Add change rate perf test

performance/SqlBindingBenchmarks.cs

@@ -44,6 +44,10 @@ public static void Main(string[] args)
             {
                 BenchmarkRunner.Run<SqlTriggerBindingPerformance_Parallelization>();
             }
+            if (runAll || args.Contains("trigger_changerate"))
+            {
+                BenchmarkRunner.Run<SqlTriggerBindingPerformance_ChangeRate>();
+            }
         }
     }
 }

performance/SqlTriggerBindingPerformance_ChangeRate.cs

@@ -0,0 +1,89 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System.Threading.Tasks;
+using Microsoft.Azure.WebJobs.Extensions.Sql.Samples.TriggerBindingSamples;
+using Microsoft.Azure.WebJobs.Extensions.Sql.Tests.Common;
+using BenchmarkDotNet.Attributes;
+using System.Threading;
+using Microsoft.Azure.WebJobs.Extensions.Sql.Tests.Integration;
+using System;
+
+namespace Microsoft.Azure.WebJobs.Extensions.Sql.Performance
+{
+    [MemoryDiagnoser]
+    public class SqlTriggerBindingPerformance_ChangeRate : IDisposable
+    {
+        private SqlTriggerBindingIntegrationTests TestObject;
+
+        [IterationSetup]
+        public void IterationSetup()
+        {
+            // We start a new instance each iteration because this test constantly inserts items
+            // which results in more items being inserted than the test looks for (intentionally).
+            // If we used the same trigger function for all runs then we run into issues with leftover
+            // items from previous runs being picked up by the new function - so to get around this
+            // we have to take the overhead hit of starting the function host each iteration to ensure
+            // a completely clean start for each iteration.
+            this.TestObject = new SqlTriggerBindingIntegrationTests();
+            this.TestObject.SetChangeTrackingForTable("Products", true);
+            this.TestObject.StartFunctionHost(nameof(ProductsTrigger), SupportedLanguages.CSharp);
+        }
+
+        [IterationCleanup]
+        public void IterationCleanup()
+        {
+            this.TestObject.Dispose();
+        }
+
+        /// <summary>
+        /// Runs a test with a high constant change rate. Items are inserted constantly until the test
+        /// detects that the specified number of items has been processed. Note this will NOT be all
+        /// of the items sent - those are being inserted at a much higher rate than the function can deal
+        /// with.
+        /// </summary>
+        /// <param name="count">The number of items to process before ending the test</param>
+        [Benchmark]
+        [Arguments(1000)]
+        public async Task ChangeRate(int count)
+        {
+            var tokenSource = new CancellationTokenSource();
+            await this.TestObject.WaitForProductChanges(
+                1,
+                count,
+                SqlChangeOperation.Insert,
+                () => { this.ChangesLoop(tokenSource.Token); return Task.CompletedTask; },
+                id => $"Product {id}",
+                id => id * 100,
+                this.TestObject.GetBatchProcessingTimeout(1, count)); // Wait for up to 30 seconds
+            tokenSource.Cancel();
+        }
+
+        private void ChangesLoop(CancellationToken token)
+        {
+            // Start off worker to insert items but then immediately return since
+            // we're only going to be watching for a subset of the inserted items
+            _ = Task.Run(() =>
+            {
+                const int ChangesInBatch = 50;
+                int startIndex = 1, endIndex = ChangesInBatch;
+                while (!token.IsCancellationRequested)
+                {
+                    this.TestObject.InsertProducts(startIndex, endIndex);
+                    startIndex += ChangesInBatch;
+                    endIndex += ChangesInBatch;
+                    // No specific reason for this delay except to avoid having this take
+                    // up too many cycles when running the tests. 1 item/ms is fast enough
+                    // for our purposes currently
+                    Thread.Sleep(50);
+                }
+            }, token);
+        }
+
+        public void Dispose()
+        {
+            GC.SuppressFinalize(this);
+            this.TestObject.Dispose();
+        }
+    }
+}

test/Integration/SqlTriggerBindingIntegrationTestBase.cs

@@ -187,7 +187,7 @@ void OutputHandler(object sender, DataReceivedEventArgs e)
         /// <param name="batchSize">The batch size if different than the default batch size</param>
         /// <param name="pollingIntervalMs">The polling interval in ms if different than the default polling interval</param>
         /// <returns></returns>
-        protected int GetBatchProcessingTimeout(int firstId, int lastId, int batchSize = SqlTableChangeMonitor<object>.DefaultBatchSize, int pollingIntervalMs = SqlTableChangeMonitor<object>.DefaultPollingIntervalMs)
+        public int GetBatchProcessingTimeout(int firstId, int lastId, int batchSize = SqlTableChangeMonitor<object>.DefaultBatchSize, int pollingIntervalMs = SqlTableChangeMonitor<object>.DefaultPollingIntervalMs)
         {
             int changesToProcess = lastId - firstId + 1;
             int calculatedTimeout = (int)(Math.Ceiling((double)changesToProcess / batchSize // The number of batches to process