HttpTimeoutPolicy Improvements Phase 3: Fixes the TimeoutPolicies to Have Segregated Timeouts for Point-Reads and Non-Point-Reads with Uniform Timeouts

Microsoft.Azure.Cosmos/src/HttpClient/HttpTimeoutPolicyForPartitionFailover.cs

@@ -24,7 +24,7 @@ private HttpTimeoutPolicyForPartitionFailover(bool isPointRead)
         // For non-point reads: 3 attempts with timeouts of 6s, 6s, and 10s respectively.
         private readonly IReadOnlyList<(TimeSpan requestTimeout, TimeSpan delayForNextRequest)> TimeoutsAndDelaysForPointReads = new List<(TimeSpan requestTimeout, TimeSpan delayForNextRequest)>()
         {
-            (TimeSpan.FromSeconds(1), TimeSpan.Zero),
+            (TimeSpan.FromSeconds(ConfigurationManager.GetHttpFirstRetryTimeoutForPPAFPointReadsInSeconds()), TimeSpan.Zero),
             (TimeSpan.FromSeconds(6), TimeSpan.Zero),
             (TimeSpan.FromSeconds(6), TimeSpan.Zero),
         };

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

@@ -123,7 +123,12 @@ internal static class ConfigurationManager
         /// By default length aware range comparator is enabled. Refer to Range.cs in Msdata project for more details. Range.LengthAwareMinComparer/LengthAwareMaxComparer.
         /// Setting the value to false will disable length aware range comparator and switch to using the regular Range.MinComparer/MaxComparer.
         /// </summary>
-        internal static readonly string UseLengthAwareRangeComparator = "AZURE_COSMOS_USE_LENGTH_AWARE_RANGE_COMPARATOR";
+        internal static readonly string UseLengthAwareRangeComparator = "AZURE_COSMOS_USE_LENGTH_AWARE_RANGE_COMPARATOR";
+
+        /// <summary>
+        /// A read-only string containing the environment variable name for capturing the http first retry timeout in seconds applicable for PPAF point reads
+        /// </summary>
+        internal static readonly string HttpFirstRetryTimeoutForPPAFPointReads = "AZURE_COSMOS_PPAF_POINT_READS_HTTP_FIRST_RETY_TIMEOUT_IN_SECONDS";
 
         public static T GetEnvironmentVariable<T>(string variable, T defaultValue)
         {
@@ -400,6 +405,21 @@ public static bool IsLengthAwareRangeComparatorEnabled()
                     .GetEnvironmentVariable(
                         variable: ConfigurationManager.UseLengthAwareRangeComparator,
                         defaultValue: defaultValue);
+        }
+
+        /// <summary>
+        /// Gets http retry timeout value for first retry in case of PPAF point reads.
+        /// The default value is 1 second. The user can set the respective
+        /// environment variable 'AZURE_COSMOS_PPAF_POINT_READS_HTTP_FIRST_RETY_TIMEOUT_IN_SECONDS'
+        /// to override the value.
+        /// </summary>
+        /// <returns>An integer representing the refresh interval in seconds.</returns>
+        public static int GetHttpFirstRetryTimeoutForPPAFPointReadsInSeconds()
+        {
+            return ConfigurationManager
+                    .GetEnvironmentVariable(
+                        variable: ConfigurationManager.HttpFirstRetryTimeoutForPPAFPointReads,
+                        defaultValue: 1);
         }
     }
 }

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

@@ -640,6 +640,38 @@ public void HttpTimeoutPolicyForParitionFailoverForReads()
             }
         }
 
+        [TestMethod]
+        public void HttpTimeoutPolicyForParitionFailoverConfigurableTimeoutForReads()
+        {
+            Environment.SetEnvironmentVariable(ConfigurationManager.HttpFirstRetryTimeoutForPPAFPointReads, "4");
+            try
+            {
+                HttpTimeoutPolicy httpTimeoutPolicyForQuery = HttpTimeoutPolicy.GetTimeoutPolicy(
+                        documentServiceRequest: CosmosHttpClientCoreTests.CreateDocumentServiceRequestByOperation(ResourceType.Document, OperationType.Read),
+                        isPartitionLevelFailoverEnabled: true,
+                        isThinClientEnabled: false);
+                IEnumerator<(TimeSpan requestTimeout, TimeSpan delayForNextRequest)> availableRetries = httpTimeoutPolicyForQuery.GetTimeoutEnumerator();
+
+                int count = 0;
+                while (availableRetries.MoveNext())
+                {
+                    if (count == 0)
+                    {
+                        Assert.AreEqual(new TimeSpan(0, 0, 4), availableRetries.Current.requestTimeout);
+                    }
+                    else if (count == 1 || count == 2)
+                    {
+                        Assert.AreEqual(new TimeSpan(0, 0, 6), availableRetries.Current.requestTimeout);
+                    }
+                    count++;
+                }
+            }
+            finally
+            {
+                Environment.SetEnvironmentVariable(ConfigurationManager.HttpFirstRetryTimeoutForPPAFPointReads, null);
+            }
+        }
+
         private static DocumentServiceRequest CreateDocumentServiceRequestByOperation(
             ResourceType resourceType,
             OperationType operationType)