[INTERNAL] SessionRetry: Adds support to yield immediately after the original attempt when READ_SESSION_NOT_AVAILABLE error is thrown

Microsoft.Azure.Cosmos/src/SessionRetryOptions.cs

@@ -26,12 +26,12 @@ public SessionRetryOptions()
         /// replication latency between the regions you chose
         /// </summary>
         public TimeSpan MinInRegionRetryTime { get; private set; }
-
+        
         /// <summary>
-        /// Sets the maximum number of retries within each region for read and write operations. The minimum value is 1 - the backoff time for the last in-region retry will ensure that the total retry time within the
+        /// Sets the maximum number of retries within each region for read and write operations - the backoff time for the last in-region retry will ensure that the total retry time within the
         /// region is at least the min. in-region retry time.
         /// </summary>
-        public int MaxInRegionRetryCount { get; private set; }
+        public int MaxInRegionRetryCount { get; internal set; }
 
         /// <summary>
         /// hints which guide SDK-internal retry policies on how early to switch retries to a different region. If true, will retry all replicas once and add a minimum delay before switching to the next region.If false, it will

Microsoft.Azure.Cosmos/src/Util/ConfigurationManager.cs

@@ -80,11 +80,10 @@ internal static class ConfigurationManager
         internal static readonly int MinMinInRegionRetryTimeForWritesInMs = 100;
 
         /// <summary>
-        /// intent is If a client specify a value, we will force it to be atleast 1, otherwise default is going to be 1(right now both the values are 1 but we have the provision to change them in future).
+        /// If a client specifies a value less than or equal to 0 we will not retry and yield after the original attempt, otherwise default is going to be 1
         /// </summary>
         internal static readonly string MaxRetriesInLocalRegionWhenRemoteRegionPreferred = "AZURE_COSMOS_MAX_RETRIES_IN_LOCAL_REGION_WHEN_REMOTE_REGION_PREFERRED";
         internal static readonly int DefaultMaxRetriesInLocalRegionWhenRemoteRegionPreferred = 1;
-        internal static readonly int MinMaxRetriesInLocalRegionWhenRemoteRegionPreferred = 1;
 
         /// <summary>
         /// A read-only string containing the environment variable name for enabling binary encoding. This will eventually
@@ -112,12 +111,10 @@ public static T GetEnvironmentVariable<T>(string variable, T defaultValue)
 
         public static int GetMaxRetriesInLocalRegionWhenRemoteRegionPreferred()
         {
-            return Math.Max(
-                ConfigurationManager
-                    .GetEnvironmentVariable(
-                        variable: MaxRetriesInLocalRegionWhenRemoteRegionPreferred,
-                        defaultValue: DefaultMaxRetriesInLocalRegionWhenRemoteRegionPreferred),
-                MinMaxRetriesInLocalRegionWhenRemoteRegionPreferred);
+            return ConfigurationManager
+                 .GetEnvironmentVariable(
+                     variable: MaxRetriesInLocalRegionWhenRemoteRegionPreferred,
+                     defaultValue: DefaultMaxRetriesInLocalRegionWhenRemoteRegionPreferred);
         }
 
         public static TimeSpan GetMinRetryTimeInLocalRegionWhenRemoteRegionPreferred()

Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.EmulatorTests/SessionRetryOptionsTest.cs

@@ -39,13 +39,16 @@ public async Task TestInitAsync()
         [DataRow(FaultInjectionOperationType.QueryItem, 1, true, DisplayName = "Validate Query Item operation with remote region preferred.")]
         [DataRow(FaultInjectionOperationType.ReadItem, 2, false, DisplayName = "Validate Read Item operation with local region preferred.")]
         [DataRow(FaultInjectionOperationType.QueryItem, 2, false, DisplayName = "Validate Query Item operation with local region preferred.")]
+        [DataRow(FaultInjectionOperationType.ReadItem, 0, true, DisplayName = "Validate Read Item operation with 0 sessionTokenMismatchRetryAttempts.")]
+        [DataRow(FaultInjectionOperationType.QueryItem, -1, true, DisplayName = "Validate Query Item operation with negative sessionTokenMismatchRetryAttempts.")]
         [TestCategory("MultiMaster")]
         public async Task ReadOperationWithReadSessionUnavailableTest(FaultInjectionOperationType faultInjectionOperationType,
             int sessionTokenMismatchRetryAttempts, Boolean remoteRegionPreferred)
         {
             string[] preferredRegions = this.writeRegionMap.Keys.ToArray();
             Environment.SetEnvironmentVariable(ConfigurationManager.MinInRegionRetryTimeForWritesInMs, "100");
             Environment.SetEnvironmentVariable(ConfigurationManager.MaxRetriesInLocalRegionWhenRemoteRegionPreferred, Convert.ToString(sessionTokenMismatchRetryAttempts));
+
             try
             {
                 // if I go to first region for reading an item, I should get a 404/2002 response for 10 minutes
@@ -106,7 +109,8 @@ public async Task ReadOperationWithReadSessionUnavailableTest(FaultInjectionOper
 
                     if (remoteRegionPreferred)
                     {
-                        Assert.IsTrue(hitCount >= sessionTokenMismatchRetryAttempts && hitCount <= (1 + sessionTokenMismatchRetryAttempts) * 4);
+                        int effectiveRetryAttempts = Math.Max(sessionTokenMismatchRetryAttempts, 0);
+                        Assert.IsTrue(hitCount >= effectiveRetryAttempts && hitCount <= (1 + effectiveRetryAttempts) * 4);
                     }
                 }
             }
@@ -128,6 +132,8 @@ public async Task ReadOperationWithReadSessionUnavailableTest(FaultInjectionOper
         [DataRow(FaultInjectionOperationType.DeleteItem, 2, false, DisplayName = "Validate Delete Item operation with local region preferred.")]
         [DataRow(FaultInjectionOperationType.UpsertItem, 1, false, DisplayName = "Validate Upsert Item operation with local region preferred.")]
         [DataRow(FaultInjectionOperationType.PatchItem, 1, false, DisplayName = "Validate Patch Item operation with remote region preferred.")]
+        [DataRow(FaultInjectionOperationType.CreateItem, 0, true, DisplayName = "Validate Write Item operation with 0 sessionTokenMismatchRetryAttempts.")]
+        [DataRow(FaultInjectionOperationType.ReplaceItem, -1, true, DisplayName = "Validate Replace Item operation with negative sessionTokenMismatchRetryAttempts.")]
         [TestCategory("MultiMaster")]
         public async Task WriteOperationWithReadSessionUnavailableTest(FaultInjectionOperationType faultInjectionOperationType,
            int sessionTokenMismatchRetryAttempts, Boolean remoteRegionPreferred)
@@ -193,7 +199,9 @@ public async Task WriteOperationWithReadSessionUnavailableTest(FaultInjectionOpe
                     if (remoteRegionPreferred)
                     {
                         // higher hit count is possible while in MinRetryWaitTimeWithinRegion
-                        Assert.IsTrue(hitCount >= sessionTokenMismatchRetryAttempts);
+                        int effectiveRetryAttempts = Math.Max(sessionTokenMismatchRetryAttempts, 0);
+                        // higher hit count is possible while in MinRetryWaitTimeWithinRegion
+                        Assert.IsTrue(hitCount >= effectiveRetryAttempts);
                     }
                 }
             }

Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/SessionRetryOptionsUnitTests.cs

@@ -43,7 +43,6 @@ public void SessionRetryOptionsDefaultValuesTest()
             {
                 EnableRemoteRegionPreferredForSessionRetry = true,
             };
-
             Assert.IsTrue(clientOptions.SessionRetryOptions.MinInRegionRetryTime == TimeSpan.FromMilliseconds(500));
             Assert.IsTrue(clientOptions.SessionRetryOptions.MaxInRegionRetryCount == 1);