Fixed ReadAsync blocking issue (#26595)

Author: Gene Lee

src/System.Data.SqlClient/src/System/Data/SqlClient/TdsParser.cs

@@ -2499,9 +2499,6 @@ private bool TryProcessDone(SqlCommand cmd, SqlDataReader reader, ref RunBehavio
             ushort status;
             int count;
 
-            // Can't retry TryProcessDone
-            stateObj._syncOverAsync = true;
-
             // status
             // command
             // rowcount (valid only if DONE_COUNT bit is set)

src/System.Data.SqlClient/tests/ManualTests/SQL/AsyncTest/AsyncTest.cs

@@ -2,94 +2,104 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Diagnostics;
 using System.Threading.Tasks;
 using Xunit;
 
 namespace System.Data.SqlClient.ManualTesting.Tests
 {
     public static class AsyncTest
     {
-        private const int TaskTimeout = 5000;
-
         [CheckConnStrSetupFact]
-        public static void ExecuteTest()
+        public static void TestReadAsyncTimeConsumed()
         {
-            SqlCommand com = new SqlCommand("select * from Orders");
-            SqlConnection con = new SqlConnection(DataTestUtility.TcpConnStr);
-
-            com.Connection = con;
-
-            con.Open();
-
-            Task<SqlDataReader> readerTask = com.ExecuteReaderAsync();
-            bool taskCompleted = readerTask.Wait(TaskTimeout);
-            Assert.True(taskCompleted, "FAILED: ExecuteReaderAsync Task did not complete successfully.");
-
-            SqlDataReader reader = readerTask.Result;
-
-            int rows;
-            for (rows = 0; reader.Read(); rows++) ;
-
-            Assert.True(rows == 830, string.Format("FAILED: ExecuteTest reader had wrong number of rows. Expected: {0}. Actual: {1}", 830, rows));
-
-            reader.Dispose();
-            con.Close();
+            const string sql = "SET NOCOUNT ON"
+                            + " SELECT 'a'"
+                            + " DECLARE @t DATETIME = SYSDATETIME()"
+                            + " WHILE DATEDIFF(s, @t, SYSDATETIME()) < 20 BEGIN"
+                            + "   SELECT 2 x INTO #y"
+                            + "   DROP TABLE #y"
+                            + " END"
+                            + " SELECT 'b'";
+            Task<double> t = RunReadAsync(sql);
+            double elapsedSync = RunReadSync(sql);
+            t.Wait();
+            double elapsedAsync = t.Result;
+            Assert.True(elapsedAsync < elapsedSync, "Asynchronous operation should be finished quicker than synchronous one");
+            int limit = 100;
+            Assert.True(elapsedAsync < limit, $"Asynchronous operation should be finished within {limit}ms");
         }
 
-        [CheckConnStrSetupFact]
-        public static void FailureTest()
+        private static async Task<double> RunReadAsync(string sql)
         {
-            bool failure = false;
-            bool taskCompleted = false;
-
-            SqlCommand com = new SqlCommand("select * from Orders");
-            SqlConnection con = new SqlConnection((new SqlConnectionStringBuilder(DataTestUtility.TcpConnStr) { Pooling = false }).ConnectionString);
-            com.Connection = con;
-            con.Open();
-
-            Task<int> nonQueryTask = com.ExecuteNonQueryAsync();
-            try
+            double maxElapsedTimeMillisecond = 0;
+            using (SqlConnection connection = new SqlConnection(DataTestUtility.TcpConnStr))
             {
-                com.ExecuteNonQueryAsync().Wait(TaskTimeout);
-            }
-            catch (AggregateException agrEx)
-            {
-                agrEx.Handle(
-                    (ex) =>
+                await connection.OpenAsync();
+                using (SqlCommand command = connection.CreateCommand())
+                {
+                    command.CommandText = sql;
+                    using (SqlDataReader reader = await command.ExecuteReaderAsync())
                     {
-                        Assert.True(ex is InvalidOperationException, "FAILED: Thrown exception for ExecuteNonQueryAsync was not an InvalidOperationException");
-                        failure = true;
-                        return true;
-                    });
+                        Task<bool> t;
+                        Stopwatch stopwatch = new Stopwatch();
+                        do
+                        {
+                            do
+                            {
+                                stopwatch.Start();
+                                t = reader.ReadAsync();
+                                stopwatch.Stop();
+                                double elased = stopwatch.Elapsed.TotalMilliseconds;
+                                if (maxElapsedTimeMillisecond < elased)
+                                {
+                                    maxElapsedTimeMillisecond = elased;
+                                }
+                            }
+                            while (await t);
+                        }
+                        while (reader.NextResult());
+                    }
+                }
             }
-            Assert.True(failure, "FAILED: No exception thrown after trying second ExecuteNonQueryAsync.");
-            failure = false;
 
-            taskCompleted = nonQueryTask.Wait(TaskTimeout);
-            Assert.True(taskCompleted, "FAILED: ExecuteNonQueryAsync Task did not complete successfully.");
+            return maxElapsedTimeMillisecond;
+        }
 
-            Task<SqlDataReader> readerTask = com.ExecuteReaderAsync();
-            try
-            {
-                com.ExecuteReaderAsync().Wait(TaskTimeout);
-            }
-            catch (AggregateException agrEx)
+        private static double RunReadSync(string sql)
+        {
+            double maxElapsedTimeMillisecond = 0;
+            using (SqlConnection connection = new SqlConnection(DataTestUtility.TcpConnStr))
             {
-                agrEx.Handle(
-                    (ex) =>
+                connection.Open();
+                using (SqlCommand command = connection.CreateCommand())
+                {
+                    command.CommandText = sql;
+                    using (SqlDataReader reader = command.ExecuteReader())
                     {
-                        Assert.True(ex is InvalidOperationException, "FAILED: Thrown exception for ExecuteReaderAsync was not an InvalidOperationException: " + ex);
-                        failure = true;
-                        return true;
-                    });
+                        bool result;
+                        Stopwatch stopwatch = new Stopwatch();
+                        do
+                        {
+                            do
+                            {
+                                stopwatch.Start();
+                                result = reader.Read();
+                                stopwatch.Stop();
+                                double elased = stopwatch.Elapsed.TotalMilliseconds;
+                                if (maxElapsedTimeMillisecond < elased)
+                                {
+                                    maxElapsedTimeMillisecond = elased;
+                                }
+                            }
+                            while (result);
+                        }
+                        while (reader.NextResult());
+                    }
+                }
             }
-            Assert.True(failure, "FAILED: No exception thrown after trying second ExecuteReaderAsync.");
-
-            taskCompleted = readerTask.Wait(TaskTimeout);
-            Assert.True(taskCompleted, "FAILED: ExecuteReaderAsync Task did not complete successfully.");
 
-            readerTask.Result.Dispose();
-            con.Close();
+            return maxElapsedTimeMillisecond;
         }
     }
 }