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=