add [BatchSize] and pass thru to multi-row execute

src/Dapper.AOT.Analyzers/CodeAnalysis/DapperAnalyzer.cs

@@ -747,6 +747,7 @@ enum ParameterMode
             }
         }
 
+        int? batchSize = null;
         foreach (var attrib in methodAttribs)
         {
             if (IsDapperAttribute(attrib))
@@ -778,6 +779,12 @@ enum ParameterMode
                     case Types.CommandPropertyAttribute:
                         cmdPropsCount++;
                         break;
+                    case Types.BatchSizeAttribute:
+                        if (attrib.ConstructorArguments.Length == 1 && attrib.ConstructorArguments[0].Value is int batchTmp)
+                        {
+                            batchSize = batchTmp;
+                        }
+                        break;
                 }
             }
         }
@@ -806,8 +813,8 @@ enum ParameterMode
         }
 
 
-        return cmdProps.IsDefaultOrEmpty && rowCountHint <= 0 && rowCountHintMember is null
-            ? null : new(rowCountHint, rowCountHintMember?.Member.Name, cmdProps);
+        return cmdProps.IsDefaultOrEmpty && rowCountHint <= 0 && rowCountHintMember is null && batchSize is null
+            ? null : new(rowCountHint, rowCountHintMember?.Member.Name, batchSize, cmdProps);
     }
 
     internal static ImmutableArray<ElementMember>? SharedGetParametersToInclude(MemberMap? map, ref OperationFlags flags, string? sql, Action<Diagnostic>? reportDiagnostic, out SqlParseOutputFlags parseFlags)

src/Dapper.AOT.Analyzers/CodeAnalysis/DapperInterceptorGenerator.Multi.cs

@@ -44,6 +44,10 @@ void WriteMultiExecExpression(ITypeSymbol elementType, string castType)
             bool isAsync = flags.HasAny(OperationFlags.Async);
             sb.Append("Execute").Append(isAsync ? "Async" : "").Append("(");
             sb.Append("(").Append(castType).Append(")param!");
+            if (additionalCommandState?.BatchSize is { } batchSize)
+            {
+                sb.Append(", batchSize: ").Append(batchSize);
+            }
             if (isAsync && HasParam(methodParameters, "cancellationToken"))
             {
                 sb.Append(", cancellationToken: ").Append(Forward(methodParameters, "cancellationToken"));

src/Dapper.AOT.Analyzers/Internal/AdditionalCommandState.cs

@@ -35,6 +35,7 @@ public bool Equals(in CommandProperty other)
 internal sealed class AdditionalCommandState : IEquatable<AdditionalCommandState>
 {
     public readonly int RowCountHint;
+    public readonly int? BatchSize;
     public readonly string? RowCountHintMemberName;
     public readonly ImmutableArray<CommandProperty> CommandProperties;
 
@@ -72,7 +73,8 @@ private static AdditionalCommandState Combine(AdditionalCommandState inherited,
             countMember = null;
         }
 
-        return new(count, countMember, Concat(inherited.CommandProperties, overrides.CommandProperties));
+        return new(count, countMember, inherited.BatchSize ?? overrides.BatchSize,
+            Concat(inherited.CommandProperties, overrides.CommandProperties));
     }
 
     static ImmutableArray<CommandProperty> Concat(ImmutableArray<CommandProperty> x, ImmutableArray<CommandProperty> y)
@@ -85,10 +87,13 @@ static ImmutableArray<CommandProperty> Concat(ImmutableArray<CommandProperty> x,
         return builder.ToImmutable();
     }
 
-    internal AdditionalCommandState(int rowCountHint, string? rowCountHintMemberName, ImmutableArray<CommandProperty> commandProperties)
+    internal AdditionalCommandState(
+        int rowCountHint, string? rowCountHintMemberName, int? batchSize,
+        ImmutableArray<CommandProperty> commandProperties)
     {
         RowCountHint = rowCountHint;
         RowCountHintMemberName = rowCountHintMemberName;
+        BatchSize = batchSize;
         CommandProperties = commandProperties;
     }
 
@@ -98,7 +103,9 @@ internal AdditionalCommandState(int rowCountHint, string? rowCountHintMemberName
     bool IEquatable<AdditionalCommandState>.Equals(AdditionalCommandState other) => Equals(in other);
 
     public bool Equals(in AdditionalCommandState other)
-        => RowCountHint == other.RowCountHint && RowCountHintMemberName == other.RowCountHintMemberName
+        => RowCountHint == other.RowCountHint
+        && BatchSize == other.BatchSize
+        && RowCountHintMemberName == other.RowCountHintMemberName
         && ((CommandProperties.IsDefaultOrEmpty && other.CommandProperties.IsDefaultOrEmpty) || Equals(CommandProperties, other.CommandProperties));
 
     private static bool Equals(in ImmutableArray<CommandProperty> x, in ImmutableArray<CommandProperty> y)
@@ -136,6 +143,7 @@ static int GetHashCode(in ImmutableArray<CommandProperty> x)
     }
 
     public override int GetHashCode()
-        => (RowCountHint + (RowCountHintMemberName is null ? 0 : RowCountHintMemberName.GetHashCode()))
+        => (RowCountHint + BatchSize.GetValueOrDefault()
+        + (RowCountHintMemberName is null ? 0 : RowCountHintMemberName.GetHashCode()))
         ^ (CommandProperties.IsDefaultOrEmpty ? 0 : GetHashCode(in CommandProperties));
 }

src/Dapper.AOT.Analyzers/Internal/Types.cs

@@ -16,5 +16,6 @@ public const string
         IDynamicParameters = nameof(IDynamicParameters),
         SqlMapper = nameof(SqlMapper),
         SqlAttribute = nameof(SqlAttribute),
-        ExplicitConstructorAttribute = nameof(ExplicitConstructorAttribute);
+        ExplicitConstructorAttribute = nameof(ExplicitConstructorAttribute),
+        BatchSizeAttribute = nameof(BatchSizeAttribute);
 }

src/Dapper.AOT/BatchSizeAttribute.cs

@@ -0,0 +1,19 @@
+using System;
+using System.ComponentModel;
+using System.Diagnostics;
+
+namespace Dapper;
+
+/// <summary>
+/// Indicates the batch size to use when executing commands with a sequence of argument rows.
+/// </summary>
+[Conditional("DEBUG")] // not needed post-build, so: evaporate
+[ImmutableObject(true)]
+[AttributeUsage(AttributeTargets.Assembly | AttributeTargets.Module | AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Method, AllowMultiple = false)]
+public sealed class BatchSizeAttribute : Attribute
+{
+    /// <summary>
+    /// Indicates the batch size to use when executing commands with a sequence of argument row; a value of zero disables batch usage; a negative value uses a single batch for all rows.
+    /// </summary>
+    public BatchSizeAttribute(int batchSize) => _ = batchSize;
+}

test/Dapper.AOT.Test/Interceptors/BatchSize.input.cs

@@ -0,0 +1,23 @@
+using Dapper;
+using System.Data.Common;
+
+[module: DapperAot]
+
+public static class Foo
+{
+    [BatchSize(10)] // should be passed explicitly
+    static void SomeCode(DbConnection connection, string sql, string bar)
+    {
+        var objs = new[] { new { id = 12, bar }, new { id = 34, bar = "def" } };
+
+        connection.Execute("insert Foo (Id, Value) values (@id, @bar)", objs);
+    }
+
+    // no batch size, should be passed implicitly
+    static void SomeOtherCode(DbConnection connection, string sql, string bar)
+    {
+        var objs = new[] { new { id = 12, bar }, new { id = 34, bar = "def" } };
+
+        connection.Execute("insert Foo (Id, Value) values (@id, @bar)", objs);
+    }
+}

test/Dapper.AOT.Test/Interceptors/BatchSize.output.cs

@@ -0,0 +1,144 @@
+#nullable enable
+namespace Dapper.AOT // interceptors must be in a known namespace
+{
+    file static class DapperGeneratedInterceptors
+    {
+        [global::System.Runtime.CompilerServices.InterceptsLocationAttribute("Interceptors\\BatchSize.input.cs", 13, 20)]
+        internal static int Execute0(this global::System.Data.IDbConnection cnn, string sql, object? param, global::System.Data.IDbTransaction? transaction, int? commandTimeout, global::System.Data.CommandType? commandType)
+        {
+            // Execute, HasParameters, Text, KnownParameters
+            // takes parameter: global::<anonymous type: int id, string bar>[]
+            // parameter map: bar id
+            global::System.Diagnostics.Debug.Assert(!string.IsNullOrWhiteSpace(sql));
+            global::System.Diagnostics.Debug.Assert((commandType ?? global::Dapper.DapperAotExtensions.GetCommandType(sql)) == global::System.Data.CommandType.Text);
+            global::System.Diagnostics.Debug.Assert(param is not null);
+
+            return global::Dapper.DapperAotExtensions.Command(cnn, transaction, sql, global::System.Data.CommandType.Text, commandTimeout.GetValueOrDefault(), CommandFactory0.Instance).Execute((object?[])param!, batchSize: 10);
+
+        }
+
+        [global::System.Runtime.CompilerServices.InterceptsLocationAttribute("Interceptors\\BatchSize.input.cs", 21, 20)]
+        internal static int Execute1(this global::System.Data.IDbConnection cnn, string sql, object? param, global::System.Data.IDbTransaction? transaction, int? commandTimeout, global::System.Data.CommandType? commandType)
+        {
+            // Execute, HasParameters, Text, KnownParameters
+            // takes parameter: global::<anonymous type: int id, string bar>[]
+            // parameter map: bar id
+            global::System.Diagnostics.Debug.Assert(!string.IsNullOrWhiteSpace(sql));
+            global::System.Diagnostics.Debug.Assert((commandType ?? global::Dapper.DapperAotExtensions.GetCommandType(sql)) == global::System.Data.CommandType.Text);
+            global::System.Diagnostics.Debug.Assert(param is not null);
+
+            return global::Dapper.DapperAotExtensions.Command(cnn, transaction, sql, global::System.Data.CommandType.Text, commandTimeout.GetValueOrDefault(), CommandFactory1.Instance).Execute((object?[])param!);
+
+        }
+
+        private class CommonCommandFactory<T> : global::Dapper.CommandFactory<T>
+        {
+            public override global::System.Data.Common.DbCommand GetCommand(global::System.Data.Common.DbConnection connection, string sql, global::System.Data.CommandType commandType, T args)
+            {
+                var cmd = base.GetCommand(connection, sql, commandType, args);
+                // apply special per-provider command initialization logic for OracleCommand
+                if (cmd is global::Oracle.ManagedDataAccess.Client.OracleCommand cmd0)
+                {
+                    cmd0.BindByName = true;
+                    cmd0.InitialLONGFetchSize = -1;
+
+                }
+                return cmd;
+            }
+
+        }
+
+        private static readonly CommonCommandFactory<object?> DefaultCommandFactory = new();
+
+        private sealed class CommandFactory0 : CommonCommandFactory<object?> // <anonymous type: int id, string bar>
+        {
+            internal static readonly CommandFactory0 Instance = new();
+            public override void AddParameters(in global::Dapper.UnifiedCommand cmd, object? args)
+            {
+                var typed = Cast(args, static () => new { id = default(int), bar = default(string)! }); // expected shape
+                var ps = cmd.Parameters;
+                global::System.Data.Common.DbParameter p;
+                p = cmd.CreateParameter();
+                p.ParameterName = "id";
+                p.DbType = global::System.Data.DbType.Int32;
+                p.Direction = global::System.Data.ParameterDirection.Input;
+                p.Value = AsValue(typed.id);
+                ps.Add(p);
+
+                p = cmd.CreateParameter();
+                p.ParameterName = "bar";
+                p.DbType = global::System.Data.DbType.String;
+                p.Size = -1;
+                p.Direction = global::System.Data.ParameterDirection.Input;
+                p.Value = AsValue(typed.bar);
+                ps.Add(p);
+
+            }
+            public override void UpdateParameters(in global::Dapper.UnifiedCommand cmd, object? args)
+            {
+                var typed = Cast(args, static () => new { id = default(int), bar = default(string)! }); // expected shape
+                var ps = cmd.Parameters;
+                ps[0].Value = AsValue(typed.id);
+                ps[1].Value = AsValue(typed.bar);
+
+            }
+            public override bool CanPrepare => true;
+
+        }
+
+        private sealed class CommandFactory1 : CommonCommandFactory<object?> // <anonymous type: int id, string bar>
+        {
+            internal static readonly CommandFactory1 Instance = new();
+            public override void AddParameters(in global::Dapper.UnifiedCommand cmd, object? args)
+            {
+                var typed = Cast(args, static () => new { id = default(int), bar = default(string)! }); // expected shape
+                var ps = cmd.Parameters;
+                global::System.Data.Common.DbParameter p;
+                p = cmd.CreateParameter();
+                p.ParameterName = "id";
+                p.DbType = global::System.Data.DbType.Int32;
+                p.Direction = global::System.Data.ParameterDirection.Input;
+                p.Value = AsValue(typed.id);
+                ps.Add(p);
+
+                p = cmd.CreateParameter();
+                p.ParameterName = "bar";
+                p.DbType = global::System.Data.DbType.String;
+                p.Size = -1;
+                p.Direction = global::System.Data.ParameterDirection.Input;
+                p.Value = AsValue(typed.bar);
+                ps.Add(p);
+
+            }
+            public override void UpdateParameters(in global::Dapper.UnifiedCommand cmd, object? args)
+            {
+                var typed = Cast(args, static () => new { id = default(int), bar = default(string)! }); // expected shape
+                var ps = cmd.Parameters;
+                ps[0].Value = AsValue(typed.id);
+                ps[1].Value = AsValue(typed.bar);
+
+            }
+            public override bool CanPrepare => true;
+
+        }
+
+
+    }
+}
+namespace System.Runtime.CompilerServices
+{
+    // this type is needed by the compiler to implement interceptors - it doesn't need to
+    // come from the runtime itself, though
+
+    [global::System.Diagnostics.Conditional("DEBUG")] // not needed post-build, so: evaporate
+    [global::System.AttributeUsage(global::System.AttributeTargets.Method, AllowMultiple = true)]
+    sealed file class InterceptsLocationAttribute : global::System.Attribute
+    {
+        public InterceptsLocationAttribute(string path, int lineNumber, int columnNumber)
+        {
+            _ = path;
+            _ = lineNumber;
+            _ = columnNumber;
+        }
+    }
+}