[Internal] Open Telemetry: Fixes Metric Name and Unit changes

Author: sourabh1007

Microsoft.Azure.Cosmos/src/Telemetry/OpenTelemetry/CosmosDbClientMetrics.cs

@@ -49,7 +49,7 @@ public static class Name
                 /// <summary>
                 /// For feed operations (query, readAll, readMany, change feed) batch operations this meter capture the actual item count in responses from the service. 
                 /// </summary>
-                public const string RowCount = "db.client.response.row_count";
+                public const string RowCount = "db.client.response.returned_rows";
 
                 /// <summary>
                 /// Number of active SDK client instances. 
@@ -63,20 +63,24 @@ public static class Name
             public static class Unit
             {
                 /// <summary>
-                /// Unit representing a simple count
+                /// Unit representing active client instances
                 /// </summary>
-                public const string Count = "#";
+                public const string Instance = "{instance}";
+
+                /// <summary>
+                /// Unit representing count of items in response
+                /// </summary>
+                public const string Item = "{item}";
 
                 /// <summary>
                 /// Unit representing time in seconds
                 /// </summary>
                 public const string Sec = "s";
 
                 /// <summary>
-                /// Unit representing request units
+                /// Unit representing request units (RU)
                 /// </summary>
-                public const string RequestUnit = "# RU";
-
+                public const string RequestUnit = "{request_unit}";
             }
 
             /// <summary>

Microsoft.Azure.Cosmos/src/Telemetry/OpenTelemetry/CosmosDbOperationMeter.cs

@@ -75,11 +75,11 @@ internal static void Initialize(CosmosClientTelemetryOptions metricsOptions = nu
                 description: CosmosDbClientMetrics.OperationMetrics.Description.RequestCharge);
 
             CosmosDbOperationMeter.ActualItemHistogram ??= OperationMeter.CreateHistogram<int>(name: CosmosDbClientMetrics.OperationMetrics.Name.RowCount,
-                unit: CosmosDbClientMetrics.OperationMetrics.Unit.Count, 
+                unit: CosmosDbClientMetrics.OperationMetrics.Unit.Item,
                 description: CosmosDbClientMetrics.OperationMetrics.Description.RowCount);
 
             CosmosDbOperationMeter.ActiveInstanceCounter ??= OperationMeter.CreateUpDownCounter<int>(name: CosmosDbClientMetrics.OperationMetrics.Name.ActiveInstances,
-                unit: CosmosDbClientMetrics.OperationMetrics.Unit.Count,
+                unit: CosmosDbClientMetrics.OperationMetrics.Unit.Instance,
                 description: CosmosDbClientMetrics.OperationMetrics.Description.ActiveInstances);
 
             IsEnabled = true;

Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.EmulatorTests/Metrics/OpenTelemetryMetricsTest.cs

@@ -25,7 +25,7 @@ public class OpenTelemetryMetricsTest : BaseCosmosClientHelper
         private static readonly Dictionary<string, MetricType> expectedOperationMetrics = new()
         {
             { "db.client.operation.duration", MetricType.Histogram },
-            { "db.client.response.row_count", MetricType.Histogram},
+            { "db.client.response.returned_rows", MetricType.Histogram},
             { "azure.cosmosdb.client.operation.request_charge", MetricType.Histogram },
             { "azure.cosmosdb.client.active_instance.count", MetricType.LongSumNonMonotonic }
         };