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Query: Fix #4588 - Query :: SelectMany-GroupJoin-DefaultIfEmpty isn't…
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… being lifted into SQL for some complex queries, resulting in extensive client-side evaluation.

Adds relational GroupJoin/DefaultIfEmpty elimination.
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@anpete
anpete committed Sep 23, 2016
1 parent ae02086 commit 757e6d4
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Showing 17 changed files with 627 additions and 364 deletions.
44 changes: 40 additions & 4 deletions ...ntityFrameworkCore.Relational/Query/ExpressionVisitors/SqlTranslatingExpressionVisitor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -212,7 +212,8 @@ var structuralComparisonExpression
var leftExpression = Visit(expression.Left);
var rightExpression = Visit(expression.Right);

return leftExpression != null && rightExpression != null
return leftExpression != null
&& rightExpression != null
? Expression.MakeBinary(
expression.NodeType,
leftExpression,
Expand Down Expand Up @@ -252,6 +253,7 @@ protected override Expression VisitConditional(ConditionalExpression expression)
var ifTrue = Visit(expression.IfTrue);
var ifFalse = Visit(expression.IfFalse);

// ReSharper disable once ConditionIsAlwaysTrueOrFalse
if (test != null
&& ifTrue != null
&& ifFalse != null)
Expand Down Expand Up @@ -991,9 +993,21 @@ protected override Expression VisitExtension(Expression expression)
var nullConditionalExpression
= expression as NullConditionalExpression;

return nullConditionalExpression != null
? Visit(nullConditionalExpression.AccessOperation)
: base.VisitExtension(expression);
if (nullConditionalExpression != null)
{
var newAccessOperation = Visit(nullConditionalExpression.AccessOperation);

if (newAccessOperation != null
&& newAccessOperation.Type != nullConditionalExpression.Type)
{
newAccessOperation
= Expression.Convert(newAccessOperation, nullConditionalExpression.Type);
}

return newAccessOperation;
}

return base.VisitExtension(expression);
}

/// <summary>
Expand All @@ -1007,6 +1021,28 @@ protected override Expression VisitQuerySourceReference(QuerySourceReferenceExpr
{
Check.NotNull(expression, nameof(expression));

if (!_inProjection)
{
var joinClause
= expression.ReferencedQuerySource as JoinClause;

if (joinClause != null)
{
var entityType
= _queryModelVisitor.QueryCompilationContext.Model
.FindEntityType(joinClause.ItemType);

if (entityType != null)
{
return Visit(
EntityQueryModelVisitor.CreatePropertyExpression(
expression, entityType.FindPrimaryKey().Properties[0]));
}

return null;
}
}

var selector
= ((expression.ReferencedQuerySource as FromClauseBase)
?.FromExpression as SubQueryExpression)
Expand Down
14 changes: 13 additions & 1 deletion src/Microsoft.EntityFrameworkCore.Relational/Query/Expressions/SelectExpression.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -476,14 +476,26 @@ public virtual int AddToProjection([NotNull] Expression expression)
public virtual int AddToProjection([NotNull] Expression expression, bool resetProjectStar)
{
Check.NotNull(expression, nameof(expression));

if (expression.NodeType == ExpressionType.Convert)
{
var unaryExpression = (UnaryExpression)expression;

if (unaryExpression.Type.UnwrapNullableType()
== unaryExpression.Operand.Type)
{
expression = unaryExpression.Operand;
}
}

var columnExpression = expression as ColumnExpression;
var aliasExpression = expression as AliasExpression;

if (columnExpression != null)
{
return AddToProjection(columnExpression);
}

var aliasExpression = expression as AliasExpression;

if (aliasExpression != null)
{
Expand Down
11 changes: 7 additions & 4 deletions ...icrosoft.EntityFrameworkCore.Relational/Query/Internal/RelationalResultOperatorHandler.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -680,10 +680,11 @@ private static Expression HandleSkip(HandlerContext handlerContext)

private static Expression HandleSum(HandlerContext handlerContext)
{
if (!handlerContext.QueryModelVisitor.RequiresClientProjection)
if (!handlerContext.QueryModelVisitor.RequiresClientProjection
&& handlerContext.SelectExpression.Projection.Count == 1)
{
var sumExpression
= new SumExpression(handlerContext.SelectExpression.Projection.Single());
= new SumExpression(handlerContext.SelectExpression.Projection.First());

handlerContext.SelectExpression.SetProjectionExpression(sumExpression);

Expand All @@ -699,12 +700,14 @@ private static Expression HandleTake(HandlerContext handlerContext)
{
var takeResultOperator = (TakeResultOperator)handlerContext.ResultOperator;

var sqlTranslatingExpressionVisitor = handlerContext.CreateSqlTranslatingVisitor(bindParentQueries: true);
var sqlTranslatingExpressionVisitor
= handlerContext.CreateSqlTranslatingVisitor(bindParentQueries: true);

var limit = sqlTranslatingExpressionVisitor.Visit(takeResultOperator.Count);

if (limit != null)
{
handlerContext.SelectExpression.Limit = takeResultOperator.Count;
handlerContext.SelectExpression.Limit = limit;

return handlerContext.EvalOnServer;
}
Expand Down
146 changes: 111 additions & 35 deletions src/Microsoft.EntityFrameworkCore.Relational/Query/RelationalQueryModelVisitor.cs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,8 @@
using Remotion.Linq;
using Remotion.Linq.Clauses;
using Remotion.Linq.Clauses.Expressions;
using Remotion.Linq.Clauses.ExpressionVisitors;
using Remotion.Linq.Clauses.ResultOperators;

namespace Microsoft.EntityFrameworkCore.Query
{
Expand Down Expand Up @@ -243,7 +245,7 @@ public virtual void RegisterSubQueryVisitor(
Check.NotNull(querySource, nameof(querySource));
Check.NotNull(queryModelVisitor, nameof(queryModelVisitor));

_subQueryModelVisitorsBySource.Add(querySource, queryModelVisitor);
_subQueryModelVisitorsBySource[querySource] = queryModelVisitor;
}

/// <summary>
Expand Down Expand Up @@ -341,12 +343,13 @@ protected override void IncludeNavigations(
Check.NotNull(includeSpecification, nameof(includeSpecification));
Check.NotNull(resultType, nameof(resultType));

var includeExpressionVisitor = _includeExpressionVisitorFactory.Create(
includeSpecification.QuerySource,
includeSpecification.NavigationPath,
QueryCompilationContext,
_navigationIndexMap[includeSpecification],
querySourceRequiresTracking);
var includeExpressionVisitor
= _includeExpressionVisitorFactory.Create(
includeSpecification.QuerySource,
includeSpecification.NavigationPath,
QueryCompilationContext,
_navigationIndexMap[includeSpecification],
querySourceRequiresTracking);

Expression = includeExpressionVisitor.Visit(Expression);
}
Expand Down Expand Up @@ -510,15 +513,12 @@ var fromQuerySourceReferenceExpression
private bool CanFlattenSelectMany()
{
var selectManyExpression = Expression as MethodCallExpression;
if (selectManyExpression == null
|| !selectManyExpression.Method.MethodIsClosedFormOf(LinqOperatorProvider.SelectMany)
|| !IsShapedQueryExpression(selectManyExpression.Arguments[0] as MethodCallExpression, innerShapedQuery: false)
|| !IsShapedQueryExpression((selectManyExpression.Arguments[1] as LambdaExpression)?.Body as MethodCallExpression, innerShapedQuery: true))
{
return false;
}

return true;
return selectManyExpression != null
&& selectManyExpression.Method.MethodIsClosedFormOf(LinqOperatorProvider.SelectMany)
&& IsShapedQueryExpression(selectManyExpression.Arguments[0] as MethodCallExpression, innerShapedQuery: false)
&& IsShapedQueryExpression((selectManyExpression.Arguments[1] as LambdaExpression)
?.Body as MethodCallExpression, innerShapedQuery: true);
}

private bool IsShapedQueryExpression(MethodCallExpression shapedQueryExpression, bool innerShapedQuery)
Expand All @@ -538,18 +538,14 @@ private bool IsShapedQueryExpression(MethodCallExpression shapedQueryExpression,
}
}

if (shapedQueryExpression == null || shapedQueryExpression.Arguments.Count != 3)
if (shapedQueryExpression.Arguments.Count != 3)
{
return false;
}

var shaper = shapedQueryExpression.Arguments[2] as ConstantExpression;
if (shaper == null || !(shaper.Value is Shaper))
{
return false;
}

return true;
return shaper?.Value is Shaper;
}

/// <summary>
Expand Down Expand Up @@ -627,7 +623,7 @@ public override void VisitGroupJoinClause(
index,
() => base.VisitGroupJoinClause(groupJoinClause, queryModel, index),
LinqOperatorProvider.GroupJoin,
outerJoin: true);
groupJoin: true);
}

/// <summary>
Expand All @@ -638,14 +634,14 @@ public override void VisitGroupJoinClause(
/// <param name="index"> Index of the node being visited. </param>
/// <param name="baseVisitAction"> The base visit action. </param>
/// <param name="operatorToFlatten"> The operator to flatten. </param>
/// <param name="outerJoin"> true if an outer join should be performed. </param>
/// <param name="groupJoin"> true if an outer join should be performed. </param>
protected virtual void OptimizeJoinClause(
[NotNull] JoinClause joinClause,
[NotNull] QueryModel queryModel,
int index,
[NotNull] Action baseVisitAction,
[NotNull] MethodInfo operatorToFlatten,
bool outerJoin = false)
bool groupJoin = false)
{
Check.NotNull(joinClause, nameof(joinClause));
Check.NotNull(queryModel, nameof(queryModel));
Expand All @@ -664,11 +660,14 @@ var previousSelectExpression
var previousSelectProjectionCount
= previousSelectExpression?.Projection.Count ?? -1;

var previousParameter = CurrentParameter;
var previousMapping = SnapshotQuerySourceMapping(queryModel);

baseVisitAction();

if (!RequiresClientSelectMany
&& previousSelectExpression != null
&& (!operatorToFlatten.MethodIsClosedFormOf(LinqOperatorProvider.GroupJoin)
&& (!groupJoin
|| CanFlattenGroupJoin()))
{
var selectExpression = TryGetQuery(joinClause);
Expand Down Expand Up @@ -700,13 +699,13 @@ var projection
: Enumerable.Empty<Expression>();

var joinExpression
= !outerJoin
= !groupJoin
? previousSelectExpression.AddInnerJoin(tableExpression, projection)
: previousSelectExpression.AddLeftOuterJoin(tableExpression, projection);

joinExpression.Predicate = predicate;

if (outerJoin)
if (groupJoin)
{
var outerJoinOrderingExtractor = new OuterJoinOrderingExtractor();

Expand All @@ -717,6 +716,61 @@ var joinExpression
previousSelectExpression
.AddToOrderBy(new Ordering(expression, OrderingDirection.Asc));
}

var additionalFromClause
= queryModel.BodyClauses.ElementAtOrDefault(index + 1)
as AdditionalFromClause;

var subQueryModel
= (additionalFromClause?.FromExpression as SubQueryExpression)?.QueryModel;

if (subQueryModel != null
&& subQueryModel.ResultOperators.Count == 1
&& subQueryModel.ResultOperators[0] is DefaultIfEmptyResultOperator)
{
var groupJoinClause
= (subQueryModel.MainFromClause.FromExpression as QuerySourceReferenceExpression)
?.ReferencedQuerySource as GroupJoinClause;

if (groupJoinClause?.JoinClause == joinClause
&& queryModel.CountQuerySourceReferences(groupJoinClause) == 1)
{
queryModel.BodyClauses.RemoveAt(index + 1);

var querySourceMapping = new QuerySourceMapping();

querySourceMapping.AddMapping(
additionalFromClause,
new QuerySourceReferenceExpression(joinClause));

queryModel.TransformExpressions(e =>
ReferenceReplacingExpressionVisitor
.ReplaceClauseReferences(
e,
querySourceMapping,
throwOnUnmappedReferences: false));

Expression = ((MethodCallExpression)Expression).Arguments[0];

CurrentParameter = previousParameter;

foreach (var mapping in previousMapping)
{
QueryCompilationContext.QuerySourceMapping
.ReplaceMapping(mapping.Key, mapping.Value);
}

var previousProjectionCount = previousSelectExpression.Projection.Count;

base.VisitJoinClause(joinClause, queryModel, index);

previousSelectExpression.RemoveRangeFromProjection(previousProjectionCount);

QueriesBySource.Remove(joinClause);

operatorToFlatten = LinqOperatorProvider.Join;
}
}
}

Expression
Expand All @@ -739,18 +793,40 @@ var joinExpression
}
}

private bool CanFlattenGroupJoin()
private Dictionary<IQuerySource, Expression> SnapshotQuerySourceMapping(QueryModel queryModel)
{
var groupJoinExpression = Expression as MethodCallExpression;
if (groupJoinExpression == null
|| !groupJoinExpression.Method.MethodIsClosedFormOf(LinqOperatorProvider.GroupJoin)
|| !IsShapedQueryExpression(groupJoinExpression.Arguments[0] as MethodCallExpression, innerShapedQuery: false)
|| !IsShapedQueryExpression(groupJoinExpression.Arguments[1] as MethodCallExpression, innerShapedQuery: true))
var previousMapping
= new Dictionary<IQuerySource, Expression>
{
{
queryModel.MainFromClause,
QueryCompilationContext.QuerySourceMapping
.GetExpression(queryModel.MainFromClause)
}
};

foreach (var querySource in queryModel.BodyClauses.OfType<IQuerySource>())
{
return false;
if (QueryCompilationContext.QuerySourceMapping.ContainsMapping(querySource))
{
previousMapping.Add(
querySource,
QueryCompilationContext.QuerySourceMapping
.GetExpression(querySource));
}
}

return true;
return previousMapping;
}

private bool CanFlattenGroupJoin()
{
var groupJoinExpression = Expression as MethodCallExpression;

return groupJoinExpression != null
&& groupJoinExpression.Method.MethodIsClosedFormOf(LinqOperatorProvider.GroupJoin)
&& IsShapedQueryExpression(groupJoinExpression.Arguments[0] as MethodCallExpression, innerShapedQuery: false)
&& IsShapedQueryExpression(groupJoinExpression.Arguments[1] as MethodCallExpression, innerShapedQuery: true);
}

private class OuterJoinOrderingExtractor : ExpressionVisitor
Expand Down
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