[Metrics] Update default buckets for Explicit Bucket Histogram from spec

docs/metrics/customizing-the-sdk/README.md

@@ -235,8 +235,7 @@ with the metric are of interest to you.
 #### Specify custom boundaries for Histogram
 
 By default, the boundaries used for a Histogram are [`{ 0, 5, 10, 25, 50, 75,
-100, 250, 500,
-1000}`](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/sdk.md#explicit-bucket-histogram-aggregation).
+100, 250, 500, 750, 1000, 2500, 5000, 7500, 10000}`](https://github.com/open-telemetry/opentelemetry-specification/blob/v1.14.0/specification/metrics/sdk.md#explicit-bucket-histogram-aggregation).
 Views can be used to provide custom boundaries for a Histogram. The measurements
 are then aggregated using the custom boundaries provided instead of the the
 default boundaries. This requires the use of

src/OpenTelemetry/CHANGELOG.md

@@ -2,6 +2,11 @@
 
 ## Unreleased
 
+* Changed default bucket boundaries for Explicit Bucket Histogram from [0, 5,
+  10, 25, 50, 75, 100, 250, 500, 1000] to [0, 5, 10, 25, 50, 75, 100, 250, 500,
+  750, 1000, 2500, 5000, 7500, 10000].
+  ([#3722](https://github.com/open-telemetry/opentelemetry-dotnet/pull/3722))
+
 * Fixed an issue where `LogRecord.ForEachScope` may return scopes from a
   previous log if accessed in a custom processor before
   `BatchLogRecordExportProcessor.OnEnd` is fired.

src/OpenTelemetry/Metrics/Metric.cs

@@ -25,7 +25,7 @@ namespace OpenTelemetry.Metrics
     /// </summary>
     public sealed class Metric
     {
-        internal static readonly double[] DefaultHistogramBounds = new double[] { 0, 5, 10, 25, 50, 75, 100, 250, 500, 1000 };
+        internal static readonly double[] DefaultHistogramBounds = new double[] { 0, 5, 10, 25, 50, 75, 100, 250, 500, 750, 1000, 2500, 5000, 7500, 10000 };
 
         private readonly AggregatorStore aggStore;
 

test/OpenTelemetry.Exporter.Prometheus.HttpListener.Tests/PrometheusSerializerTests.cs

@@ -273,7 +273,12 @@ public void HistogramZeroDimension()
                     + "test_histogram_bucket{le='100'} 2 \\d+\n"
                     + "test_histogram_bucket{le='250'} 2 \\d+\n"
                     + "test_histogram_bucket{le='500'} 2 \\d+\n"
+                    + "test_histogram_bucket{le='750'} 2 \\d+\n"
                     + "test_histogram_bucket{le='1000'} 2 \\d+\n"
+                    + "test_histogram_bucket{le='2500'} 2 \\d+\n"
+                    + "test_histogram_bucket{le='5000'} 2 \\d+\n"
+                    + "test_histogram_bucket{le='7500'} 2 \\d+\n"
+                    + "test_histogram_bucket{le='10000'} 2 \\d+\n"
                     + "test_histogram_bucket{le='\\+Inf'} 2 \\d+\n"
                     + "test_histogram_sum 118 \\d+\n"
                     + "test_histogram_count 2 \\d+\n"
@@ -312,7 +317,12 @@ public void HistogramOneDimension()
                     + "test_histogram_bucket{x='1',le='100'} 2 \\d+\n"
                     + "test_histogram_bucket{x='1',le='250'} 2 \\d+\n"
                     + "test_histogram_bucket{x='1',le='500'} 2 \\d+\n"
+                    + "test_histogram_bucket{x='1',le='750'} 2 \\d+\n"
                     + "test_histogram_bucket{x='1',le='1000'} 2 \\d+\n"
+                    + "test_histogram_bucket{x='1',le='2500'} 2 \\d+\n"
+                    + "test_histogram_bucket{x='1',le='5000'} 2 \\d+\n"
+                    + "test_histogram_bucket{x='1',le='7500'} 2 \\d+\n"
+                    + "test_histogram_bucket{x='1',le='10000'} 2 \\d+\n"
                     + "test_histogram_bucket{x='1',le='\\+Inf'} 2 \\d+\n"
                     + "test_histogram_sum{x='1'} 118 \\d+\n"
                     + "test_histogram_count{x='1'} 2 \\d+\n"
@@ -351,7 +361,12 @@ public void HistogramTwoDimensions()
                     + "test_histogram_bucket{x='1',y='2',le='100'} 2 \\d+\n"
                     + "test_histogram_bucket{x='1',y='2',le='250'} 2 \\d+\n"
                     + "test_histogram_bucket{x='1',y='2',le='500'} 2 \\d+\n"
+                    + "test_histogram_bucket{x='1',y='2',le='750'} 2 \\d+\n"
                     + "test_histogram_bucket{x='1',y='2',le='1000'} 2 \\d+\n"
+                    + "test_histogram_bucket{x='1',y='2',le='2500'} 2 \\d+\n"
+                    + "test_histogram_bucket{x='1',y='2',le='5000'} 2 \\d+\n"
+                    + "test_histogram_bucket{x='1',y='2',le='7500'} 2 \\d+\n"
+                    + "test_histogram_bucket{x='1',y='2',le='10000'} 2 \\d+\n"
                     + "test_histogram_bucket{x='1',y='2',le='\\+Inf'} 2 \\d+\n"
                     + "test_histogram_sum{x='1',y='2'} 118 \\d+\n"
                     + "test_histogram_count{x='1',y='2'} 2 \\d+\n"
@@ -391,7 +406,12 @@ public void HistogramInfinities()
                     + "test_histogram_bucket{le='100'} 1 \\d+\n"
                     + "test_histogram_bucket{le='250'} 1 \\d+\n"
                     + "test_histogram_bucket{le='500'} 1 \\d+\n"
+                    + "test_histogram_bucket{le='750'} 1 \\d+\n"
                     + "test_histogram_bucket{le='1000'} 1 \\d+\n"
+                    + "test_histogram_bucket{le='2500'} 1 \\d+\n"
+                    + "test_histogram_bucket{le='5000'} 1 \\d+\n"
+                    + "test_histogram_bucket{le='7500'} 1 \\d+\n"
+                    + "test_histogram_bucket{le='10000'} 1 \\d+\n"
                     + "test_histogram_bucket{le='\\+Inf'} 3 \\d+\n"
                     + "test_histogram_sum \\+Inf \\d+\n"
                     + "test_histogram_count 3 \\d+\n"
@@ -431,7 +451,12 @@ public void HistogramNaN()
                     + "test_histogram_bucket{le='100'} 1 \\d+\n"
                     + "test_histogram_bucket{le='250'} 1 \\d+\n"
                     + "test_histogram_bucket{le='500'} 1 \\d+\n"
+                    + "test_histogram_bucket{le='750'} 1 \\d+\n"
                     + "test_histogram_bucket{le='1000'} 1 \\d+\n"
+                    + "test_histogram_bucket{le='2500'} 1 \\d+\n"
+                    + "test_histogram_bucket{le='5000'} 1 \\d+\n"
+                    + "test_histogram_bucket{le='7500'} 1 \\d+\n"
+                    + "test_histogram_bucket{le='10000'} 1 \\d+\n"
                     + "test_histogram_bucket{le='\\+Inf'} 3 \\d+\n"
                     + "test_histogram_sum Nan \\d+\n"
                     + "test_histogram_count 3 \\d+\n"

test/OpenTelemetry.Tests/Metrics/AggregatorTest.cs

@@ -45,15 +45,25 @@ public void HistogramDistributeToAllBucketsDefault()
             histogramPoint.Update(250);
             histogramPoint.Update(499);
             histogramPoint.Update(500);
-            histogramPoint.Update(999);
+            histogramPoint.Update(501);
+            histogramPoint.Update(750);
+            histogramPoint.Update(751);
             histogramPoint.Update(1000);
             histogramPoint.Update(1001);
+            histogramPoint.Update(2500);
+            histogramPoint.Update(2501);
+            histogramPoint.Update(5000);
+            histogramPoint.Update(5001);
+            histogramPoint.Update(7500);
+            histogramPoint.Update(7501);
+            histogramPoint.Update(10000);
+            histogramPoint.Update(10001);
             histogramPoint.Update(10000000);
             histogramPoint.TakeSnapshot(true);
 
             var count = histogramPoint.GetHistogramCount();
 
-            Assert.Equal(22, count);
+            Assert.Equal(32, count);
 
             int actualCount = 0;
             foreach (var histogramMeasurement in histogramPoint.GetHistogramBuckets())

test/OpenTelemetry.Tests/Metrics/MetricAPITest.cs

@@ -1404,29 +1404,29 @@ public void MultithreadedDoubleCounterTest()
         [Fact]
         public void MultithreadedLongHistogramTest()
         {
-            var expected = new long[11];
+            var expected = new long[16];
             for (var i = 0; i < expected.Length; i++)
             {
                 expected[i] = NumberOfThreads * NumberOfMetricUpdateByEachThread;
             }
 
-            // Metric.DefaultHistogramBounds: 0, 5, 10, 25, 50, 75, 100, 250, 500, 1000
-            var values = new long[] { -1, 1, 6, 20, 40, 60, 80, 200, 300, 600, 1001 };
+            // Metric.DefaultHistogramBounds: 0, 5, 10, 25, 50, 75, 100, 250, 500, 750, 1000, 2500, 5000, 7500, 10000
+            var values = new long[] { -1, 1, 6, 20, 40, 60, 80, 200, 300, 600, 800, 1001, 3000, 6000, 8000, 10001 };
 
             this.MultithreadedHistogramTest(expected, values);
         }
 
         [Fact]
         public void MultithreadedDoubleHistogramTest()
         {
-            var expected = new long[11];
+            var expected = new long[16];
             for (var i = 0; i < expected.Length; i++)
             {
                 expected[i] = NumberOfThreads * NumberOfMetricUpdateByEachThread;
             }
 
-            // Metric.DefaultHistogramBounds: 0, 5, 10, 25, 50, 75, 100, 250, 500, 1000
-            var values = new double[] { -1.0, 1.0, 6.0, 20.0, 40.0, 60.0, 80.0, 200.0, 300.0, 600.0, 1001.0 };
+            // Metric.DefaultHistogramBounds: 0, 5, 10, 25, 50, 75, 100, 250, 500, 750, 1000, 2500, 5000, 7500, 10000
+            var values = new double[] { -1.0, 1.0, 6.0, 20.0, 40.0, 60.0, 80.0, 200.0, 300.0, 600.0, 800.0, 1001.0, 3000.0, 6000.0, 8000.0, 10001.0 };
 
             this.MultithreadedHistogramTest(expected, values);
         }

test/OpenTelemetry.Tests/Metrics/MetricViewTests.cs

@@ -534,7 +534,7 @@ public void ViewToProduceCustomHistogramBound()
 
             int index = 0;
             int actualCount = 0;
-            var expectedBucketCounts = new long[] { 2, 1, 2, 2, 0, 0, 0, 0, 0, 0, 0 };
+            var expectedBucketCounts = new long[] { 2, 1, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
             foreach (var histogramMeasurement in histogramPoint.GetHistogramBuckets())
             {
                 Assert.Equal(expectedBucketCounts[index], histogramMeasurement.BucketCount);