Bind named parameters by the name the statement declares

Directory.Build.props

@@ -39,7 +39,12 @@
   </PropertyGroup>
 
   <PropertyGroup>
-    <BuildType>ManagedOnly</BuildType>
+    <BuildType Condition="'$(BuildType)' == ''">ManagedOnly</BuildType>
+    <DuckDbVersion Condition="'$(DuckDbVersion)' == ''">1.5.5</DuckDbVersion>
+    <!-- Outside obj, because the SDK puts obj\** in DefaultItemExcludes and an item glob under it
+         silently matches nothing. The version in the path makes the directory the cache key, so a
+         bump lands in a fresh folder and cannot pick up the previous engine. -->
+    <DuckDbNativeRoot Condition="'$(DuckDbNativeRoot)' == ''">$(MSBuildThisFileDirectory)artifacts\natives\$(DuckDbVersion)\</DuckDbNativeRoot>
     <NoNativeText>This package does not include a copy of the native DuckDB library.</NoNativeText>
   </PropertyGroup>
   <PropertyGroup Condition="'$(BuildType)' == 'Full' ">

DuckDB.NET.Benchmarks/Benchmarks.csproj

@@ -20,14 +20,4 @@
     <ProjectReference Include="..\DuckDB.NET.Bindings\Bindings.csproj" />
   </ItemGroup>
 
-  <!-- Copy the already-downloaded native DuckDB library into the benchmark output so it can be
-       loaded via runtimes/{rid}/native/. -->
-  <ItemGroup>
-    <None Include="..\DuckDB.NET.Bindings\obj\runtimes\**\*.dll;..\DuckDB.NET.Bindings\obj\runtimes\**\*.so;..\DuckDB.NET.Bindings\obj\runtimes\**\*.dylib;">
-      <Visible>false</Visible>
-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-      <Link>runtimes\%(RecursiveDir)\%(FileName)%(Extension)</Link>
-    </None>
-  </ItemGroup>
-
 </Project>

DuckDB.NET.Benchmarks/ParameterBindingBenchmark.cs

@@ -0,0 +1,86 @@
+using System.Text;
+using BenchmarkDotNet.Attributes;
+using DuckDB.NET.Data;
+
+namespace DuckDB.NET.Benchmarks;
+
+[MemoryDiagnoser]
+public class ParameterBindingBenchmark
+{
+    private DuckDBConnection connection = null!;
+    private DuckDBCommand exact = null!;
+    private DuckDBCommand prefixed = null!;
+    private DuckDBCommand positional = null!;
+
+    [Params(1, 8, 32)]
+    public int ParameterCount { get; set; }
+
+    [GlobalSetup]
+    public void Setup()
+    {
+        connection = new DuckDBConnection("DataSource=:memory:");
+        connection.Open();
+
+        exact = BuildNamed("");
+        prefixed = BuildNamed("$");
+        positional = BuildPositional();
+    }
+
+    [GlobalCleanup]
+    public void Cleanup()
+    {
+        exact.Dispose();
+        prefixed.Dispose();
+        positional.Dispose();
+        connection.Dispose();
+    }
+
+    [Benchmark(Baseline = true)]
+    public object? NamedExact() => exact.ExecuteScalar();
+
+    [Benchmark]
+    public object? NamedPrefixed() => prefixed.ExecuteScalar();
+
+    [Benchmark]
+    public object? Positional() => positional.ExecuteScalar();
+
+    private DuckDBCommand BuildNamed(string parameterNamePrefix)
+    {
+        var command = connection.CreateCommand();
+        var sql = new StringBuilder("SELECT ");
+
+        for (var i = 0; i < ParameterCount; i++)
+        {
+            if (i > 0)
+            {
+                sql.Append(" + ");
+            }
+
+            sql.Append("$p").Append(i).Append("::INT");
+            command.Parameters.Add(new DuckDBParameter($"{parameterNamePrefix}p{i}", i));
+        }
+
+        command.CommandText = sql.ToString();
+        return command;
+    }
+
+    private DuckDBCommand BuildPositional()
+    {
+        var command = connection.CreateCommand();
+        var sql = new StringBuilder("SELECT ");
+
+        for (var i = 0; i < ParameterCount; i++)
+        {
+            if (i > 0)
+            {
+                sql.Append(" + ");
+            }
+
+            sql.Append("?::INT");
+            command.Parameters.Add(new DuckDBParameter(i));
+        }
+
+        command.CommandText = sql.ToString();
+        return command;
+    }
+}

DuckDB.NET.Benchmarks/Program.cs

@@ -11,5 +11,5 @@
     .AddJob(Job.Default.WithToolchain(InProcessEmitToolchain.Instance));
 
 BenchmarkSwitcher
-    .FromTypes([typeof(AppenderBenchmark), typeof(MappedAppenderBenchmark)])
+    .FromTypes([typeof(AppenderBenchmark), typeof(MappedAppenderBenchmark), typeof(ParameterBindingBenchmark)])
     .Run(args, config);

DuckDB.NET.Bindings/Bindings.csproj

@@ -3,15 +3,15 @@
   <PropertyGroup>
     <Description>DuckDB Bindings for C#.</Description>
     <PackageReleaseNotes>
-- Updated to DuckDB v1.5.5
+- Updated to DuckDB v$(DuckDbVersion)
 
 New features:
 - Added bindings for the Arrow C Data Interface (duckdb_to_arrow_schema, duckdb_data_chunk_to_arrow, duckdb_result_get_arrow_options)
 - Added bindings for error data (duckdb_appender_error_data, duckdb_error_data_error_type)
     </PackageReleaseNotes>
     <RootNamespace>DuckDB.NET.Native</RootNamespace>
     <RuntimeIdentifiers>win-x64;win-arm64;linux-x64;linux-arm64;osx</RuntimeIdentifiers>
-    <DuckDbArtifactRoot Condition=" '$(DuckDbArtifactRoot)' == '' ">https://github.com/duckdb/duckdb/releases/download/v1.5.5</DuckDbArtifactRoot>
+    <DuckDbArtifactRoot Condition=" '$(DuckDbArtifactRoot)' == '' ">https://github.com/duckdb/duckdb/releases/download/v$(DuckDbVersion)</DuckDbArtifactRoot>
     <SignAssembly>True</SignAssembly>
     <AssemblyOriginatorKeyFile>..\keyPair.snk</AssemblyOriginatorKeyFile>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
@@ -23,7 +23,16 @@ New features:
   </PropertyGroup>
 
   <!-- Download and include the native libraries into the NuGet package-->
-  <Target Name="DownloadNativeLibs" BeforeTargets="GenerateAdditionalSources" Condition="'$(BuildType)' == 'Full' AND '$(TargetFramework)' == '$([System.String]::Copy($(TargetFrameworks)).Split(%27;%27)[0])'">
+  <!-- Outer build only. The inner per-framework builds would otherwise race each other for the same
+       zip, and DispatchToInnerBuilds below makes the outer finish downloading before they start. -->
+  <PropertyGroup>
+    <!-- Only the Full package ships the engine, but every project that runs needs it beside the
+         assembly, so the copy is unconditional and only packing is gated. -->
+    <_PackDuckDbNatives Condition="'$(BuildType)' == 'Full' ">true</_PackDuckDbNatives>
+    <_PackDuckDbNatives Condition="'$(_PackDuckDbNatives)' == ''">false</_PackDuckDbNatives>
+  </PropertyGroup>
+
+  <Target Name="DownloadNativeLibs" Condition="'$(TargetFramework)' == '' ">
     <ItemGroup Condition="'$(NightlyBuild)' != 'true'">
       <_NativeLib Include="win-x64" LibUrl="$(DuckDbArtifactRoot)/libduckdb-windows-amd64.zip" />
       <_NativeLib Include="win-arm64" LibUrl="$(DuckDbArtifactRoot)/libduckdb-windows-arm64.zip" />
@@ -36,20 +45,29 @@ New features:
       <_NativeLib Include="linux-x64" LibUrl="$(DuckDbArtifactRoot)/duckdb-binaries-linux-amd64.zip" InnerZipName="libduckdb-linux-amd64.zip" Condition="$([MSBuild]::IsOSPlatform('Linux'))" />
       <_NativeLib Include="osx" LibUrl="$(DuckDbArtifactRoot)/duckdb-binaries-osx.zip" InnerZipName="libduckdb-osx-universal.zip" Condition="$([MSBuild]::IsOSPlatform('OSX'))" />
     </ItemGroup>
-    <MSBuild Projects="DownloadNativeLibs.targets" Properties="Rid=%(_NativeLib.Identity);LibUrl=%(_NativeLib.LibUrl);InnerZipName=%(_NativeLib.InnerZipName)" />
+    <MSBuild Projects="DownloadNativeLibs.targets" Properties="Rid=%(_NativeLib.Identity);LibUrl=%(_NativeLib.LibUrl);InnerZipName=%(_NativeLib.InnerZipName);DuckDbVersion=$(DuckDbVersion);DuckDbNativeRoot=$(DuckDbNativeRoot)" />
   </Target>
   <Target Name="CleanNativeLibs" BeforeTargets="Clean" Condition="'$(BuildType)' == 'Full' ">
-    <RemoveDir Directories="obj\runtimes" />
+    <RemoveDir Directories="$(DuckDbNativeRoot)" />
   </Target>
-  <ItemGroup Condition="'$(BuildType)' == 'Full' ">
-    <None Include="obj\runtimes\**\*.dll;obj\runtimes\**\*.so;obj\runtimes\**\*.dylib;">
+  <!-- Content, not None, and in the project body rather than a target: Content items flow across a
+       ProjectReference, so every consumer gets the engine from its reference alone. The glob works
+       here only because DuckDbNativeRoot sits outside obj, which DefaultItemExcludes would hide. -->
+  <ItemGroup>
+    <Content Include="$(DuckDbNativeRoot)**\*.dll;$(DuckDbNativeRoot)**\*.so;$(DuckDbNativeRoot)**\*.dylib">
       <Visible>false</Visible>
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-      <Pack>true</Pack>
+      <Pack>$(_PackDuckDbNatives)</Pack>
       <PackagePath>\runtimes</PackagePath>
-      <Link>runtimes\%(RecursiveDir)\%(FileName)%(Extension)</Link>
-    </None>
+      <Link>runtimes\%(RecursiveDir)%(FileName)%(Extension)</Link>
+    </Content>
   </ItemGroup>
+
+  <!-- Restore is the only phase before evaluation, and the glob above expands during evaluation.
+       NuGet runs this target once per project for a solution restore and a single-project restore
+       alike; the public Restore target only runs on the project the command names. -->
+  <Target Name="EnsureDuckDbNativeLibs" AfterTargets="_GenerateRestoreGraphProjectEntry"
+          DependsOnTargets="DownloadNativeLibs" />
   <ItemGroup Condition="'$(CI)' == 'true'">
     <PackageReference Include="GitVersion.MsBuild" Version="6.4.0" PrivateAssets="all" />
   </ItemGroup>

DuckDB.NET.Bindings/DownloadNativeLibs.targets

@@ -1,47 +1,77 @@
-<Project DefaultTargets="DownloadReleaseNatives;DownloadNightlyNatives">
-
-  <!-- Release: download lib zip directly -->
-  <Target Name="DownloadReleaseNatives"
-          Condition="!Exists('$(MSBuildProjectDirectory)\obj\runtimes\$(Rid)\native') AND '$(InnerZipName)' == ''">
-    <PropertyGroup>
-      <NativeZipPath>$(MSBuildProjectDirectory)\obj\runtimes\$(Rid)\native.zip</NativeZipPath>
-    </PropertyGroup>
-    <MakeDir Directories="$(MSBuildProjectDirectory)\obj\runtimes\$(Rid)\native" />
-    <Delete Files="$(NativeZipPath)"
-            Condition="Exists('$(NativeZipPath)')"
-            ContinueOnError="true"/>
-    <DownloadFile
-            DestinationFolder="$(MSBuildProjectDirectory)\obj\runtimes\$(Rid)"
-            SourceUrl="$(LibUrl)"
-            Retries="5"
-            RetryDelayMilliseconds="1000"
-            DestinationFileName="native.zip"/>
-    <Unzip DestinationFolder="$(MSBuildProjectDirectory)\obj\runtimes\$(Rid)\native"
-           SourceFiles="$(NativeZipPath)"/>
-    <Delete Files="$(NativeZipPath)"/>
+<Project DefaultTargets="DownloadNatives">
+
+  <PropertyGroup>
+    <RidDir>$(DuckDbNativeRoot)$(Rid)</RidDir>
+    <NativeDir>$(RidDir)\native</NativeDir>
+    <NativeZipPath>$(RidDir)\native.zip</NativeZipPath>
+    <TempExtractPath>$(RidDir)\temp</TempExtractPath>
+    <NativeInputsCacheFile>$(RidDir)\duckdb.inputs.cache</NativeInputsCacheFile>
+    <NativeDownloadCacheFile>$(RidDir)\duckdb.download.cache</NativeDownloadCacheFile>
+  </PropertyGroup>
+
+  <!-- This file is invoked as a project, not imported, and it carries no Sdk attribute, so it never
+       auto-imports Directory.Build.props. Every property below arrives from the caller, and an unset
+       DuckDbVersion would key the cache stamp on an empty string. -->
+  <Target Name="_ValidateNativeDownloadInputs">
+    <Error Text="Rid and LibUrl must be supplied by the caller."
+           Condition="'$(Rid)' == '' OR '$(LibUrl)' == ''" />
+    <Error Text="DuckDbVersion must be supplied by the caller so the cache stamp is keyed on a version."
+           Condition="('$(DuckDbVersion)' == '' OR '$(DuckDbNativeRoot)' == '') AND '$(InnerZipName)' == ''" />
+  </Target>
+
+  <!-- The URL carries the version, so writing it to a cache file makes a version change move that
+       file's timestamp and nothing else does. WriteOnlyWhenDifferent is what holds the timestamp
+       still when the version has not moved. This is how the SDK lets a value, rather than a source
+       file, drive incrementality: see CreateGeneratedAssemblyInfoInputsCacheFile in
+       Microsoft.NET.GenerateAssemblyInfo.targets. -->
+  <Target Name="_CreateNativeInputsCacheFile" DependsOnTargets="_ValidateNativeDownloadInputs">
+    <MakeDir Directories="$(RidDir)" />
+    <WriteLinesToFile Lines="$(LibUrl)"
+                      File="$(NativeInputsCacheFile)"
+                      Overwrite="true"
+                      WriteOnlyWhenDifferent="true" />
   </Target>
 
-  <!-- Nightly: download outer zip, extract inner lib zip -->
-  <Target Name="DownloadNightlyNatives"
-          Condition="!Exists('$(MSBuildProjectDirectory)\obj\runtimes\$(Rid)\native') AND '$(InnerZipName)' != ''">
-    <PropertyGroup>
-      <NativeZipPath>$(MSBuildProjectDirectory)\obj\runtimes\$(Rid)\native.zip</NativeZipPath>
-      <TempExtractPath>$(MSBuildProjectDirectory)\obj\runtimes\$(Rid)\temp</TempExtractPath>
-    </PropertyGroup>
-    <MakeDir Directories="$(MSBuildProjectDirectory)\obj\runtimes\$(Rid)\native" />
-    <Delete Files="$(NativeZipPath)" Condition="Exists('$(NativeZipPath)')" ContinueOnError="true"/>
-    <DownloadFile
-            DestinationFolder="$(MSBuildProjectDirectory)\obj\runtimes\$(Rid)"
-            SourceUrl="$(LibUrl)"
-            Retries="5"
-            RetryDelayMilliseconds="1000"
-            DestinationFileName="native.zip"/>
-    <Unzip DestinationFolder="$(TempExtractPath)"
-           SourceFiles="$(NativeZipPath)"/>
-    <Unzip DestinationFolder="$(MSBuildProjectDirectory)\obj\runtimes\$(Rid)\native"
-           SourceFiles="$(TempExtractPath)\$(InnerZipName)"/>
-    <RemoveDir Directories="$(TempExtractPath)" />
-    <Delete Files="$(NativeZipPath)"/>
+  <!-- A release artifact is a zip holding the library. A nightly artifact is a zip holding one
+       per-platform zip that holds the library, which is the only difference between the two. -->
+  <Target Name="DownloadNatives"
+          DependsOnTargets="_CreateNativeInputsCacheFile"
+          Inputs="$(NativeInputsCacheFile)"
+          Outputs="$(NativeDownloadCacheFile)">
+    <Delete Files="$(NativeZipPath)" Condition="Exists('$(NativeZipPath)')" ContinueOnError="true" />
+
+    <!-- Fetch before touching the installed payload. Clearing first would leave the build with no
+         native library at all whenever the download fails. -->
+    <DownloadFile DestinationFolder="$(RidDir)"
+                  SourceUrl="$(LibUrl)"
+                  Retries="5"
+                  RetryDelayMilliseconds="1000"
+                  DestinationFileName="native.zip" />
+
+    <!-- The archive is in hand, so the superseded payload can go. Unzipping over the old files
+         would keep whatever the new release no longer ships. -->
+    <RemoveDir Directories="$(NativeDir)" />
+    <MakeDir Directories="$(NativeDir)" />
+
+    <Unzip DestinationFolder="$(NativeDir)" SourceFiles="$(NativeZipPath)"
+           Condition="'$(InnerZipName)' == ''" />
+
+    <Unzip DestinationFolder="$(TempExtractPath)" SourceFiles="$(NativeZipPath)"
+           Condition="'$(InnerZipName)' != ''" />
+    <Unzip DestinationFolder="$(NativeDir)" SourceFiles="$(TempExtractPath)\$(InnerZipName)"
+           Condition="'$(InnerZipName)' != ''" />
+    <RemoveDir Directories="$(TempExtractPath)" Condition="'$(InnerZipName)' != ''" />
+
+    <Delete Files="$(NativeZipPath)" />
+
+    <!-- Written last. A failure anywhere above leaves this file absent or older than the inputs
+         cache, so the next build retries instead of treating a half-populated directory as a
+         complete one. -->
+    <WriteLinesToFile File="$(NativeDownloadCacheFile)" Lines="$(LibUrl)" Overwrite="true" />
+
+    <ItemGroup>
+      <FileWrites Include="$(NativeInputsCacheFile);$(NativeDownloadCacheFile)" />
+    </ItemGroup>
   </Target>
 
 </Project>