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[rc2] SQL Server: Don't transform equality to bitwise operations in predicate contexts #36797

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[rc2] SQL Server: Don't transform equality to bitwise operations in predicate contexts #36797

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38 changes: 36 additions & 2 deletions src/EFCore.SqlServer/Query/Internal/SearchConditionConverter.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,17 @@ namespace Microsoft.EntityFrameworkCore.SqlServer.Query.Internal;
/// </remarks>
public class SearchConditionConverter(ISqlExpressionFactory sqlExpressionFactory) : ExpressionVisitor
{
/// <summary>
/// Tracks whether we're in the larger context of a predicate, even the immediate context is not a search condition.
/// </summary>
/// <remarks>
/// This visitor tracks whether the immediate context is a search condition by passing a boolean flag down during visitation,
/// and making adjustments so that the SQL is correct. However, in some cases it's useful to know whether we're in the
/// larger context of a predicate - even if the immediate context isn't a search condition; we use this to make sure the
/// SQL is efficient (as opposed to correct), refraining from transformations which could prevent index usage.
/// </remarks>
private bool _inLargerPredicateContext;

/// <summary>
/// This is an internal API that supports the Entity Framework Core infrastructure and not subject to
/// the same compatibility standards as public APIs. It may be changed or removed without notice in
Expand All @@ -42,7 +53,14 @@ public class SearchConditionConverter(ISqlExpressionFactory sqlExpressionFactory
/// </summary>
[return: NotNullIfNotNull(nameof(expression))]
protected virtual Expression? Visit(Expression? expression, bool inSearchConditionContext)
=> expression switch
{
var parentOptimizeForPredicateContext = _inLargerPredicateContext;
if (inSearchConditionContext)
{
_inLargerPredicateContext = true;
}

var result = expression switch
{
CaseExpression e => VisitCase(e, inSearchConditionContext),
SelectExpression e => VisitSelect(e),
Expand All @@ -62,6 +80,10 @@ SqlExpression e and
_ => base.Visit(expression)
};

_inLargerPredicateContext = parentOptimizeForPredicateContext;
return result;
}

private SqlExpression ApplyConversion(SqlExpression sqlExpression, bool inSearchConditionContext, bool isExpressionSearchCondition)
=> (inSearchCondition: inSearchConditionContext, isExpressionSearchCondition) switch
{
Expand Down Expand Up @@ -178,6 +200,9 @@ protected virtual Expression VisitPredicateJoin(PredicateJoinExpressionBase join
/// </summary>
protected virtual Expression VisitSelect(SelectExpression select)
{
var parentOptimizeForPredicateContext = _inLargerPredicateContext;
_inLargerPredicateContext = false;

var tables = this.VisitAndConvert(select.Tables);
var predicate = (SqlExpression?)Visit(select.Predicate, inSearchConditionContext: true);
var groupBy = this.VisitAndConvert(select.GroupBy);
Expand All @@ -187,6 +212,8 @@ protected virtual Expression VisitSelect(SelectExpression select)
var offset = (SqlExpression?)Visit(select.Offset);
var limit = (SqlExpression?)Visit(select.Limit);

_inLargerPredicateContext = parentOptimizeForPredicateContext;

return select.Update(tables, predicate, groupBy, havingExpression, projections, orderings, offset, limit);
}

Expand All @@ -208,7 +235,14 @@ protected virtual Expression VisitSqlBinary(SqlBinaryExpression binary, bool inS
{
var leftType = newLeft.TypeMapping?.Converter?.ProviderClrType ?? newLeft.Type;
var rightType = newRight.TypeMapping?.Converter?.ProviderClrType ?? newRight.Type;
if (!inSearchConditionContext

// Transform equality and inequality over bool/integer to bitwise operators:
// x != y => CAST(x ^ y AS BIT)
// x == y => CAST(~(x ^ y) AS BIT)
// However, refrain from doing this if we're within a predicate - even if the immediate context is not a search condition -
// since this might prevent index usage (e.g. we don't want this to happen within CASE THEN clauses, which aren't search
// conditions but are seen through by SQL Server when in the WHERE clause - see #36291).
if (!_inLargerPredicateContext
&& (leftType == typeof(bool) || leftType.IsInteger())
&& (rightType == typeof(bool) || rightType.IsInteger()))
{
Expand Down
7 changes: 5 additions & 2 deletions test/EFCore.SqlServer.FunctionalTests/Query/NorthwindWhereQuerySqlServerTest.cs
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Expand Up @@ -1101,9 +1101,12 @@ public override async Task Where_bool_member_and_parameter_compared_to_binary_ex
SELECT [p].[ProductID], [p].[Discontinued], [p].[ProductName], [p].[SupplierID], [p].[UnitPrice], [p].[UnitsInStock]
FROM [Products] AS [p]
WHERE [p].[Discontinued] = CASE
WHEN [p].[ProductID] > 50 THEN CAST(1 AS bit)
WHEN CASE
WHEN [p].[ProductID] > 50 THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END <> @prm THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END ^ @prm
END
""");
}

Expand Down
63 changes: 54 additions & 9 deletions test/EFCore.SqlServer.FunctionalTests/Query/NullSemanticsQuerySqlServerTest.cs
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Expand Up @@ -2466,7 +2466,13 @@ public override async Task Compare_complex_equal_equal_equal(bool async)
"""
SELECT [e].[Id]
FROM [Entities1] AS [e]
WHERE [e].[BoolA] ^ [e].[BoolB] = CAST([e].[IntA] ^ [e].[IntB] AS bit)
WHERE CASE
WHEN [e].[BoolA] = [e].[BoolB] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END = CASE
WHEN [e].[IntA] = [e].[IntB] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END
""",
//
"""
Expand Down Expand Up @@ -2502,7 +2508,13 @@ public override async Task Compare_complex_equal_not_equal_equal(bool async)
"""
SELECT [e].[Id]
FROM [Entities1] AS [e]
WHERE [e].[BoolA] ^ [e].[BoolB] <> CAST([e].[IntA] ^ [e].[IntB] AS bit)
WHERE CASE
WHEN [e].[BoolA] = [e].[BoolB] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END <> CASE
WHEN [e].[IntA] = [e].[IntB] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END
""",
//
"""
Expand Down Expand Up @@ -2538,7 +2550,13 @@ public override async Task Compare_complex_not_equal_equal_equal(bool async)
"""
SELECT [e].[Id]
FROM [Entities1] AS [e]
WHERE [e].[BoolA] ^ [e].[BoolB] = ~CAST([e].[IntA] ^ [e].[IntB] AS bit)
WHERE CASE
WHEN [e].[BoolA] <> [e].[BoolB] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END = CASE
WHEN [e].[IntA] = [e].[IntB] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END
""",
//
"""
Expand Down Expand Up @@ -2574,7 +2592,13 @@ public override async Task Compare_complex_not_equal_not_equal_equal(bool async)
"""
SELECT [e].[Id]
FROM [Entities1] AS [e]
WHERE [e].[BoolA] ^ [e].[BoolB] <> ~CAST([e].[IntA] ^ [e].[IntB] AS bit)
WHERE CASE
WHEN [e].[BoolA] <> [e].[BoolB] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END <> CASE
WHEN [e].[IntA] = [e].[IntB] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END
""",
//
"""
Expand Down Expand Up @@ -2610,7 +2634,13 @@ public override async Task Compare_complex_not_equal_equal_not_equal(bool async)
"""
SELECT [e].[Id]
FROM [Entities1] AS [e]
WHERE [e].[BoolA] ^ [e].[BoolB] = CAST([e].[IntA] ^ [e].[IntB] AS bit)
WHERE CASE
WHEN [e].[BoolA] <> [e].[BoolB] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END = CASE
WHEN [e].[IntA] <> [e].[IntB] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END
""",
//
"""
Expand Down Expand Up @@ -2646,7 +2676,13 @@ public override async Task Compare_complex_not_equal_not_equal_not_equal(bool as
"""
SELECT [e].[Id]
FROM [Entities1] AS [e]
WHERE [e].[BoolA] ^ [e].[BoolB] <> CAST([e].[IntA] ^ [e].[IntB] AS bit)
WHERE CASE
WHEN [e].[BoolA] <> [e].[BoolB] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END <> CASE
WHEN [e].[IntA] <> [e].[IntB] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END
""",
//
"""
Expand Down Expand Up @@ -4934,7 +4970,10 @@ public override async Task Comparison_compared_to_null_check_on_bool(bool async)
"""
SELECT [e].[Id], [e].[BoolA], [e].[BoolB], [e].[BoolC], [e].[IntA], [e].[IntB], [e].[IntC], [e].[NullableBoolA], [e].[NullableBoolB], [e].[NullableBoolC], [e].[NullableIntA], [e].[NullableIntB], [e].[NullableIntC], [e].[NullableStringA], [e].[NullableStringB], [e].[NullableStringC], [e].[StringA], [e].[StringB], [e].[StringC]
FROM [Entities1] AS [e]
WHERE ~CAST([e].[IntA] ^ [e].[IntB] AS bit) <> CASE
WHERE CASE
WHEN [e].[IntA] = [e].[IntB] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END <> CASE
WHEN [e].[NullableBoolA] IS NOT NULL THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END
Expand All @@ -4943,7 +4982,10 @@ ELSE CAST(0 AS bit)
"""
SELECT [e].[Id], [e].[BoolA], [e].[BoolB], [e].[BoolC], [e].[IntA], [e].[IntB], [e].[IntC], [e].[NullableBoolA], [e].[NullableBoolB], [e].[NullableBoolC], [e].[NullableIntA], [e].[NullableIntB], [e].[NullableIntC], [e].[NullableStringA], [e].[NullableStringB], [e].[NullableStringC], [e].[StringA], [e].[StringB], [e].[StringC]
FROM [Entities1] AS [e]
WHERE CAST([e].[IntA] ^ [e].[IntB] AS bit) = CASE
WHERE CASE
WHEN [e].[IntA] <> [e].[IntB] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END = CASE
WHEN [e].[NullableBoolA] IS NOT NULL THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END
Expand Down Expand Up @@ -5087,7 +5129,10 @@ public override async Task Is_null_on_column_followed_by_OrElse_optimizes_nullab
SELECT [e].[Id], [e].[BoolA], [e].[BoolB], [e].[BoolC], [e].[IntA], [e].[IntB], [e].[IntC], [e].[NullableBoolA], [e].[NullableBoolB], [e].[NullableBoolC], [e].[NullableIntA], [e].[NullableIntB], [e].[NullableIntC], [e].[NullableStringA], [e].[NullableStringB], [e].[NullableStringC], [e].[StringA], [e].[StringB], [e].[StringC]
FROM [Entities1] AS [e]
WHERE CASE
WHEN [e].[NullableBoolA] IS NULL THEN ~([e].[BoolA] ^ [e].[BoolB])
WHEN [e].[NullableBoolA] IS NULL THEN CASE
WHEN [e].[BoolA] = [e].[BoolB] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END
WHEN [e].[NullableBoolC] IS NULL THEN CASE
WHEN ([e].[NullableBoolA] <> [e].[NullableBoolC] OR [e].[NullableBoolA] IS NULL OR [e].[NullableBoolC] IS NULL) AND ([e].[NullableBoolA] IS NOT NULL OR [e].[NullableBoolC] IS NOT NULL) THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
Expand Down
5 changes: 4 additions & 1 deletion ....FunctionalTests/Query/Translations/Operators/BitwiseOperatorTranslationsSqlServerTest.cs
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Expand Up @@ -123,7 +123,10 @@ public override async Task Xor_over_boolean()
"""
SELECT [b].[Id], [b].[Bool], [b].[Byte], [b].[ByteArray], [b].[DateOnly], [b].[DateTime], [b].[DateTimeOffset], [b].[Decimal], [b].[Double], [b].[Enum], [b].[FlagsEnum], [b].[Float], [b].[Guid], [b].[Int], [b].[Long], [b].[Short], [b].[String], [b].[TimeOnly], [b].[TimeSpan]
FROM [BasicTypesEntities] AS [b]
WHERE ~CAST([b].[Int] ^ [b].[Short] AS bit) ^ CASE
WHERE CASE
WHEN [b].[Int] = [b].[Short] THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END ^ CASE
WHEN [b].[String] = N'Seattle' THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END = CAST(1 AS bit)
Expand Down
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