Recycle various objects participating in query

dotnet · Feb 26, 2021 · 6a696a4 · 6a696a4
1 parent 416b457
commit 6a696a4
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Showing 18 changed files with 409 additions and 301 deletions.
diff --git a/src/EFCore.Relational/Query/Internal/FromSqlQueryingEnumerable.cs b/src/EFCore.Relational/Query/Internal/FromSqlQueryingEnumerable.cs
@@ -120,7 +120,10 @@ public virtual DbCommand CreateDbCommand()
         ///     doing so can result in application failures when updating to a new Entity Framework Core release.
         /// </summary>
         public virtual string ToQueryString()
-            => _relationalQueryContext.RelationalQueryStringFactory.Create(CreateDbCommand());
+        {
+            using var dbCommand = CreateDbCommand();
+            return _relationalQueryContext.RelationalQueryStringFactory.Create(dbCommand);
+        }
 
         /// <summary>
         ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
@@ -160,6 +163,7 @@ private sealed class Enumerator : IEnumerator<T>
             private readonly bool _detailedErrorsEnabled;
             private readonly IConcurrencyDetector? _concurrencyDetector;
 
+            private IRelationalCommand? _relationalCommand;
             private RelationalDataReader? _dataReader;
             private int[]? _indexMap;
 
@@ -224,9 +228,12 @@ private static bool InitializeReader(Enumerator enumerator)
             {
                 EntityFrameworkEventSource.Log.QueryExecuting();
 
-                var relationalCommand = enumerator._relationalCommandCache.GetRelationalCommand(
+                var relationalCommandTemplate = enumerator._relationalCommandCache.GetRelationalCommand(
                     enumerator._relationalQueryContext.ParameterValues);
 
+                var relationalCommand = enumerator._relationalCommand = enumerator._relationalQueryContext.Connection.RentCommand();
+                relationalCommand.PopulateFromTemplate(relationalCommandTemplate);
+
                 enumerator._dataReader = relationalCommand.ExecuteReader(
                     new RelationalCommandParameterObject(
                         enumerator._relationalQueryContext.Connection,
@@ -245,8 +252,12 @@ private static bool InitializeReader(Enumerator enumerator)
 
             public void Dispose()
             {
-                _dataReader?.Dispose();
-                _dataReader = null;
+                if (_dataReader is not null)
+                {
+                    _relationalQueryContext.Connection.ReturnCommand(_relationalCommand!);
+                    _dataReader?.Dispose();
+                    _dataReader = null;
+                }
             }
 
             public void Reset()
@@ -265,6 +276,7 @@ private sealed class AsyncEnumerator : IAsyncEnumerator<T>
             private readonly bool _detailedErrorsEnabled;
             private readonly IConcurrencyDetector? _concurrencyDetector;
 
+            private IRelationalCommand? _relationalCommand;
             private RelationalDataReader? _dataReader;
             private int[]? _indexMap;
 
@@ -331,9 +343,12 @@ private static async Task<bool> InitializeReaderAsync(AsyncEnumerator enumerator
             {
                 EntityFrameworkEventSource.Log.QueryExecuting();
 
-                var relationalCommand = enumerator._relationalCommandCache.GetRelationalCommand(
+                var relationalCommandTemplate = enumerator._relationalCommandCache.GetRelationalCommand(
                     enumerator._relationalQueryContext.ParameterValues);
 
+                var relationalCommand = enumerator._relationalCommand = enumerator._relationalQueryContext.Connection.RentCommand();
+                relationalCommand.PopulateFromTemplate(relationalCommandTemplate);
+
                 enumerator._dataReader = await relationalCommand.ExecuteReaderAsync(
                     new RelationalCommandParameterObject(
                         enumerator._relationalQueryContext.Connection,
@@ -356,6 +371,8 @@ public ValueTask DisposeAsync()
             {
                 if (_dataReader != null)
                 {
+                    _relationalQueryContext.Connection.ReturnCommand(_relationalCommand!);
+
                     var dataReader = _dataReader;
                     _dataReader = null;
 

diff --git a/src/EFCore.Relational/Query/Internal/SingleQueryingEnumerable.cs b/src/EFCore.Relational/Query/Internal/SingleQueryingEnumerable.cs
@@ -115,7 +115,10 @@ public virtual DbCommand CreateDbCommand()
         ///     doing so can result in application failures when updating to a new Entity Framework Core release.
         /// </summary>
         public virtual string ToQueryString()
-            => _relationalQueryContext.RelationalQueryStringFactory.Create(CreateDbCommand());
+        {
+            using var dbCommand = CreateDbCommand();
+            return _relationalQueryContext.RelationalQueryStringFactory.Create(dbCommand);
+        }
 
         private sealed class Enumerator : IEnumerator<T>
         {
@@ -128,6 +131,7 @@ private sealed class Enumerator : IEnumerator<T>
             private readonly bool _detailedErrorsEnabled;
             private readonly IConcurrencyDetector? _concurrencyDetector;
 
+            private IRelationalCommand? _relationalCommand;
             private RelationalDataReader? _dataReader;
             private SingleQueryResultCoordinator? _resultCoordinator;
 
@@ -218,9 +222,12 @@ private static bool InitializeReader(Enumerator enumerator)
             {
                 EntityFrameworkEventSource.Log.QueryExecuting();
 
-                var relationalCommand = enumerator._relationalCommandCache.GetRelationalCommand(
+                var relationalCommandTemplate = enumerator._relationalCommandCache.GetRelationalCommand(
                     enumerator._relationalQueryContext.ParameterValues);
 
+                var relationalCommand = enumerator._relationalCommand = enumerator._relationalQueryContext.Connection.RentCommand();
+                relationalCommand.PopulateFromTemplate(relationalCommandTemplate);
+
                 enumerator._dataReader = relationalCommand.ExecuteReader(
                     new RelationalCommandParameterObject(
                         enumerator._relationalQueryContext.Connection,
@@ -239,8 +246,12 @@ private static bool InitializeReader(Enumerator enumerator)
 
             public void Dispose()
             {
-                _dataReader?.Dispose();
-                _dataReader = null;
+                if (_dataReader is not null)
+                {
+                    _relationalQueryContext.Connection.ReturnCommand(_relationalCommand!);
+                    _dataReader.Dispose();
+                    _dataReader = null;
+                }
             }
 
             public void Reset()
@@ -258,6 +269,7 @@ private sealed class AsyncEnumerator : IAsyncEnumerator<T>
             private readonly bool _detailedErrorsEnabled;
             private readonly IConcurrencyDetector? _concurrencyDetector;
 
+            private IRelationalCommand? _relationalCommand;
             private RelationalDataReader? _dataReader;
             private SingleQueryResultCoordinator? _resultCoordinator;
 
@@ -351,9 +363,12 @@ private static async Task<bool> InitializeReaderAsync(AsyncEnumerator enumerator
             {
                 EntityFrameworkEventSource.Log.QueryExecuting();
 
-                var relationalCommand = enumerator._relationalCommandCache.GetRelationalCommand(
+                var relationalCommandTemplate = enumerator._relationalCommandCache.GetRelationalCommand(
                     enumerator._relationalQueryContext.ParameterValues);
 
+                var relationalCommand = enumerator._relationalCommand = enumerator._relationalQueryContext.Connection.RentCommand();
+                relationalCommand.PopulateFromTemplate(relationalCommandTemplate);
+
                 enumerator._dataReader = await relationalCommand.ExecuteReaderAsync(
                     new RelationalCommandParameterObject(
                         enumerator._relationalQueryContext.Connection,
@@ -374,8 +389,10 @@ private static async Task<bool> InitializeReaderAsync(AsyncEnumerator enumerator
 
             public ValueTask DisposeAsync()
             {
-                if (_dataReader != null)
+                if (_dataReader is not null)
                 {
+                    _relationalQueryContext.Connection.ReturnCommand(_relationalCommand!);
+
                     var dataReader = _dataReader;
                     _dataReader = null;
 

diff --git a/src/EFCore.Relational/Query/Internal/SplitQueryingEnumerable.cs b/src/EFCore.Relational/Query/Internal/SplitQueryingEnumerable.cs
@@ -122,7 +122,10 @@ public virtual DbCommand CreateDbCommand()
         ///     doing so can result in application failures when updating to a new Entity Framework Core release.
         /// </summary>
         public virtual string ToQueryString()
-            => $"{_relationalQueryContext.RelationalQueryStringFactory.Create(CreateDbCommand())}{Environment.NewLine}{Environment.NewLine}{RelationalStrings.SplitQueryString}";
+        {
+            using var dbCommand = CreateDbCommand();
+            return $"{_relationalQueryContext.RelationalQueryStringFactory.Create(dbCommand)}{Environment.NewLine}{Environment.NewLine}{RelationalStrings.SplitQueryString}";
+        }
 
         private sealed class Enumerator : IEnumerator<T>
         {
@@ -136,6 +139,7 @@ private sealed class Enumerator : IEnumerator<T>
             private readonly bool _detailedErrorsEnabled;
             private readonly IConcurrencyDetector? _concurrencyDetector;
 
+            private IRelationalCommand? _relationalCommand;
             private RelationalDataReader? _dataReader;
             private SplitQueryResultCoordinator? _resultCoordinator;
             private IExecutionStrategy? _executionStrategy;
@@ -212,9 +216,12 @@ private static bool InitializeReader(Enumerator enumerator)
             {
                 EntityFrameworkEventSource.Log.QueryExecuting();
 
-                var relationalCommand = enumerator._relationalCommandCache.GetRelationalCommand(
+                var relationalCommandTemplate = enumerator._relationalCommandCache.GetRelationalCommand(
                     enumerator._relationalQueryContext.ParameterValues);
 
+                var relationalCommand = enumerator._relationalCommand = enumerator._relationalQueryContext.Connection.RentCommand();
+                relationalCommand.PopulateFromTemplate(relationalCommandTemplate);
+
                 enumerator._dataReader = relationalCommand.ExecuteReader(
                     new RelationalCommandParameterObject(
                         enumerator._relationalQueryContext.Connection,
@@ -233,20 +240,24 @@ private static bool InitializeReader(Enumerator enumerator)
 
             public void Dispose()
             {
-                _dataReader?.Dispose();
-                if (_resultCoordinator != null)
+                if (_dataReader is not null)
                 {
-                    foreach (var dataReader in _resultCoordinator.DataReaders)
+                    _relationalQueryContext.Connection.ReturnCommand(_relationalCommand!);
+                    _dataReader.Dispose();
+                    if (_resultCoordinator != null)
                     {
-                        dataReader?.DataReader.Dispose();
-                    }
+                        foreach (var dataReader in _resultCoordinator.DataReaders)
+                        {
+                            dataReader?.DataReader.Dispose();
+                        }
 
-                    _resultCoordinator.DataReaders.Clear();
+                        _resultCoordinator.DataReaders.Clear();
 
-                    _resultCoordinator = null;
-                }
+                        _resultCoordinator = null;
+                    }
 
-                _dataReader = null;
+                    _dataReader = null;
+                }
             }
 
             public void Reset()
@@ -265,6 +276,7 @@ private sealed class AsyncEnumerator : IAsyncEnumerator<T>
             private readonly bool _detailedErrorEnabled;
             private readonly IConcurrencyDetector? _concurrencyDetector;
 
+            private IRelationalCommand? _relationalCommand;
             private RelationalDataReader? _dataReader;
             private SplitQueryResultCoordinator? _resultCoordinator;
             private IExecutionStrategy? _executionStrategy;
@@ -348,9 +360,12 @@ private static async Task<bool> InitializeReaderAsync(AsyncEnumerator enumerator
             {
                 EntityFrameworkEventSource.Log.QueryExecuting();
 
-                var relationalCommand = enumerator._relationalCommandCache.GetRelationalCommand(
+                var relationalCommandTemplate = enumerator._relationalCommandCache.GetRelationalCommand(
                     enumerator._relationalQueryContext.ParameterValues);
 
+                var relationalCommand = enumerator._relationalCommand = enumerator._relationalQueryContext.Connection.RentCommand();
+                relationalCommand.PopulateFromTemplate(relationalCommandTemplate);
+
                 enumerator._dataReader = await relationalCommand.ExecuteReaderAsync(
                     new RelationalCommandParameterObject(
                         enumerator._relationalQueryContext.Connection,
@@ -373,6 +388,7 @@ public async ValueTask DisposeAsync()
             {
                 if (_dataReader != null)
                 {
+                    _relationalQueryContext.Connection.ReturnCommand(_relationalCommand!);
                     await _dataReader.DisposeAsync().ConfigureAwait(false);
                     if (_resultCoordinator != null)
                     {

diff --git a/...uery/RelationalShapedQueryCompilingExpressionVisitor.ShaperProcessingExpressionVisitor.cs b/...uery/RelationalShapedQueryCompilingExpressionVisitor.ShaperProcessingExpressionVisitor.cs
@@ -1478,14 +1478,14 @@ async Task<bool> InitializeReaderAsync(DbContext _, bool result, CancellationTok
                         var relationalCommand = relationalCommandCache.GetRelationalCommand(queryContext.ParameterValues);
 
                         dataReader = await relationalCommand.ExecuteReaderAsync(
-                            new RelationalCommandParameterObject(
-                                queryContext.Connection,
-                                queryContext.ParameterValues,
-                                relationalCommandCache.ReaderColumns,
-                                queryContext.Context,
-                                queryContext.CommandLogger,
-                                detailedErrorsEnabled),
-                            cancellationToken)
+                                new RelationalCommandParameterObject(
+                                    queryContext.Connection,
+                                    queryContext.ParameterValues,
+                                    relationalCommandCache.ReaderColumns,
+                                    queryContext.Context,
+                                    queryContext.CommandLogger,
+                                    detailedErrorsEnabled),
+                                cancellationToken)
                             .ConfigureAwait(false);
 
                         return result;

diff --git a/src/EFCore.Relational/Storage/IRelationalCommand.cs b/src/EFCore.Relational/Storage/IRelationalCommand.cs
@@ -6,6 +6,7 @@
 using System.Data.Common;
 using System.Threading;
 using System.Threading.Tasks;
+using JetBrains.Annotations;
 using Microsoft.EntityFrameworkCore.Diagnostics;
 
 #nullable enable
@@ -111,5 +112,11 @@ public interface IRelationalCommand
             RelationalCommandParameterObject parameterObject,
             Guid commandId,
             DbCommandMethod commandMethod);
+
+        /// <summary>
+        ///     Populates this command from the provided <paramref name="templateCommand"/>.
+        /// </summary>
+        /// <param name="templateCommand"> A template command from which the command text and parameters will be copied. </param>
+        void PopulateFromTemplate([NotNull] IRelationalCommand templateCommand);
     }
 }
diff --git a/src/EFCore.Relational/Storage/IRelationalConnection.cs b/src/EFCore.Relational/Storage/IRelationalConnection.cs
@@ -100,6 +100,17 @@ public interface IRelationalConnection : IRelationalTransactionManager, IDisposa
         /// </returns>
         Task<bool> CloseAsync();
 
+        /// <summary>
+        ///     Rents a relational command that can be executed with this connection.
+        /// </summary>
+        /// <returns> A relational command that can be executed with this connection. </returns>
+        IRelationalCommand RentCommand();
+
+        /// <summary>
+        ///     Returns a relational command to this connection, so that it can be reused in the future.
+        /// </summary>
+        void ReturnCommand([NotNull] IRelationalCommand command);
+
         /// <summary>
         ///     Gets the current transaction.
         /// </summary>