Adds config for min and delta backoff poll intervals

CHANGELOG.md

@@ -1,10 +1,11 @@
 # Changelog
 
-## v1.1.2
+## Unreleased
 
 ### New
 
-* Support configurable backoff intervals ([#163](https://github.com/microsoft/durabletask-mssql/pull/163)) - contributed by [@tompostler](https://github.com/tompostler)
+* Support configurable max backoff intervals ([#163](https://github.com/microsoft/durabletask-mssql/pull/163)) - contributed by [@tompostler](https://github.com/tompostler)
+* Support configurable min and delta backoff intervals ([#174](https://github.com/microsoft/durabletask-mssql/pull/174)) - contributed by [@dmetzgar](https://github.com/dmetzgar)
 
 ### Updates
 

src/DurableTask.SqlServer/BackoffPollingHelper.cs

@@ -15,9 +15,9 @@ class BackoffPollingHelper
         readonly RandomizedExponentialBackoffStrategy backoffStrategy;
         readonly AsyncAutoResetEvent resetEvent;
 
-        public BackoffPollingHelper(TimeSpan minimumInterval, TimeSpan maximumInterval)
+        public BackoffPollingHelper(TimeSpan minimumInterval, TimeSpan maximumInterval, TimeSpan deltaBackoff)
         {
-            this.backoffStrategy = new RandomizedExponentialBackoffStrategy(minimumInterval, maximumInterval);
+            this.backoffStrategy = new RandomizedExponentialBackoffStrategy(minimumInterval, maximumInterval, deltaBackoff);
             this.resetEvent = new AsyncAutoResetEvent(signaled: false);
         }
 
@@ -46,11 +46,6 @@ class RandomizedExponentialBackoffStrategy
 
             uint backoffExponent;
 
-            public RandomizedExponentialBackoffStrategy(TimeSpan minimumInterval, TimeSpan maximumInterval)
-                : this(minimumInterval, maximumInterval, minimumInterval)
-            {
-            }
-
             public RandomizedExponentialBackoffStrategy(
                 TimeSpan minimumInterval,
                 TimeSpan maximumInterval,

src/DurableTask.SqlServer/SqlOrchestrationService.cs

@@ -35,8 +35,14 @@ public class SqlOrchestrationService : OrchestrationServiceBase
         public SqlOrchestrationService(SqlOrchestrationServiceSettings? settings)
         {
             this.settings = ValidateSettings(settings) ?? throw new ArgumentNullException(nameof(settings));
-            this.orchestrationBackoffHelper = new BackoffPollingHelper(TimeSpan.FromMilliseconds(50), this.settings.MaxOrchestrationPollingInterval);
-            this.activityBackoffHelper = new BackoffPollingHelper(TimeSpan.FromMilliseconds(50), this.settings.MaxActivityPollingInterval);
+            this.orchestrationBackoffHelper = new BackoffPollingHelper(
+                this.settings.MinOrchestrationPollingInterval,
+                this.settings.MaxOrchestrationPollingInterval,
+                this.settings.DeltaBackoffOrchestrationPollingInterval);
+            this.activityBackoffHelper = new BackoffPollingHelper(
+                this.settings.MinActivityPollingInterval,
+                this.settings.MaxActivityPollingInterval,
+                this.settings.DeltaBackoffActivityPollingInterval);
             this.traceHelper = new LogHelper(this.settings.LoggerFactory.CreateLogger("DurableTask.SqlServer"));
             this.dbManager = new SqlDbManager(this.settings, this.traceHelper);
             this.lockedByValue = $"{this.settings.AppName},{Process.GetCurrentProcess().Id}";

src/DurableTask.SqlServer/SqlOrchestrationServiceSettings.cs

@@ -93,6 +93,14 @@ public SqlOrchestrationServiceSettings(string connectionString, string? taskHubN
         [JsonProperty("maxActiveOrchestrations")]
         public int MaxActiveOrchestrations { get; set; } = Environment.ProcessorCount;
 
+        /// <summary>
+        /// Gets or sets the minimum interval to poll for orchestrations.
+        /// Polling interval increases when no orchestrations or activities are found.
+        /// The default value is 50 milliseconds.
+        /// </summary>
+        [JsonProperty("minOrchestrationPollingInterval")]
+        public TimeSpan MinOrchestrationPollingInterval { get; set; } = TimeSpan.FromMilliseconds(50);
+
         /// <summary>
         /// Gets or sets the maximum interval to poll for orchestrations.
         /// Polling interval increases when no orchestrations or activities are found.
@@ -101,6 +109,22 @@ public SqlOrchestrationServiceSettings(string connectionString, string? taskHubN
         [JsonProperty("maxOrchestrationPollingInterval")]
         public TimeSpan MaxOrchestrationPollingInterval { get; set; } = TimeSpan.FromSeconds(3);
 
+        /// <summary>
+        /// Gets or sets the delta backoff interval to poll for orchestrations.
+        /// Polling interval increases by this delta when no orchestrations are found.
+        /// The default value is 50 milliseconds.
+        /// </summary>
+        [JsonProperty("deltaBackoffOrchestrationPollingInterval")]
+        public TimeSpan DeltaBackoffOrchestrationPollingInterval { get; set; } = TimeSpan.FromMilliseconds(50);
+
+        /// <summary>
+        /// Gets or sets the minimum interval to poll for activities.
+        /// Polling interval increases when no activities are found.
+        /// The default value is 50 milliseconds.
+        /// </summary>
+        [JsonProperty("minActivityPollingInterval")]
+        public TimeSpan MinActivityPollingInterval { get; set; } = TimeSpan.FromMilliseconds(50);
+
         /// <summary>
         /// Gets or sets the maximum interval to poll for activities.
         /// Polling interval increases when no activities are found.
@@ -109,6 +133,14 @@ public SqlOrchestrationServiceSettings(string connectionString, string? taskHubN
         [JsonProperty("maxActivityPollingInterval")]
         public TimeSpan MaxActivityPollingInterval { get; set; } = TimeSpan.FromSeconds(3);
 
+        /// <summary>
+        /// Gets or sets the delta backoff interval to poll for activities.
+        /// Polling interval increases by this delta when no activities are found.
+        /// The default value is 50 milliseconds.
+        /// </summary>
+        [JsonProperty("deltaBackoffActivityPollingInterval")]
+        public TimeSpan DeltaBackoffActivityPollingInterval { get; set; } = TimeSpan.FromMilliseconds(50);
+
         /// <summary>
         /// Gets or sets a flag indicating whether the database should be automatically created if it does not exist.
         /// </summary>