Remove result set buffering. Fixes #524

This removes result set buffering for stored procedures originally added in 8cfc592 for #135.

Also remove buffering code that is no longer necessary since the BufferResultSets option was removed in c1ec8bf.

Author: bgrainger

src/MySqlConnector/Core/ResultSet.cs

@@ -155,12 +155,6 @@ private bool IsHostVerified(MySqlConnection connection)
 				|| connection.SslMode == MySqlSslMode.VerifyFull;
 		}
 
-		public async Task BufferEntireAsync(IOBehavior ioBehavior, CancellationToken cancellationToken)
-		{
-			while (BufferState == ResultSetState.ReadingRows || BufferState == ResultSetState.ReadResultSetHeader)
-				await BufferReadAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
-		}
-
 		public async Task ReadEntireAsync(IOBehavior ioBehavior, CancellationToken cancellationToken)
 		{
 			while (State == ResultSetState.ReadingRows || State == ResultSetState.ReadResultSetHeader)

src/MySqlConnector/MySql.Data.MySqlClient/MySqlDataReader.cs

@@ -53,37 +53,18 @@ internal async Task<bool> NextResultAsync(IOBehavior ioBehavior, CancellationTok
 			try
 			{
 				await m_resultSet.ReadEntireAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
-				var nextResult = m_nextResultSetBuffer.Count > 0
-					? m_nextResultSetBuffer.Dequeue()
-					: await ScanResultSetAsync(ioBehavior, m_resultSet, cancellationToken).ConfigureAwait(false);
+				var nextResult = await ScanResultSetAsync(ioBehavior, m_resultSet, cancellationToken).ConfigureAwait(false);
 
 				if (nextResult != null)
-				{
 					ActivateResultSet(nextResult);
 
-					// https://github.com/mysql-net/MySqlConnector/issues/135
-					if (Command.CommandType == CommandType.StoredProcedure)
-					{
-						var nextRead = await nextResult.BufferReadAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
-						if (nextRead == null)
-						{
-							var nextResultSet = m_nextResultSetBuffer.Count > 0
-								? m_nextResultSetBuffer.Peek()
-								: await BufferNextResultAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
-							if (nextResultSet == null)
-								nextResult = null;
-						}
-					}
-				}
-
 				m_resultSet = nextResult ?? new ResultSet(this);
 				return nextResult != null;
 			}
 			catch (MySqlException)
 			{
 				m_resultSet = new ResultSet(this);
 				m_resultSetBuffered = null;
-				m_nextResultSetBuffer.Clear();
 				throw;
 			}
 		}
@@ -108,17 +89,6 @@ private void ActivateResultSet(ResultSet resultSet)
 			m_recordsAffected = m_recordsAffected == null ? resultSet.RecordsAffected : m_recordsAffected.Value + (resultSet.RecordsAffected ?? 0);
 		}
 
-		private async Task<ResultSet> BufferNextResultAsync(IOBehavior ioBehavior, CancellationToken cancellationToken)
-		{
-			if (m_resultSetBuffered != null)
-				await m_resultSetBuffered.BufferEntireAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
-			// ScanResultSetAsync sets m_resultSetBuffered to the next result set if there is one
-			if (await ScanResultSetAsync(ioBehavior, null, cancellationToken).ConfigureAwait(false) == null)
-				return null;
-			m_nextResultSetBuffer.Enqueue(m_resultSetBuffered);
-			return m_resultSetBuffered;
-		}
-
 		private ValueTask<ResultSet> ScanResultSetAsync(IOBehavior ioBehavior, ResultSet resultSet, CancellationToken cancellationToken)
 		{
 			if (m_resultSetBuffered == null)
@@ -448,7 +418,6 @@ private void DoClose()
 				}
 
 				m_resultSetBuffered = null;
-				m_nextResultSetBuffer.Clear();
 
 				var connection = Command.Connection;
 				connection.FinishQuerying();
@@ -483,6 +452,5 @@ private ResultSet GetResultSet()
 #if !NETSTANDARD1_3
 		DataTable m_schemaTable;
 #endif
-		readonly Queue<ResultSet> m_nextResultSetBuffer = new Queue<ResultSet>();
 	}
 }

tests/SideBySide/StoredProcedureTests.cs

@@ -363,34 +363,35 @@ public async Task MultipleRows(string paramaterName)
 			}
 		}
 
-		[Fact]
-		public async Task MultipleResultSets()
+		[Theory]
+		[InlineData(1, new string[0], new[] { "eight", "five", "four", "seven", "six", "three", "two" })]
+		[InlineData(4, new[] { "one", "three", "two" }, new[] { "eight", "five", "seven", "six" })]
+		[InlineData(8, new[] { "five", "four", "one", "seven", "six", "three", "two" }, new string[0])]
+		public async Task MultipleResultSets(int pivot, string[] firstResultSet, string[] secondResultSet)
 		{
 			using (var cmd = m_database.Connection.CreateCommand())
 			{
 				cmd.CommandText = "multiple_result_sets";
 				cmd.CommandType = CommandType.StoredProcedure;
-				cmd.Parameters.Add(new MySqlParameter { ParameterName = "@pivot", Value = 4 });
+				cmd.Parameters.Add(new MySqlParameter { ParameterName = "@pivot", Value = pivot });
 				using (var reader = await cmd.ExecuteReaderAsync())
 				{
-					Assert.True(await reader.ReadAsync());
-					Assert.Equal("one", reader.GetString(0));
-					Assert.True(await reader.ReadAsync());
-					Assert.Equal("three", reader.GetString(0));
-					Assert.True(await reader.ReadAsync());
-					Assert.Equal("two", reader.GetString(0));
+					foreach (var result in firstResultSet)
+					{
+						Assert.True(await reader.ReadAsync());
+						Assert.Equal(result, reader.GetString(0));
+					}
 					Assert.False(await reader.ReadAsync());
+
 					Assert.True(await reader.NextResultAsync());
 
-					Assert.True(await reader.ReadAsync());
-					Assert.Equal("eight", reader.GetString(0));
-					Assert.True(await reader.ReadAsync());
-					Assert.Equal("five", reader.GetString(0));
-					Assert.True(await reader.ReadAsync());
-					Assert.Equal("seven", reader.GetString(0));
-					Assert.True(await reader.ReadAsync());
-					Assert.Equal("six", reader.GetString(0));
+					foreach (var result in secondResultSet)
+					{
+						Assert.True(await reader.ReadAsync());
+						Assert.Equal(result, reader.GetString(0));
+					}
 					Assert.False(await reader.ReadAsync());
+
 					Assert.False(await reader.NextResultAsync());
 				}
 			}