Query: Change RelationalCommandCache to allow non-SelectExpression as…

… query expression (#28048)

Part of #795

src/EFCore.Relational/Query/Internal/FromSqlParameterExpandingExpressionVisitor.cs

@@ -26,7 +26,6 @@ private readonly IDictionary<FromSqlExpression, Expression> _visitedFromSqlExpre
     private IReadOnlyDictionary<string, object?> _parametersValues;
     private ParameterNameGenerator _parameterNameGenerator;
     private bool _canCache;
-    private SelectExpression _selectExpression;
 
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
@@ -44,7 +43,6 @@ public FromSqlParameterExpandingExpressionVisitor(
         _parameterNameGeneratorFactory = dependencies.ParameterNameGeneratorFactory;
         _parametersValues = default!;
         _parameterNameGenerator = default!;
-        _selectExpression = default!;
     }
 
     /// <summary>
@@ -58,18 +56,17 @@ public FromSqlParameterExpandingExpressionVisitor(
     ///     any release. You should only use it directly in your code with extreme caution and knowing that
     ///     doing so can result in application failures when updating to a new Entity Framework Core release.
     /// </summary>
-    public virtual SelectExpression Expand(
-        SelectExpression selectExpression,
+    public virtual Expression Expand(
+        Expression queryExpression,
         IReadOnlyDictionary<string, object?> parameterValues,
         out bool canCache)
     {
         _visitedFromSqlExpressions.Clear();
         _parameterNameGenerator = _parameterNameGeneratorFactory.Create();
         _parametersValues = parameterValues;
         _canCache = true;
-        _selectExpression = selectExpression;
 
-        var result = (SelectExpression)Visit(selectExpression);
+        var result = Visit(queryExpression);
         canCache = _canCache;
 
         return result;

src/EFCore.Relational/Query/Internal/RelationalCommandCache.cs

@@ -21,7 +21,7 @@ private static readonly ConcurrentDictionary<object, object> Locks
 
     private readonly IMemoryCache _memoryCache;
     private readonly IQuerySqlGeneratorFactory _querySqlGeneratorFactory;
-    private readonly SelectExpression _selectExpression;
+    private readonly Expression _queryExpression;
     private readonly RelationalParameterBasedSqlProcessor _relationalParameterBasedSqlProcessor;
 
     /// <summary>
@@ -34,12 +34,12 @@ public RelationalCommandCache(
         IMemoryCache memoryCache,
         IQuerySqlGeneratorFactory querySqlGeneratorFactory,
         IRelationalParameterBasedSqlProcessorFactory relationalParameterBasedSqlProcessorFactory,
-        SelectExpression selectExpression,
+        Expression queryExpression,
         bool useRelationalNulls)
     {
         _memoryCache = memoryCache;
         _querySqlGeneratorFactory = querySqlGeneratorFactory;
-        _selectExpression = selectExpression;
+        _queryExpression = queryExpression;
         _relationalParameterBasedSqlProcessor = relationalParameterBasedSqlProcessorFactory.Create(useRelationalNulls);
     }
 
@@ -51,7 +51,7 @@ public RelationalCommandCache(
     /// </summary>
     public virtual IRelationalCommandTemplate GetRelationalCommandTemplate(IReadOnlyDictionary<string, object?> parameters)
     {
-        var cacheKey = new CommandCacheKey(_selectExpression, parameters);
+        var cacheKey = new CommandCacheKey(_queryExpression, parameters);
 
         if (_memoryCache.TryGetValue(cacheKey, out IRelationalCommandTemplate? relationalCommandTemplate))
         {
@@ -69,9 +69,9 @@ public virtual IRelationalCommandTemplate GetRelationalCommandTemplate(IReadOnly
             {
                 if (!_memoryCache.TryGetValue(cacheKey, out relationalCommandTemplate))
                 {
-                    var selectExpression = _relationalParameterBasedSqlProcessor.Optimize(
-                        _selectExpression, parameters, out var canCache);
-                    relationalCommandTemplate = _querySqlGeneratorFactory.Create().GetCommand(selectExpression);
+                    var queryExpression = _relationalParameterBasedSqlProcessor.Optimize(
+                        _queryExpression, parameters, out var canCache);
+                    relationalCommandTemplate = _querySqlGeneratorFactory.Create().GetCommand(queryExpression);
 
                     if (canCache)
                     {
@@ -96,22 +96,22 @@ public virtual IRelationalCommandTemplate GetRelationalCommandTemplate(IReadOnly
     /// </summary>
     void IPrintableExpression.Print(ExpressionPrinter expressionPrinter)
     {
-        expressionPrinter.AppendLine("RelationalCommandCache.SelectExpression(");
+        expressionPrinter.AppendLine("RelationalCommandCache.QueryExpression(");
         using (expressionPrinter.Indent())
         {
-            expressionPrinter.Visit(_selectExpression);
+            expressionPrinter.Visit(_queryExpression);
             expressionPrinter.Append(")");
         }
     }
 
     private readonly struct CommandCacheKey : IEquatable<CommandCacheKey>
     {
-        private readonly SelectExpression _selectExpression;
+        private readonly Expression _queryExpression;
         private readonly IReadOnlyDictionary<string, object?> _parameterValues;
 
-        public CommandCacheKey(SelectExpression selectExpression, IReadOnlyDictionary<string, object?> parameterValues)
+        public CommandCacheKey(Expression queryExpression, IReadOnlyDictionary<string, object?> parameterValues)
         {
-            _selectExpression = selectExpression;
+            _queryExpression = queryExpression;
             _parameterValues = parameterValues;
         }
 
@@ -121,7 +121,8 @@ public override bool Equals(object? obj)
 
         public bool Equals(CommandCacheKey commandCacheKey)
         {
-            if (!ReferenceEquals(_selectExpression, commandCacheKey._selectExpression))
+            // Intentionally reference equals
+            if (!ReferenceEquals(_queryExpression, commandCacheKey._queryExpression))
             {
                 return false;
             }

src/EFCore.Relational/Query/QuerySqlGenerator.cs

@@ -61,23 +61,33 @@ public QuerySqlGenerator(QuerySqlGeneratorDependencies dependencies)
     protected virtual QuerySqlGeneratorDependencies Dependencies { get; }
 
     /// <summary>
-    ///     Gets a relational command for a <see cref="SelectExpression" />.
+    ///     Gets a relational command for a query expression.
     /// </summary>
-    /// <param name="selectExpression">A select expression to print in command text.</param>
-    /// <returns>A relational command with a SQL represented by the select expression.</returns>
-    public virtual IRelationalCommand GetCommand(SelectExpression selectExpression)
+    /// <param name="queryExpression">A query expression to print in command text.</param>
+    /// <returns>A relational command with a SQL represented by the query expression.</returns>
+    public virtual IRelationalCommand GetCommand(Expression queryExpression)
     {
         _relationalCommandBuilder = _relationalCommandBuilderFactory.Create();
 
-        GenerateTagsHeaderComment(selectExpression);
-
-        if (selectExpression.IsNonComposedFromSql())
-        {
-            GenerateFromSql((FromSqlExpression)selectExpression.Tables[0]);
-        }
-        else
+        switch (queryExpression)
         {
-            VisitSelect(selectExpression);
+            case SelectExpression selectExpression:
+            {
+                GenerateTagsHeaderComment(selectExpression);
+
+                if (selectExpression.IsNonComposedFromSql())
+                {
+                    GenerateFromSql((FromSqlExpression)selectExpression.Tables[0]);
+                }
+                else
+                {
+                    VisitSelect(selectExpression);
+                }
+            }
+            break;
+
+            default:
+                throw new InvalidOperationException();
         }
 
         return _relationalCommandBuilder.Build();

src/EFCore.Relational/Query/RelationalParameterBasedSqlProcessor.cs

@@ -8,7 +8,7 @@ namespace Microsoft.EntityFrameworkCore.Query;
 
 /// <summary>
 ///     <para>
-///         A class that processes the <see cref="SelectExpression" />  after parementer values are known.
+///         A class that processes the query expression after parementer values are known.
 ///     </para>
 ///     <para>
 ///         This type is typically used by database providers (and other extensions). It is generally
@@ -18,7 +18,7 @@ namespace Microsoft.EntityFrameworkCore.Query;
 public class RelationalParameterBasedSqlProcessor
 {
     /// <summary>
-    ///     Creates a new instance of the <see cref="QueryTranslationPostprocessor" /> class.
+    ///     Creates a new instance of the <see cref="RelationalParameterBasedSqlProcessor" /> class.
     /// </summary>
     /// <param name="dependencies">Parameter object containing dependencies for this class.</param>
     /// <param name="useRelationalNulls">A bool value indicating if relational nulls should be used.</param>
@@ -41,51 +41,51 @@ public RelationalParameterBasedSqlProcessor(
     protected virtual bool UseRelationalNulls { get; }
 
     /// <summary>
-    ///     Optimizes the <see cref="SelectExpression" /> for given parameter values.
+    ///     Optimizes the query expression for given parameter values.
     /// </summary>
-    /// <param name="selectExpression">A select expression to optimize.</param>
+    /// <param name="queryExpression">A query expression to optimize.</param>
     /// <param name="parametersValues">A dictionary of parameter values to use.</param>
-    /// <param name="canCache">A bool value indicating if the select expression can be cached.</param>
-    /// <returns>An optimized select expression.</returns>
-    public virtual SelectExpression Optimize(
-        SelectExpression selectExpression,
+    /// <param name="canCache">A bool value indicating if the query expression can be cached.</param>
+    /// <returns>An optimized query expression.</returns>
+    public virtual Expression Optimize(
+        Expression queryExpression,
         IReadOnlyDictionary<string, object?> parametersValues,
         out bool canCache)
     {
         canCache = true;
-        selectExpression = ProcessSqlNullability(selectExpression, parametersValues, out var sqlNullablityCanCache);
+        queryExpression = ProcessSqlNullability(queryExpression, parametersValues, out var sqlNullablityCanCache);
         canCache &= sqlNullablityCanCache;
 
-        selectExpression = ExpandFromSqlParameter(selectExpression, parametersValues, out var fromSqlParameterCanCache);
+        queryExpression = ExpandFromSqlParameter(queryExpression, parametersValues, out var fromSqlParameterCanCache);
         canCache &= fromSqlParameterCanCache;
 
-        return selectExpression;
+        return queryExpression;
     }
 
     /// <summary>
-    ///     Processes the <see cref="SelectExpression" /> based on nullability of nodes to apply null semantics in use and
+    ///     Processes the query expression based on nullability of nodes to apply null semantics in use and
     ///     optimize it for given parameter values.
     /// </summary>
-    /// <param name="selectExpression">A select expression to optimize.</param>
+    /// <param name="queryExpression">A query expression to optimize.</param>
     /// <param name="parametersValues">A dictionary of parameter values to use.</param>
-    /// <param name="canCache">A bool value indicating if the select expression can be cached.</param>
-    /// <returns>A processed select expression.</returns>
-    protected virtual SelectExpression ProcessSqlNullability(
-        SelectExpression selectExpression,
+    /// <param name="canCache">A bool value indicating if the query expression can be cached.</param>
+    /// <returns>A processed query expression.</returns>
+    protected virtual Expression ProcessSqlNullability(
+        Expression queryExpression,
         IReadOnlyDictionary<string, object?> parametersValues,
         out bool canCache)
-        => new SqlNullabilityProcessor(Dependencies, UseRelationalNulls).Process(selectExpression, parametersValues, out canCache);
+        => new SqlNullabilityProcessor(Dependencies, UseRelationalNulls).Process(queryExpression, parametersValues, out canCache);
 
     /// <summary>
-    ///     Expands the parameters to <see cref="FromSqlExpression" /> inside the <see cref="SelectExpression" /> for given parameter values.
+    ///     Expands the parameters to <see cref="FromSqlExpression" /> inside the query expression for given parameter values.
     /// </summary>
-    /// <param name="selectExpression">A select expression to optimize.</param>
+    /// <param name="queryExpression">A query expression to optimize.</param>
     /// <param name="parametersValues">A dictionary of parameter values to use.</param>
-    /// <param name="canCache">A bool value indicating if the select expression can be cached.</param>
-    /// <returns>A processed select expression.</returns>
-    protected virtual SelectExpression ExpandFromSqlParameter(
-        SelectExpression selectExpression,
+    /// <param name="canCache">A bool value indicating if the query expression can be cached.</param>
+    /// <returns>A processed query expression.</returns>
+    protected virtual Expression ExpandFromSqlParameter(
+        Expression queryExpression,
         IReadOnlyDictionary<string, object?> parametersValues,
         out bool canCache)
-        => new FromSqlParameterExpandingExpressionVisitor(Dependencies).Expand(selectExpression, parametersValues, out canCache);
+        => new FromSqlParameterExpandingExpressionVisitor(Dependencies).Expand(queryExpression, parametersValues, out canCache);
 }

src/EFCore.Relational/Query/SqlNullabilityProcessor.cs

@@ -59,14 +59,14 @@ public SqlNullabilityProcessor(
     protected virtual IReadOnlyDictionary<string, object?> ParameterValues { get; private set; }
 
     /// <summary>
-    ///     Processes a <see cref="SelectExpression" /> to apply null semantics and optimize it.
+    ///     Processes a query expression to apply null semantics and optimize it.
     /// </summary>
-    /// <param name="selectExpression">A select expression to process.</param>
+    /// <param name="queryExpression">A query expression to process.</param>
     /// <param name="parameterValues">A dictionary of parameter values in use.</param>
-    /// <param name="canCache">A bool value indicating whether the select expression can be cached.</param>
-    /// <returns>An optimized select expression.</returns>
-    public virtual SelectExpression Process(
-        SelectExpression selectExpression,
+    /// <param name="canCache">A bool value indicating whether the query expression can be cached.</param>
+    /// <returns>An optimized query expression.</returns>
+    public virtual Expression Process(
+        Expression queryExpression,
         IReadOnlyDictionary<string, object?> parameterValues,
         out bool canCache)
     {
@@ -75,7 +75,11 @@ public virtual SelectExpression Process(
         _nullValueColumns.Clear();
         ParameterValues = parameterValues;
 
-        var result = Visit(selectExpression);
+        var result = queryExpression switch
+        {
+            SelectExpression selectExpression => Visit(selectExpression),
+            _ => throw new InvalidOperationException()
+        };
         canCache = _canCache;
 
         return result;

src/EFCore.SqlServer/Query/Internal/SkipTakeCollapsingExpressionVisitor.cs

@@ -36,15 +36,15 @@ public SkipTakeCollapsingExpressionVisitor(ISqlExpressionFactory sqlExpressionFa
     ///     any release. You should only use it directly in your code with extreme caution and knowing that
     ///     doing so can result in application failures when updating to a new Entity Framework Core release.
     /// </summary>
-    public virtual SelectExpression Process(
-        SelectExpression selectExpression,
+    public virtual Expression Process(
+        Expression queryExpression,
         IReadOnlyDictionary<string, object?> parametersValues,
         out bool canCache)
     {
         _parameterValues = parametersValues;
         _canCache = true;
 
-        var result = (SelectExpression)Visit(selectExpression);
+        var result = Visit(queryExpression);
 
         canCache = _canCache;
 

src/EFCore.SqlServer/Query/Internal/SqlServerParameterBasedSqlProcessor.cs

@@ -32,19 +32,18 @@ public SqlServerParameterBasedSqlProcessor(
     ///     any release. You should only use it directly in your code with extreme caution and knowing that
     ///     doing so can result in application failures when updating to a new Entity Framework Core release.
     /// </summary>
-    public override SelectExpression Optimize(
-        SelectExpression selectExpression,
+    public override Expression Optimize(
+        Expression queryExpression,
         IReadOnlyDictionary<string, object?> parametersValues,
         out bool canCache)
     {
-        var optimizedSelectExpression = base.Optimize(selectExpression, parametersValues, out canCache);
+        var optimizedQueryExpression = base.Optimize(queryExpression, parametersValues, out canCache);
 
-        optimizedSelectExpression = new SkipTakeCollapsingExpressionVisitor(Dependencies.SqlExpressionFactory)
-            .Process(optimizedSelectExpression, parametersValues, out var canCache2);
+        optimizedQueryExpression = new SkipTakeCollapsingExpressionVisitor(Dependencies.SqlExpressionFactory)
+            .Process(optimizedQueryExpression, parametersValues, out var canCache2);
 
         canCache &= canCache2;
 
-        return (SelectExpression)new SearchConditionConvertingExpressionVisitor(Dependencies.SqlExpressionFactory)
-            .Visit(optimizedSelectExpression);
+        return new SearchConditionConvertingExpressionVisitor(Dependencies.SqlExpressionFactory).Visit(optimizedQueryExpression);
     }
 }