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Avoid lambda compilation for member access expressions in LINQ #2948

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Merged
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Dec 2, 2021
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Avoid lambda compilation for member access expressions in LINQ #2948

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Avoid lambda compilation for constant and member access expressions i…
bahusoid Nov 23, 2021
00e9e20
Unwrap TargetInvocationException
bahusoid Nov 23, 2021
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15 changes: 9 additions & 6 deletions src/NHibernate/Linq/Visitors/NhPartialEvaluatingExpressionVisitor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -18,8 +18,10 @@
using System;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using NHibernate.Collection;
using NHibernate.Engine;
using NHibernate.Impl;
using NHibernate.Linq.Functions;
using NHibernate.Util;
using Remotion.Linq.Parsing;
Expand Down Expand Up @@ -143,13 +145,14 @@ private Expression EvaluateSubtree(Expression subtree)

return constantExpression;
}
else
{
Expression<Func<object>> lambdaWithoutParameters = Expression.Lambda<Func<object>>(Expression.Convert(subtree, typeof(object)));
var compiledLambda = lambdaWithoutParameters.Compile();

object value = compiledLambda();
return Expression.Constant(value, subtree.Type);
try
{
return Expression.Constant(ExpressionProcessor.FindValue(subtree), subtree.Type);
}
catch (TargetInvocationException ex)
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Original code wraps expression in additional lambda to make it compile directly in Func<object> delegate.
But my tests show that direct expression compilation and DynamicInvoke works slightly faster. So just unwrap TargetInvocationException thrown by DynamicInvoke to behave as old code

BenchmarkDotNet=v0.13.1, OS=Windows 10.0.19043.1348 (21H1/May2021Update)
Intel Core i5-5200U CPU 2.20GHz (Broadwell), 1 CPU, 4 logical and 2 physical cores
.NET SDK=5.0.201
  [Host]     : .NET 5.0.4 (5.0.421.11614), X64 RyuJIT
  DefaultJob : .NET 5.0.4 (5.0.421.11614), X64 RyuJIT


|        Method |       Mean |     Error |    StdDev | Ratio | RatioSD |
|-------------- |-----------:|----------:|----------:|------:|--------:|
| DynamicInvoke | 183.670 us | 3.5535 us | 3.8022 us | 1.000 |    0.00 |
| WrapAndInvoke | 203.600 us | 1.3428 us | 1.1213 us | 1.106 |    0.02 |
|    Reflection |   1.020 us | 0.0078 us | 0.0070 us | 0.006 |    0.00 |

Source: https://gist.github.com/bahusoid/c68cb6b81f8dde9252d0cc67229136b4

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@hazzik hazzik Dec 1, 2021 •
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Reflection what is it? ok, I should have looked the code before asking.

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@hazzik hazzik Dec 9, 2021 •
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@bahusoid on my setup WrapAndInvoke is 18% faster than DynamicInvoke

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@bahusoid bahusoid Dec 9, 2021 •
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Hm... Interesting.. Maybe it's not about setup but target framework? I tested on .NET 5

{
throw ReflectHelper.UnwrapTargetInvocationException(ex);
}
}

Expand Down