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Sync fast path for WriteWithLength #4543

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a96470c
Sync fast path for WriteWithLength
bbowyersmyth Jul 4, 2022
458f3b4
Merge branch 'main' into bruceb/WriteWithLength
bbowyersmyth Jul 23, 2022
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79 changes: 60 additions & 19 deletions src/Npgsql/Internal/TypeHandling/NpgsqlTypeHandler.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -170,34 +170,75 @@ protected internal virtual int ValidateAndGetLengthCustom<TAny>(
/// In the vast majority of cases writing a parameter to the buffer won't need to perform I/O.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public async Task WriteWithLength<TAny>(TAny? value, NpgsqlWriteBuffer buf, NpgsqlLengthCache? lengthCache, NpgsqlParameter? parameter, bool async, CancellationToken cancellationToken = default)
public Task WriteWithLength<TAny>(TAny? value, NpgsqlWriteBuffer buf, NpgsqlLengthCache? lengthCache, NpgsqlParameter? parameter, bool async, CancellationToken cancellationToken = default)
{
// TODO: Possibly do a sync path when we don't do I/O (e.g. simple type handler, no flush)
if (buf.WriteSpaceLeft < 4)
await buf.Flush(async, cancellationToken);

if (value is null or DBNull)
{
buf.WriteInt32(-1);
return;
if (buf.WriteSpaceLeft >= sizeof(int))
{
buf.WriteInt32(-1);
return Task.CompletedTask;
}
else
{
return WriteNullAsync(buf, async, cancellationToken);
}
}

var len = 0;

switch (this)
{
case INpgsqlSimpleTypeHandler<TAny> simpleTypeHandler:
var len = simpleTypeHandler.ValidateAndGetLength(value, parameter);
buf.WriteInt32(len);
if (buf.WriteSpaceLeft < len)
await buf.Flush(async, cancellationToken);
simpleTypeHandler.Write(value, buf, parameter);
return;
len = simpleTypeHandler.ValidateAndGetLength(value, parameter);
if (buf.WriteSpaceLeft >= sizeof(int) + len)
{
buf.WriteInt32(len);
simpleTypeHandler.Write(value, buf, parameter);
return Task.CompletedTask;
}
break;
case INpgsqlTypeHandler<TAny> typeHandler:
buf.WriteInt32(typeHandler.ValidateAndGetLength(value, ref lengthCache, parameter));
await typeHandler.Write(value, buf, lengthCache, parameter, async, cancellationToken);
return;
default:
await WriteWithLengthCustom<TAny>(value, buf, lengthCache, parameter, async, cancellationToken);
return;
len = typeHandler.ValidateAndGetLength(value, ref lengthCache, parameter);
if (buf.WriteSpaceLeft >= sizeof(int))
{
buf.WriteInt32(len);
return typeHandler.Write(value, buf, lengthCache, parameter, async, cancellationToken);
}
break;
}

return WriteWithLengthAsync(value, buf, len, lengthCache, parameter, async, cancellationToken);

async static Task WriteNullAsync(NpgsqlWriteBuffer buf, bool async, CancellationToken cancellationToken)
{
if (buf.WriteSpaceLeft < 4)
await buf.Flush(async, cancellationToken);

buf.WriteInt32(-1);
}

async Task WriteWithLengthAsync([DisallowNull] TAny value, NpgsqlWriteBuffer buf, int len, NpgsqlLengthCache? lengthCache, NpgsqlParameter? parameter, bool async, CancellationToken cancellationToken)
{
if (buf.WriteSpaceLeft < 4)
await buf.Flush(async, cancellationToken);

switch (this)
{
case INpgsqlSimpleTypeHandler<TAny> simpleTypeHandler:
buf.WriteInt32(len);
if (buf.WriteSpaceLeft < len)
await buf.Flush(async, cancellationToken);
simpleTypeHandler.Write(value, buf, parameter);
break;
case INpgsqlTypeHandler<TAny> typeHandler:
buf.WriteInt32(len);
await typeHandler.Write(value, buf, lengthCache, parameter, async, cancellationToken);
break;
default:
await WriteWithLengthCustom<TAny>(value, buf, lengthCache, parameter, async, cancellationToken);
break;
}
}
}

Expand Down
10 changes: 10 additions & 0 deletions test/Npgsql.Benchmarks/TypeHandlers/Bool.cs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,10 @@
using BenchmarkDotNet.Attributes;
using Npgsql.Internal.TypeHandlers;

namespace Npgsql.Benchmarks.TypeHandlers;

[Config(typeof(Config))]
public class Bool : TypeHandlerBenchmarks<bool>
{
public Bool() : base(new BoolHandler(GetPostgresType("boolean"))) { }
}
8 changes: 4 additions & 4 deletions test/Npgsql.Benchmarks/TypeHandlers/TypeHandlerBenchmarks.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -78,12 +78,12 @@ public T Value
_value = value;
_elementSize = _handler.ValidateAndGetLength(value, ref cache, null);

cache.Rewind();
cache?.Rewind();

_handler.WriteWithLength(_value, _writeBuffer, cache, null, false);
Buffer.BlockCopy(_writeBuffer.Buffer, 0, _readBuffer.Buffer, 0, _elementSize);
Buffer.BlockCopy(_writeBuffer.Buffer, 0, _readBuffer.Buffer, 0, sizeof(int) + _elementSize);

_readBuffer.FilledBytes = _elementSize;
_readBuffer.FilledBytes = sizeof(int) + _elementSize;
_writeBuffer.WritePosition = 0;
}
}
Expand All @@ -101,4 +101,4 @@ public void Write()
_writeBuffer.WritePosition = 0;
_handler.WriteWithLength(_value, _writeBuffer, null, null, false);
}
}
}