From 816cc5a45ee60a7891ffe489e97733219f647a7d Mon Sep 17 00:00:00 2001
From: j82w <j82w@users.noreply.github.com>
Date: Tue, 23 Feb 2021 13:56:47 -0800
Subject: [PATCH] Performance: Adds an optimization to disable Nagle Algorithm
 for HttpRequest on NetFx (#2249)

Disable Nagle for HTTP gateway mode requests;
this improves latency/throughput for Gatewaymode customers on .net Framework.
This is already the default on .net core so they should be no-op for those customers.
---
 .../src/Util/ServicePointAccessor.cs            | 17 +++++++++++++++++
 .../ServicePointAccessorTests.cs                |  9 +++++++++
 2 files changed, 26 insertions(+)

diff --git a/Microsoft.Azure.Cosmos/src/Util/ServicePointAccessor.cs b/Microsoft.Azure.Cosmos/src/Util/ServicePointAccessor.cs
index 14e415f002..6816eb015a 100644
--- a/Microsoft.Azure.Cosmos/src/Util/ServicePointAccessor.cs
+++ b/Microsoft.Azure.Cosmos/src/Util/ServicePointAccessor.cs
@@ -22,6 +22,7 @@ internal class ServicePointAccessor
         private ServicePointAccessor(ServicePoint servicePoint)
         {
             this.servicePoint = servicePoint ?? throw new ArgumentNullException(nameof(servicePoint));
+            this.TryDisableUseNagleAlgorithm();
         }
 
         internal static ServicePointAccessor FindServicePoint(Uri endpoint)
@@ -35,6 +36,22 @@ public int ConnectionLimit
             set => this.TrySetConnectionLimit(value);
         }
 
+        /// <summary>
+        /// Disable Nagle for HTTP requests.
+        /// This improves latency/throughput for Gateway operations on.net Framework
+        /// </summary>
+        private void TryDisableUseNagleAlgorithm()
+        {
+            try
+            {
+                this.servicePoint.UseNagleAlgorithm = false;
+            }
+            catch (PlatformNotSupportedException)
+            {
+                DefaultTrace.TraceWarning("ServicePoint.set_UseNagleAlgorithm - Platform does not support feature.");
+            }
+        }
+
         private void TrySetConnectionLimit(int connectionLimit)
         {
             if (ServicePointAccessor.IsBrowser)
diff --git a/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/ServicePointAccessorTests.cs b/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/ServicePointAccessorTests.cs
index f5258f2b0a..5ff15ed9a3 100644
--- a/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/ServicePointAccessorTests.cs
+++ b/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/ServicePointAccessorTests.cs
@@ -23,5 +23,14 @@ public void ServicePointAccessor_SetConnectionLimit()
             ServicePoint servicePoint = ServicePointManager.FindServicePoint(ServicePointAccessorTests.uri);
             Assert.AreEqual(limit, servicePoint.ConnectionLimit);
         }
+
+        [TestMethod]
+        public void ServicePointAccessor_DisableNagle()
+        {
+            ServicePointAccessor accessor = ServicePointAccessor.FindServicePoint(ServicePointAccessorTests.uri);
+            Assert.IsNotNull(accessor);
+            ServicePoint servicePoint = ServicePointManager.FindServicePoint(ServicePointAccessorTests.uri);
+            Assert.IsFalse(servicePoint.UseNagleAlgorithm);
+        }
     }
 }