Aggregator {
+	return make([]Aggregator, cnt)
+}
+
+// Aggregation returns an interface for reading the state of this aggregator.
+func (c *Aggregator) Aggregation() aggregation.Aggregation {
+	return c
+}
+
+// Kind returns aggregation.ExactKind.
+func (c *Aggregator) Kind() aggregation.Kind {
+	return aggregation.ExactKind
+}
+
+// Count returns the number of values in the checkpoint.
+func (c *Aggregator) Count() (uint64, error) {
+	return uint64(len(c.samples)), nil
+}
+
+// Points returns access to the raw data set.
+func (c *Aggregator) Points() ([]aggregation.Point, error) {
+	return c.samples, nil
+}
+
+// SynchronizedMove saves the current state to oa and resets the current state to
+// the empty set, taking a lock to prevent concurrent Update() calls.
+func (c *Aggregator) SynchronizedMove(oa export.Aggregator, desc *metric.Descriptor) error {
+	o, _ := oa.(*Aggregator)
+
+	if oa != nil && o == nil {
+		return aggregator.NewInconsistentAggregatorError(c, oa)
+	}
+
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	if o != nil {
+		o.samples = c.samples
+	}
+	c.samples = nil
+
+	return nil
+}
+
+// Update adds the recorded measurement to the current data set.
+// Update takes a lock to prevent concurrent Update() and SynchronizedMove()
+// calls.
+func (c *Aggregator) Update(_ context.Context, number number.Number, desc *metric.Descriptor) error {
+	now := time.Now()
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.samples = append(c.samples, aggregation.Point{
+		Number: number,
+		Time:   now,
+	})
+
+	return nil
+}
+
+// Merge combines two data sets into one.
+func (c *Aggregator) Merge(oa export.Aggregator, desc *metric.Descriptor) error {
+	o, _ := oa.(*Aggregator)
+	if o == nil {
+		return aggregator.NewInconsistentAggregatorError(c, oa)
+	}
+
+	c.samples = combine(c.samples, o.samples)
+	return nil
+}
+
+func combine(a, b []aggregation.Point) []aggregation.Point {
+	result := make([]aggregation.Point, 0, len(a)+len(b))
+
+	for len(a) != 0 && len(b) != 0 {
+		if a[0].Time.Before(b[0].Time) {
+			result = append(result, a[0])
+			a = a[1:]
+		} else {
+			result = append(result, b[0])
+			b = b[1:]
+		}
+	}
+	result = append(result, a...)
+	result = append(result, b...)
+	return result
+}

sdk/metric/aggregator/exact/exact_test.go

@@ -12,13 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package array
+package exact
 
 import (
-	"errors"
 	"fmt"
 	"math"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/require"
 
@@ -34,23 +34,13 @@ type updateTest struct {
 }
 
 func checkZero(t *testing.T, agg *Aggregator, desc *metric.Descriptor) {
-	kind := desc.NumberKind()
-
-	sum, err := agg.Sum()
-	require.NoError(t, err)
-	require.Equal(t, kind.Zero(), sum)
-
 	count, err := agg.Count()
 	require.NoError(t, err)
 	require.Equal(t, uint64(0), count)
 
-	max, err := agg.Max()
+	pts, err := agg.Points()
-	require.True(t, errors.Is(err, aggregation.ErrNoData))
+	require.NoError(t, err)
-	require.Equal(t, kind.Zero(), max)
+	require.Equal(t, 0, len(pts))
-
-	min, err := agg.Min()
-	require.True(t, errors.Is(err, aggregation.ErrNoData))
-	require.Equal(t, kind.Zero(), min)
 }
 
 func new2() (_, _ *Aggregator) {
@@ -63,6 +53,14 @@ func new4() (_, _, _, _ *Aggregator) {
 	return &alloc[0], &alloc[1], &alloc[2], &alloc[3]
 }
 
+func sumOf(samples []aggregation.Point, k number.Kind) number.Number {
+	var n number.Number
+	for _, s := range samples {
+		n.AddNumber(k, s.Number)
+	}
+	return n
+}
+
 func (ut *updateTest) run(t *testing.T, profile aggregatortest.Profile) {
 	descriptor := aggregatortest.NewAggregatorTest(metric.ValueRecorderInstrumentKind, profile.NumberKind)
 	agg, ckpt := new2()
@@ -86,32 +84,21 @@ func (ut *updateTest) run(t *testing.T, profile aggregatortest.Profile) {
 
 	all.Sort()
 
-	sum, err := ckpt.Sum()
+	pts, err := ckpt.Points()
 	require.Nil(t, err)
+	sum := sumOf(pts, profile.NumberKind)
 	allSum := all.Sum()
 	require.InEpsilon(t,
-		(&allSum).CoerceToFloat64(profile.NumberKind),
+		allSum.CoerceToFloat64(profile.NumberKind),
 		sum.CoerceToFloat64(profile.NumberKind),
 		0.0000001,
 		"Same sum")
 	count, err := ckpt.Count()
 	require.Nil(t, err)
 	require.Equal(t, all.Count(), count, "Same count")
-
-	min, err := ckpt.Min()
-	require.Nil(t, err)
-	require.Equal(t, all.Min(), min, "Same min")
-
-	max, err := ckpt.Max()
-	require.Nil(t, err)
-	require.Equal(t, all.Max(), max, "Same max")
-
-	qx, err := ckpt.Quantile(0.5)
-	require.Nil(t, err)
-	require.Equal(t, all.Median(), qx, "Same median")
 }
 
-func TestArrayUpdate(t *testing.T) {
+func TestExactUpdate(t *testing.T) {
 	// Test with an odd an even number of measurements
 	for count := 999; count <= 1000; count++ {
 		t.Run(fmt.Sprint("Odd=", count%2 == 1), func(t *testing.T) {
@@ -164,34 +151,32 @@ func (mt *mergeTest) run(t *testing.T, profile aggregatortest.Profile) {
 
 	aggregatortest.CheckedMerge(t, ckpt1, ckpt2, descriptor)
 
-	all.Sort()
+	pts, err := ckpt1.Points()
-
-	sum, err := ckpt1.Sum()
 	require.Nil(t, err)
+
+	received := aggregatortest.NewNumbers(profile.NumberKind)
+	for i, s := range pts {
+		received.Append(s.Number)
+
+		if i > 0 {
+			require.True(t, pts[i-1].Time.Before(pts[i].Time))
+		}
+	}
+
 	allSum := all.Sum()
+	sum := sumOf(pts, profile.NumberKind)
 	require.InEpsilon(t,
-		(&allSum).CoerceToFloat64(profile.NumberKind),
+		allSum.CoerceToFloat64(profile.NumberKind),
 		sum.CoerceToFloat64(profile.NumberKind),
 		0.0000001,
 		"Same sum - absolute")
 	count, err := ckpt1.Count()
 	require.Nil(t, err)
 	require.Equal(t, all.Count(), count, "Same count - absolute")
-
+	require.Equal(t, all, received, "Same ordered contents")
-	min, err := ckpt1.Min()
-	require.Nil(t, err)
-	require.Equal(t, all.Min(), min, "Same min - absolute")
-
-	max, err := ckpt1.Max()
-	require.Nil(t, err)
-	require.Equal(t, all.Max(), max, "Same max - absolute")
-
-	qx, err := ckpt1.Quantile(0.5)
-	require.Nil(t, err)
-	require.Equal(t, all.Median(), qx, "Same median - absolute")
 }
 
-func TestArrayMerge(t *testing.T) {
+func TestExactMerge(t *testing.T) {
 	// Test with an odd an even number of measurements
 	for count := 999; count <= 1000; count++ {
 		t.Run(fmt.Sprint("Odd=", count%2 == 1), func(t *testing.T) {
@@ -211,22 +196,10 @@ func TestArrayMerge(t *testing.T) {
 	}
 }
 
-func TestArrayErrors(t *testing.T) {
+func TestExactErrors(t *testing.T) {
 	aggregatortest.RunProfiles(t, func(t *testing.T, profile aggregatortest.Profile) {
 		agg, ckpt := new2()
 
-		_, err := ckpt.Max()
-		require.Error(t, err)
-		require.Equal(t, err, aggregation.ErrNoData)
-
-		_, err = ckpt.Min()
-		require.Error(t, err)
-		require.Equal(t, err, aggregation.ErrNoData)
-
-		_, err = ckpt.Quantile(0.1)
-		require.Error(t, err)
-		require.Equal(t, err, aggregation.ErrNoData)
-
 		descriptor := aggregatortest.NewAggregatorTest(metric.ValueRecorderInstrumentKind, profile.NumberKind)
 
 		aggregatortest.CheckedUpdate(t, agg, number.Number(0), descriptor)
@@ -239,22 +212,10 @@ func TestArrayErrors(t *testing.T) {
 		count, err := ckpt.Count()
 		require.Equal(t, uint64(1), count, "NaN value was not counted")
 		require.Nil(t, err)
-
-		num, err := ckpt.Quantile(0)
-		require.Nil(t, err)
-		require.Equal(t, num, number.Number(0))
-
-		_, err = ckpt.Quantile(-0.0001)
-		require.Error(t, err)
-		require.True(t, errors.Is(err, aggregation.ErrInvalidQuantile))
-
-		_, err = agg.Quantile(1.0001)
-		require.Error(t, err)
-		require.True(t, errors.Is(err, aggregation.ErrNoData))
 	})
 }
 
-func TestArrayFloat64(t *testing.T) {
+func TestExactFloat64(t *testing.T) {
 	descriptor := aggregatortest.NewAggregatorTest(metric.ValueRecorderInstrumentKind, number.Float64Kind)
 
 	fpsf := func(sign int) []float64 {
@@ -288,6 +249,8 @@ func TestArrayFloat64(t *testing.T) {
 
 	agg, ckpt := new2()
 
+	startTime := time.Now()
+
 	for _, f := range fpsf(1) {
 		all.Append(number.NewFloat64Number(f))
 		aggregatortest.CheckedUpdate(t, agg, number.NewFloat64Number(f), descriptor)
@@ -298,38 +261,33 @@ func TestArrayFloat64(t *testing.T) {
 		aggregatortest.CheckedUpdate(t, agg, number.NewFloat64Number(f), descriptor)
 	}
 
+	endTime := time.Now()
+
 	require.NoError(t, agg.SynchronizedMove(ckpt, descriptor))
 
-	all.Sort()
+	pts, err := ckpt.Points()
-
-	sum, err := ckpt.Sum()
 	require.Nil(t, err)
+
 	allSum := all.Sum()
-	require.InEpsilon(t, (&allSum).AsFloat64(), sum.AsFloat64(), 0.0000001, "Same sum")
+	sum := sumOf(pts, number.Float64Kind)
+	require.InEpsilon(t, allSum.AsFloat64(), sum.AsFloat64(), 0.0000001, "Same sum")
 
 	count, err := ckpt.Count()
 	require.Equal(t, all.Count(), count, "Same count")
 	require.Nil(t, err)
 
-	min, err := ckpt.Min()
-	require.Nil(t, err)
-	require.Equal(t, all.Min(), min, "Same min")
-
-	max, err := ckpt.Max()
-	require.Nil(t, err)
-	require.Equal(t, all.Max(), max, "Same max")
-
-	qx, err := ckpt.Quantile(0.5)
-	require.Nil(t, err)
-	require.Equal(t, all.Median(), qx, "Same median")
-
 	po, err := ckpt.Points()
 	require.Nil(t, err)
 	require.Equal(t, all.Len(), len(po), "Points() must have same length of updates")
 	for i := 0; i < len(po); i++ {
-		require.Equal(t, all.Points()[i], po[i], "Wrong point at position %d", i)
+		require.Equal(t, all.Points()[i], po[i].Number, "Wrong point at position %d", i)
+		if i > 0 {
+			require.True(t, po[i-1].Time.Before(po[i].Time))
 		}
 	}
+	require.True(t, po[0].Time.After(startTime))
+	require.True(t, po[len(po)-1].Time.Before(endTime))
+}
 
 func TestSynchronizedMoveReset(t *testing.T) {
 	aggregatortest.SynchronizedMoveResetTest(
@@ -340,3 +298,60 @@ func TestSynchronizedMoveReset(t *testing.T) {
 		},
 	)
 }
+
+func TestMergeBehavior(t *testing.T) {
+	aggregatortest.RunProfiles(t, func(t *testing.T, profile aggregatortest.Profile) {
+		for _, forward := range []bool{false, true} {
+			t.Run(fmt.Sprint("Forward=", forward), func(t *testing.T) {
+				descriptor := aggregatortest.NewAggregatorTest(metric.ValueRecorderInstrumentKind, profile.NumberKind)
+				agg1, agg2, ckpt, _ := new4()
+
+				all := aggregatortest.NewNumbers(profile.NumberKind)
+
+				for i := 0; i < 100; i++ {
+					x1 := profile.Random(+1)
+					all.Append(x1)
+					aggregatortest.CheckedUpdate(t, agg1, x1, descriptor)
+				}
+
+				for i := 0; i < 100; i++ {
+					x2 := profile.Random(+1)
+					all.Append(x2)
+					aggregatortest.CheckedUpdate(t, agg2, x2, descriptor)
+				}
+
+				if forward {
+					aggregatortest.CheckedMerge(t, ckpt, agg1, descriptor)
+					aggregatortest.CheckedMerge(t, ckpt, agg2, descriptor)
+				} else {
+					aggregatortest.CheckedMerge(t, ckpt, agg2, descriptor)
+					aggregatortest.CheckedMerge(t, ckpt, agg1, descriptor)
+				}
+
+				pts, err := ckpt.Points()
+				require.NoError(t, err)
+
+				received := aggregatortest.NewNumbers(profile.NumberKind)
+				for i, s := range pts {
+					received.Append(s.Number)
+
+					if i > 0 {
+						require.True(t, pts[i-1].Time.Before(pts[i].Time))
+					}
+				}
+
+				allSum := all.Sum()
+				sum := sumOf(pts, profile.NumberKind)
+				require.InEpsilon(t,
+					allSum.CoerceToFloat64(profile.NumberKind),
+					sum.CoerceToFloat64(profile.NumberKind),
+					0.0000001,
+					"Same sum - absolute")
+				count, err := ckpt.Count()
+				require.NoError(t, err)
+				require.Equal(t, all.Count(), count, "Same count - absolute")
+				require.Equal(t, all, received, "Same ordered contents")
+			})
+		}
+	})
+}

sdk/metric/aggregator/minmaxsumcount/mmsc.go

@@ -46,8 +46,7 @@ var _ export.Aggregator = &Aggregator{}
 var _ aggregation.MinMaxSumCount = &Aggregator{}
 
 // New returns a new aggregator for computing the min, max, sum, and
-// count.  It does not compute quantile information other than Min and
+// count.
-// Max.
 //
 // This type uses a mutex for Update() and SynchronizedMove() concurrency.
 func New(cnt int, desc *metric.Descriptor) []Aggregator {

sdk/metric/benchmark_test.go

@@ -458,39 +458,21 @@ func BenchmarkFloat64MaxSumCountHandleAdd(b *testing.B) {
 	benchmarkFloat64ValueRecorderHandleAdd(b, "float64.minmaxsumcount")
 }
 
-// DDSketch
+// Exact
 
-func BenchmarkInt64DDSketchAdd(b *testing.B) {
+func BenchmarkInt64ExactAdd(b *testing.B) {
-	benchmarkInt64ValueRecorderAdd(b, "int64.sketch")
-}
-
-func BenchmarkInt64DDSketchHandleAdd(b *testing.B) {
-	benchmarkInt64ValueRecorderHandleAdd(b, "int64.sketch")
-}
-
-func BenchmarkFloat64DDSketchAdd(b *testing.B) {
-	benchmarkFloat64ValueRecorderAdd(b, "float64.sketch")
-}
-
-func BenchmarkFloat64DDSketchHandleAdd(b *testing.B) {
-	benchmarkFloat64ValueRecorderHandleAdd(b, "float64.sketch")
-}
-
-// Array
-
-func BenchmarkInt64ArrayAdd(b *testing.B) {
 	benchmarkInt64ValueRecorderAdd(b, "int64.exact")
 }
 
-func BenchmarkInt64ArrayHandleAdd(b *testing.B) {
+func BenchmarkInt64ExactHandleAdd(b *testing.B) {
 	benchmarkInt64ValueRecorderHandleAdd(b, "int64.exact")
 }
 
-func BenchmarkFloat64ArrayAdd(b *testing.B) {
+func BenchmarkFloat64ExactAdd(b *testing.B) {
 	benchmarkFloat64ValueRecorderAdd(b, "float64.exact")
 }
 
-func BenchmarkFloat64ArrayHandleAdd(b *testing.B) {
+func BenchmarkFloat64ExactHandleAdd(b *testing.B) {
 	benchmarkFloat64ValueRecorderHandleAdd(b, "float64.exact")
 }
 

sdk/metric/correct_test.go

@@ -167,7 +167,7 @@ func TestInputRangeValueRecorder(t *testing.T) {
 	processor.accumulations = nil
 	checkpointed = sdk.Collect(ctx)
 
-	count, err := processor.accumulations[0].Aggregator().(aggregation.Distribution).Count()
+	count, err := processor.accumulations[0].Aggregator().(aggregation.Count).Count()
 	require.Equal(t, uint64(2), count)
 	require.Equal(t, 1, checkpointed)
 	require.Nil(t, testHandler.Flush())

sdk/metric/processor/basic/basic_test.go

@@ -77,7 +77,6 @@ func TestProcessor(t *testing.T) {
 								{kind: aggregation.HistogramKind},
 								{kind: aggregation.LastValueKind},
 								{kind: aggregation.ExactKind},
-								{kind: aggregation.SketchKind},
 							} {
 								t.Run(ac.kind.String(), func(t *testing.T) {
 									testProcessor(

sdk/metric/processor/processortest/test.go

@@ -23,10 +23,10 @@ import (
 
 	"go.opentelemetry.io/otel/label"
 	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/number"
 	export "go.opentelemetry.io/otel/sdk/export/metric"
 	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
-	"go.opentelemetry.io/otel/sdk/metric/aggregator/array"
+	"go.opentelemetry.io/otel/sdk/metric/aggregator/exact"
-	"go.opentelemetry.io/otel/sdk/metric/aggregator/ddsketch"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/histogram"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/lastvalue"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/minmaxsumcount"
@@ -183,18 +183,13 @@ func (testAggregatorSelector) AggregatorFor(desc *metric.Descriptor, aggPtrs ...
 		for i := range aggPtrs {
 			*aggPtrs[i] = &aggs[i]
 		}
-	case strings.HasSuffix(desc.Name(), ".sketch"):
-		aggs := ddsketch.New(len(aggPtrs), desc, ddsketch.NewDefaultConfig())
-		for i := range aggPtrs {
-			*aggPtrs[i] = &aggs[i]
-		}
 	case strings.HasSuffix(desc.Name(), ".histogram"):
 		aggs := histogram.New(len(aggPtrs), desc, nil)
 		for i := range aggPtrs {
 			*aggPtrs[i] = &aggs[i]
 		}
 	case strings.HasSuffix(desc.Name(), ".exact"):
-		aggs := array.New(len(aggPtrs))
+		aggs := exact.New(len(aggPtrs))
 		for i := range aggPtrs {
 			*aggPtrs[i] = &aggs[i]
 		}
@@ -260,21 +255,28 @@ func (o *Output) AddRecord(rec export.Record) error {
 func (o *Output) Map() map[string]float64 {
 	r := make(map[string]float64)
 	err := o.ForEach(export.StatelessExportKindSelector(), func(record export.Record) error {
-		for key, value := range o.m {
+		for key, entry := range o.m {
-			encoded := value.labels.Encoded(o.labelEncoder)
+			encoded := entry.labels.Encoded(o.labelEncoder)
-			rencoded := value.resource.Encoded(o.labelEncoder)
+			rencoded := entry.resource.Encoded(o.labelEncoder)
-			number := 0.0
+			value := 0.0
-			if s, ok := value.aggregator.(aggregation.Sum); ok {
+			if s, ok := entry.aggregator.(aggregation.Sum); ok {
 				sum, _ := s.Sum()
-				number = sum.CoerceToFloat64(key.desc.NumberKind())
+				value = sum.CoerceToFloat64(key.desc.NumberKind())
-			} else if l, ok := value.aggregator.(aggregation.LastValue); ok {
+			} else if l, ok := entry.aggregator.(aggregation.LastValue); ok {
 				last, _, _ := l.LastValue()
-				number = last.CoerceToFloat64(key.desc.NumberKind())
+				value = last.CoerceToFloat64(key.desc.NumberKind())
+			} else if l, ok := entry.aggregator.(aggregation.Points); ok {
+				pts, _ := l.Points()
+				var sum number.Number
+				for _, s := range pts {
+					sum.AddNumber(key.desc.NumberKind(), s.Number)
+				}
+				value = sum.CoerceToFloat64(key.desc.NumberKind())
 			} else {
-				panic(fmt.Sprintf("Unhandled aggregator type: %T", value.aggregator))
+				panic(fmt.Sprintf("Unhandled aggregator type: %T", entry.aggregator))
 			}
 			name := fmt.Sprint(key.desc.Name(), "/", encoded, "/", rencoded)
-			r[name] = number
+			r[name] = value
 		}
 		return nil
 	})

sdk/metric/selector/simple/simple.go

@@ -17,8 +17,7 @@ package simple // import "go.opentelemetry.io/otel/sdk/metric/selector/simple"
 import (
 	"go.opentelemetry.io/otel/metric"
 	export "go.opentelemetry.io/otel/sdk/export/metric"
-	"go.opentelemetry.io/otel/sdk/metric/aggregator/array"
+	"go.opentelemetry.io/otel/sdk/metric/aggregator/exact"
-	"go.opentelemetry.io/otel/sdk/metric/aggregator/ddsketch"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/histogram"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/lastvalue"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/minmaxsumcount"
@@ -28,9 +27,6 @@ import (
 type (
 	selectorInexpensive struct{}
 	selectorExact       struct{}
-	selectorSketch      struct {
-		config *ddsketch.Config
-	}
 	selectorHistogram   struct {
 		boundaries []float64
 	}
@@ -38,44 +34,31 @@ type (
 
 var (
 	_ export.AggregatorSelector = selectorInexpensive{}
-	_ export.AggregatorSelector = selectorSketch{}
 	_ export.AggregatorSelector = selectorExact{}
 	_ export.AggregatorSelector = selectorHistogram{}
 )
 
-// NewWithInexpensiveDistribution returns a simple aggregation selector
+// NewWithInexpensiveDistribution returns a simple aggregator selector
-// that uses counter, minmaxsumcount and minmaxsumcount aggregators
+// that uses minmaxsumcount aggregators for `ValueRecorder`
-// for the three kinds of metric.  This selector is faster and uses
+// instruments.  This selector is faster and uses less memory than the
-// less memory than the others because minmaxsumcount does not
+// others in this package because minmaxsumcount aggregators maintain
-// aggregate quantile information.
+// the least information about the distribution among these choices.
 func NewWithInexpensiveDistribution() export.AggregatorSelector {
 	return selectorInexpensive{}
 }
 
-// NewWithSketchDistribution returns a simple aggregation selector that
+// NewWithExactDistribution returns a simple aggregator selector that
-// uses counter, ddsketch, and ddsketch aggregators for the three
+// uses exact aggregators for `ValueRecorder` instruments.  This
-// kinds of metric.  This selector uses more cpu and memory than the
+// selector uses more memory than the others in this package because
-// NewWithInexpensiveDistribution because it uses one DDSketch per distinct
+// exact aggregators maintain the most information about the
-// instrument and label set.
+// distribution among these choices.
-func NewWithSketchDistribution(config *ddsketch.Config) export.AggregatorSelector {
-	return selectorSketch{
-		config: config,
-	}
-}
-
-// NewWithExactDistribution returns a simple aggregation selector that uses
-// counter, array, and array aggregators for the three kinds of metric.
-// This selector uses more memory than the NewWithSketchDistribution
-// because it aggregates an array of all values, therefore is able to
-// compute exact quantiles.
 func NewWithExactDistribution() export.AggregatorSelector {
 	return selectorExact{}
 }
 
-// NewWithHistogramDistribution returns a simple aggregation selector that uses counter,
+// NewWithHistogramDistribution returns a simple aggregator selector
-// histogram, and histogram aggregators for the three kinds of metric. This
+// that uses histogram aggregators for `ValueRecorder` instruments.
-// selector uses more memory than the NewWithInexpensiveDistribution because it
+// This selector is a good default choice for most metric exporters.
-// uses a counter per bucket.
 func NewWithHistogramDistribution(boundaries []float64) export.AggregatorSelector {
 	return selectorHistogram{boundaries: boundaries}
 }
@@ -108,26 +91,12 @@ func (selectorInexpensive) AggregatorFor(descriptor *metric.Descriptor, aggPtrs
 	}
 }
 
-func (s selectorSketch) AggregatorFor(descriptor *metric.Descriptor, aggPtrs ...*export.Aggregator) {
-	switch descriptor.InstrumentKind() {
-	case metric.ValueObserverInstrumentKind:
-		lastValueAggs(aggPtrs)
-	case metric.ValueRecorderInstrumentKind:
-		aggs := ddsketch.New(len(aggPtrs), descriptor, s.config)
-		for i := range aggPtrs {
-			*aggPtrs[i] = &aggs[i]
-		}
-	default:
-		sumAggs(aggPtrs)
-	}
-}
-
 func (selectorExact) AggregatorFor(descriptor *metric.Descriptor, aggPtrs ...*export.Aggregator) {
 	switch descriptor.InstrumentKind() {
 	case metric.ValueObserverInstrumentKind:
 		lastValueAggs(aggPtrs)
 	case metric.ValueRecorderInstrumentKind:
-		aggs := array.New(len(aggPtrs))
+		aggs := exact.New(len(aggPtrs))
 		for i := range aggPtrs {
 			*aggPtrs[i] = &aggs[i]
 		}

sdk/metric/selector/simple/simple_test.go

@@ -22,8 +22,7 @@ import (
 	"go.opentelemetry.io/otel/metric"
 	"go.opentelemetry.io/otel/metric/number"
 	export "go.opentelemetry.io/otel/sdk/export/metric"
-	"go.opentelemetry.io/otel/sdk/metric/aggregator/array"
+	"go.opentelemetry.io/otel/sdk/metric/aggregator/exact"
-	"go.opentelemetry.io/otel/sdk/metric/aggregator/ddsketch"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/histogram"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/lastvalue"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/minmaxsumcount"
@@ -60,15 +59,9 @@ func TestInexpensiveDistribution(t *testing.T) {
 	testFixedSelectors(t, inex)
 }
 
-func TestSketchDistribution(t *testing.T) {
-	sk := simple.NewWithSketchDistribution(ddsketch.NewDefaultConfig())
-	require.IsType(t, (*ddsketch.Aggregator)(nil), oneAgg(sk, &testValueRecorderDesc))
-	testFixedSelectors(t, sk)
-}
-
 func TestExactDistribution(t *testing.T) {
 	ex := simple.NewWithExactDistribution()
-	require.IsType(t, (*array.Aggregator)(nil), oneAgg(ex, &testValueRecorderDesc))
+	require.IsType(t, (*exact.Aggregator)(nil), oneAgg(ex, &testValueRecorderDesc))
 	testFixedSelectors(t, ex)
 }