Merge pull request #236 from servicetitan/upstream/optimize_bulk

Optimization: avoid Lambda JITing for typical case of invoking Bulk Set() with value

Author: alex-kulakov

Extensions/Xtensive.Orm.BulkOperations/BulkExtensions.cs

@@ -78,8 +78,14 @@ public static IUpdatable<T> Set<T, TResult>(this IUpdatable<T> query, Expression
     /// <returns>Instance of <see cref=" IUpdatable&lt;T&gt;"/>.</returns>
     [Pure]
     public static IUpdatable<T> Set<T, TResult>(this IQueryable<T> query, Expression<Func<T, TResult>> field,
-      TResult value) where T: IEntity =>
-      Set(query, field, a => value);
+      TResult value) where T: IEntity
+    {
+      // Manually constructed expression is simpler than `a => value`
+      var valueFunc = Expression.Lambda<Func<T, TResult>>(Expression.Constant(value, typeof(TResult)),
+        Expression.Parameter(typeof(T), "a"));
+
+      return Set(query, field, valueFunc);
+    }
 
     /// <summary>
     /// Executes bulk update of entities specified by the query.

Extensions/Xtensive.Orm.BulkOperations/Internals/AddValueContext.cs

@@ -1,4 +1,5 @@
-using System.Linq.Expressions;
+using System.Linq.Expressions;
+using Xtensive.Linq;
 using Xtensive.Orm.Model;
 using Xtensive.Sql.Dml;
 
@@ -16,5 +17,10 @@ internal class AddValueContext
     public FieldInfo Field { get; set; }
 
     public bool SubqueryExists { get; set; }
+
+    public object EvalLambdaBody() =>
+      Lambda.Body is ConstantExpression ce
+        ? ce.Value
+        : FastExpression.Lambda(Lambda.Body).Compile().DynamicInvoke();
   }
-}
+}

Extensions/Xtensive.Orm.BulkOperations/Internals/SetOperation.cs

@@ -136,7 +136,7 @@ private void AddComputedExpression(AddValueContext addContext)
       var sqlSelect = request.Query;
       SqlExpression ex = sqlSelect.OrderBy[0].Expression;
       parent.Bindings.AddRange(request.ParameterBindings);
-      
+
       if(parent.JoinedTableRef!=null)
         ex.AcceptVisitor(new ComputedExpressionSqlVisitor(sqlSelect.From, parent.JoinedTableRef));
 
@@ -146,10 +146,11 @@ private void AddComputedExpression(AddValueContext addContext)
     private void AddConstantValue(AddValueContext addContext)
     {
       SqlTableColumn column = SqlDml.TableColumn(addContext.Statement.Table, addContext.Field.Column.Name);
+      var constant = addContext.EvalLambdaBody();
       SqlExpression value;
-      object constant = FastExpression.Lambda(addContext.Lambda.Body).Compile().DynamicInvoke();
-      if (constant==null)
+      if (constant == null) {
         value = SqlDml.Null;
+      }
       else {
         QueryParameterBinding binding = parent.QueryBuilder.CreateParameterBinding(constant.GetType(), context => constant);
         parent.Bindings.Add(binding);
@@ -223,7 +224,8 @@ private void AddEntityValue(AddValueContext addContext)
         }
       }
       i = -1;
-      var entity = (IEntity) FastExpression.Lambda(addContext.Lambda.Body).Compile().DynamicInvoke();
+      var entity = (IEntity)addContext.EvalLambdaBody();
+
       foreach (ColumnInfo column in addContext.Field.Columns) {
         i++;
         SqlExpression value;