Merge pull request #342 from bgrainger/reduce-allocations

Reduce allocations.

Author: bgrainger

src/MySqlConnector/MySqlClient/Results/ResultSet.cs

@@ -167,17 +167,17 @@ private ValueTask<Row> ScanRowAsync(IOBehavior ioBehavior, Row row, Cancellation
 		{
 			// if we've already read past the end of this resultset, Read returns false
 			if (BufferState == ResultSetState.HasMoreData || BufferState == ResultSetState.NoMoreData || BufferState == ResultSetState.None)
-				return new ValueTask<Row>((Row)null);
+				return new ValueTask<Row>((Row) null);
 
 			using (Command.RegisterCancel(cancellationToken))
 			{
 				var payloadValueTask = Session.ReceiveReplyAsync(ioBehavior, CancellationToken.None);
 				return payloadValueTask.IsCompletedSuccessfully
-					? new ValueTask<Row>(ScanRowAsyncRemainder(payloadValueTask.Result))
-					: new ValueTask<Row>(ScanRowAsyncAwaited(payloadValueTask.AsTask(), cancellationToken));
+					? new ValueTask<Row>(ScanRowAsyncRemainder(payloadValueTask.Result, row))
+					: new ValueTask<Row>(ScanRowAsyncAwaited(payloadValueTask.AsTask(), row, cancellationToken));
 			}
 
-			async Task<Row> ScanRowAsyncAwaited(Task<PayloadData> payloadTask, CancellationToken token)
+			async Task<Row> ScanRowAsyncAwaited(Task<PayloadData> payloadTask, Row row_, CancellationToken token)
 			{
 				PayloadData payloadData;
 				try
@@ -191,10 +191,10 @@ async Task<Row> ScanRowAsyncAwaited(Task<PayloadData> payloadTask, CancellationT
 						token.ThrowIfCancellationRequested();
 					throw;
 				}
-				return ScanRowAsyncRemainder(payloadData);
+				return ScanRowAsyncRemainder(payloadData, row_);
 			}
 
-			Row ScanRowAsyncRemainder(PayloadData payload)
+			Row ScanRowAsyncRemainder(PayloadData payload, Row row_)
 			{
 				if (payload.HeaderByte == EofPayload.Signature)
 				{
@@ -223,12 +223,12 @@ Row ScanRowAsyncRemainder(PayloadData payload)
 					reader.Offset += m_dataLengths[column];
 				}
 
-				if (row == null)
-					row = new Row(this);
-				row.SetData(m_dataLengths, m_dataOffsets, payload.ArraySegment);
-				m_rowBuffered = row;
+				if (row_ == null)
+					row_ = new Row(this);
+				row_.SetData(m_dataLengths, m_dataOffsets, payload.ArraySegment);
+				m_rowBuffered = row_;
 				m_hasRows = true;
-				return row;
+				return row_;
 			}
 		}
 

src/MySqlConnector/Protocol/Serialization/Packet.cs

@@ -1,16 +1,14 @@
-using System;
+using System;
 
 namespace MySql.Data.Protocol.Serialization
 {
-	internal class Packet
+	internal struct Packet
 	{
-		public Packet(int sequenceNumber, ArraySegment<byte> contents)
+		public Packet(ArraySegment<byte> contents)
 		{
-			SequenceNumber = sequenceNumber;
 			Contents = contents;
 		}
 
-		public int SequenceNumber { get; }
 		public ArraySegment<byte> Contents { get; }
 	}
 }

src/MySqlConnector/Protocol/Serialization/ProtocolUtility.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Buffers;
 using System.IO;
 using System.Threading.Tasks;
@@ -45,16 +45,16 @@ private static ValueTask<Packet> ReadPacketAfterHeader(ArraySegment<byte> header
 
 			var payloadBytesTask = bufferedByteReader.ReadBytesAsync(byteHandler, payloadLength, ioBehavior);
 			if (payloadBytesTask.IsCompleted)
-				return CreatePacketFromPayload(payloadBytesTask.Result, payloadLength, packetSequenceNumber, protocolErrorBehavior);
-			return AddContinuation(payloadBytesTask, payloadLength, packetSequenceNumber, protocolErrorBehavior);
+				return CreatePacketFromPayload(payloadBytesTask.Result, payloadLength, protocolErrorBehavior);
+			return AddContinuation(payloadBytesTask, payloadLength, protocolErrorBehavior);
 
 			// NOTE: use a local function (with no captures) to defer creation of lambda objects
-			ValueTask<Packet> AddContinuation(ValueTask<ArraySegment<byte>> payloadBytesTask_, int payloadLength_, int packetSequenceNumber_, ProtocolErrorBehavior protocolErrorBehavior_)
-				=> payloadBytesTask_.ContinueWith(x => CreatePacketFromPayload(x, payloadLength_, packetSequenceNumber_, protocolErrorBehavior_));
+			ValueTask<Packet> AddContinuation(ValueTask<ArraySegment<byte>> payloadBytesTask_, int payloadLength_, ProtocolErrorBehavior protocolErrorBehavior_)
+				=> payloadBytesTask_.ContinueWith(x => CreatePacketFromPayload(x, payloadLength_, protocolErrorBehavior_));
 		}
 
-		private static ValueTask<Packet> CreatePacketFromPayload(ArraySegment<byte> payloadBytes, int payloadLength, int packetSequenceNumber, ProtocolErrorBehavior protocolErrorBehavior) =>
-			payloadBytes.Count >= payloadLength ? new ValueTask<Packet>(new Packet(packetSequenceNumber, payloadBytes)) :
+		private static ValueTask<Packet> CreatePacketFromPayload(ArraySegment<byte> payloadBytes, int payloadLength, ProtocolErrorBehavior protocolErrorBehavior) =>
+			payloadBytes.Count >= payloadLength ? new ValueTask<Packet>(new Packet(payloadBytes)) :
 				protocolErrorBehavior == ProtocolErrorBehavior.Throw ? ValueTaskExtensions.FromException<Packet>(new EndOfStreamException()) :
 				default(ValueTask<Packet>);
 
@@ -69,8 +69,7 @@ private static ValueTask<ArraySegment<byte>> DoReadPayloadAsync(BufferedByteRead
 			var readPacketTask = ReadPacketAsync(bufferedByteReader, byteHandler, getNextSequenceNumber, protocolErrorBehavior, ioBehavior);
 			while (readPacketTask.IsCompleted)
 			{
-				ValueTask<ArraySegment<byte>> result;
-				if (HasReadPayload(previousPayloads, readPacketTask.Result, protocolErrorBehavior, out result))
+				if (HasReadPayload(previousPayloads, readPacketTask.Result, protocolErrorBehavior, out var result))
 					return result;
 
 				readPacketTask = ReadPacketAsync(bufferedByteReader, byteHandler, getNextSequenceNumber, protocolErrorBehavior, ioBehavior);
@@ -89,12 +88,6 @@ ValueTask<ArraySegment<byte>> AddContinuation(ValueTask<Packet> readPacketTask_,
 
 		private static bool HasReadPayload(ArraySegmentHolder<byte> previousPayloads, Packet packet, ProtocolErrorBehavior protocolErrorBehavior, out ValueTask<ArraySegment<byte>> result)
 		{
-			if (packet == null && protocolErrorBehavior == ProtocolErrorBehavior.Ignore)
-			{
-				result = default(ValueTask<ArraySegment<byte>>);
-				return true;
-			}
-
 			if (previousPayloads.Count == 0 && packet.Contents.Count < MaxPacketSize)
 			{
 				result = new ValueTask<ArraySegment<byte>>(packet.Contents);

tests/Benchmark/Benchmark.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFrameworks>netcoreapp1.1;net462;netcoreapp2.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp1.1;net47;netcoreapp2.0</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="BenchmarkDotNet" Version="0.10.8" />

tests/Benchmark/Program.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Data.Common;
 using System.Threading.Tasks;
 using BenchmarkDotNet.Attributes;
@@ -24,7 +24,7 @@ static void Main()
 				.With(JitOptimizationsValidator.FailOnError)
 				.With(MemoryDiagnoser.Default)
 				.With(StatisticColumn.AllStatistics)
-				.With(Job.Default.With(Runtime.Clr).With(Jit.RyuJit).With(Platform.X64).With(CsProjClassicNetToolchain.Net462).WithId("net462"))
+				.With(Job.Default.With(Runtime.Clr).With(Jit.RyuJit).With(Platform.X64).With(CsProjClassicNetToolchain.Net47).WithId("net47"))
 				.With(Job.Default.With(Runtime.Core).With(CsProjCoreToolchain.NetCoreApp11).WithId("netcore11"))
 				.With(Job.Default.With(Runtime.Core).With(CsProjCoreToolchain.NetCoreApp20).WithId("netcore20"))
 				.With(DefaultExporters.Csv);