Incorporate histogram min and max fields into histogram language, add…

CHANGELOG.md

@@ -14,7 +14,8 @@ release.
 ### Metrics
 
 - Add optional min / max fields to histogram data model.
-  ([#1915](https://github.com/open-telemetry/opentelemetry-specification/pull/1915))
+  ([#1915](https://github.com/open-telemetry/opentelemetry-specification/pull/1915),
+  [#1983](https://github.com/open-telemetry/opentelemetry-specification/pull/1983))
 - Add exponential histogram to the metrics data model.
   ([#1935](https://github.com/open-telemetry/opentelemetry-specification/pull/1935))
 

specification/metrics/sdk.md

@@ -301,6 +301,7 @@ The SDK MUST provide the following `Aggregation` to support the
 - [Last Value](./sdk.md#last-value-aggregation)
 - [Histogram](./sdk.md#histogram-aggregation)
 - [Explicit Bucket Histogram](./sdk.md#explicit-bucket-histogram-aggregation)
+- [Trivial Histogram](./sdk.md#trivial-histogram-aggregation)
 
 #### None Aggregation
 
@@ -384,16 +385,36 @@ This Aggregation honors the following configuration parameters:
 
 | Key | Value | Default Value | Description |
 | --- | --- | --- | --- |
-| Monotonic | boolean | true | if true, non-positive values are treated as errors<sup>1</sup>. |
 | Temporality | Delta, Cumulative | Cumulative | See [Temporality](./datamodel.md#temporality). |
 | Boundaries | double\[\] | [ 0, 5, 10, 25, 50, 75, 100, 250, 500, 1000 ] | Array of increasing values representing explicit bucket boundary values.<br><br>The Default Value represents the following buckets:<br>(-&infin;, 0], (0, 5.0], (5.0, 10.0], (10.0, 25.0], (25.0, 50.0], (50.0, 75.0], (75.0, 100.0], (100.0, 250.0], (250.0, 500.0], (500.0, 1000.0], (1000.0, +&infin;) |
 
-\[1\]: Language implementations may choose the best strategy for handling errors. (i.e. Log, Discard, etc...)
-
 This Aggregation informs the SDK to collect:
 
 - Count of `Measurement` values falling within explicit bucket boundaries.
 - Arithmetic sum of `Measurement` values in population.
+- Min `Measurement` value in population.
+- Max `Measurement` value in population.
+
+#### Trivial Histogram Aggregation
+
+The Trivial Histogram Aggregation informs the SDK to collect data for
+the [Histogram Metric Point](./datamodel.md#histogram) using a single bucket
+with boundaries (-&infin;, +&infin;). This produces lightweight histogram data
+points which capture the min, max, sum and count of a population of
+measurements.
+
+This Aggregation honors the following configuration parameters:
+
+| Key | Value | Default Value | Description |
+| --- | --- | --- | --- |
+| Temporality | Delta, Cumulative | Delta | See [Temporality](./datamodel.md#temporality). |
+
+This Aggregation informs the SDK to collect:
+
+- Count of `Measurement` values in population.
+- Arithmetic sum of `Measurement` values in population.
+- Min `Measurement` value in population.
+- Max `Measurement` value in population.
 
 ## Attribute limits
 
@@ -486,9 +507,9 @@ The SDK will come with two types of built-in exemplar reservoirs:
 1. SimpleFixedSizeExemplarReservoir
 2. AlignedHistogramBucketExemplarReservoir
 
-By default, fixed sized histogram aggregators will use
-`AlignedHistogramBucketExemplarReservoir` and all other aggregaators will use
-`SimpleFixedSizeExemplarReservoir`.
+By default, explicit bucket histogram aggregators with more than 1 bucket will
+use `AlignedHistogramBucketExemplarReservoir`. All other aggregators will
+use `SimpleFixedSizeExemplarReservoir`.
 
 *SimpleExemplarReservoir*
 This Exemplar reservoir MAY take a configuration parameter for the size of