[WIP] Intern string metadata in Session Factory

src/NHibernate.Test/NHibernate.Test.csproj

@@ -65,6 +65,8 @@
   <ItemGroup>
     <ProjectReference Include="..\NHibernate.DomainModel\NHibernate.DomainModel.csproj" />
     <ProjectReference Include="..\NHibernate\NHibernate.csproj" />
+    <ProjectReference Include="..\RawBencher\Model\NH.Bencher.Model.csproj" />
+    <ProjectReference Include="..\RawBencher\Persistence\NH.Bencher.Persistence.csproj" />
   </ItemGroup>
   <ItemGroup>
     <Reference Include="System.Configuration" />

src/NHibernate.Test/RawBenchSessionManagerPerfomance.cs

@@ -0,0 +1,110 @@
+//#define UPSTREAM
+using System;
+using System.IO;
+using NHibernate.Util;
+using NUnit.Framework;
+
+
+namespace NHibernate.Test
+{
+	[TestFixture]
+	public class RawBenchSessionManagerPerfomance
+	{
+#if UPSTREAM
+		[Test]
+		public void InternLevel_Upstream()
+		{
+			//Just to force initialize static ctor and do not calculate memory consumed by Environoment
+			Cfg.Environment.VerifyProperties(CollectionHelper.EmptyDictionary<string, string>());
+
+			RunTest();
+		}
+
+#else
+
+		[Test]
+		public void InternLevel_Minimal()
+		{
+			Cfg.Environment.InternLevel = InternLevel.Minimal;
+			RunTest();
+		}
+
+		[Test]
+		public void InternLevel_Default()
+		{
+			Cfg.Environment.InternLevel = InternLevel.Default;
+			RunTest();
+		}
+
+		[Test]
+		public void InternLevel_SessionFactories()
+		{
+			Cfg.Environment.InternLevel = InternLevel.SessionFactories;
+			RunTest();
+		}
+
+		[Test]
+		public void InternLevel_AppDomains()
+		{
+			Cfg.Environment.InternLevel = InternLevel.AppDomains;
+			RunTest();
+		}
+
+
+#endif
+
+		private static void RunTest()
+		{
+			var factory = NH.Bencher.SessionManager.SessionFactory;
+
+			var setup = new AppDomainSetup();
+			var si = AppDomain.CurrentDomain.SetupInformation;
+			setup.ApplicationBase = si.ApplicationBase;
+			setup.ConfigurationFile = si.ConfigurationFile;
+
+			AppDomain newDomain = AppDomain.CreateDomain("New Domain", null, si);
+
+#if !UPSTREAM
+			newDomain.SetData("internLevel", Cfg.Environment.InternLevel);
+#endif
+			try
+			{
+				newDomain.DoCallBack(
+					() =>
+					{
+						StringWriter s = new StringWriter();
+						Console.SetOut(s);
+						Console.WriteLine();
+						Console.WriteLine();
+						Console.WriteLine("From new App Domain...");
+#if !UPSTREAM
+						Cfg.Environment.InternLevel = (InternLevel) AppDomain.CurrentDomain.GetData("internLevel");
+#endif
+						try
+						{
+
+							var factory2 = NH.Bencher.SessionManager.SessionFactory;
+						}
+						finally
+						{
+							AppDomain.CurrentDomain.SetData("log", s.ToString());
+							AppDomain.CurrentDomain.SetData("memory", NH.Bencher.SessionManager.LastTotalMemoryUsage);
+						}
+					});
+			}
+			finally
+			{
+				Console.WriteLine(newDomain.GetData("log"));
+				Console.WriteLine("Total Memory Usage in 2 App Domains: " + ToKbSize((long) newDomain.GetData("memory") + NH.Bencher.SessionManager.LastTotalMemoryUsage));
+
+				AppDomain.Unload(newDomain);
+			}
+		}
+
+		private static string ToKbSize(long bytes)
+		{
+			return (bytes / 1024.0).ToString("0,0.00") + " Kb";
+		}
+	}
+
+}

src/NHibernate.sln

@@ -1,6 +1,6 @@
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 15
-VisualStudioVersion = 15.0.26730.12
+VisualStudioVersion = 15.0.27130.2003
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{593DCEA7-C933-46F3-939F-D8172399AB05}"
 	ProjectSection(SolutionItems) = preProject
@@ -21,6 +21,10 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "NHibernate.TestDatabaseSetu
 EndProject
 Project("{778DAE3C-4631-46EA-AA77-85C1314464D9}") = "NHibernate.Test.VisualBasic", "NHibernate.Test.VisualBasic\NHibernate.Test.VisualBasic.vbproj", "{7C2EF610-BCA0-4D1F-898A-DE9908E4970C}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NH.Bencher.Model", "RawBencher\Model\NH.Bencher.Model.csproj", "{45DAEB56-B84D-4D7A-BF22-293F1CE07DBB}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NH.Bencher.Persistence", "RawBencher\Persistence\NH.Bencher.Persistence.csproj", "{3E9CA88C-03EC-445A-960A-242511B6EF55}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -47,6 +51,14 @@ Global
 		{7C2EF610-BCA0-4D1F-898A-DE9908E4970C}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{7C2EF610-BCA0-4D1F-898A-DE9908E4970C}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{7C2EF610-BCA0-4D1F-898A-DE9908E4970C}.Release|Any CPU.Build.0 = Release|Any CPU
+		{45DAEB56-B84D-4D7A-BF22-293F1CE07DBB}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{45DAEB56-B84D-4D7A-BF22-293F1CE07DBB}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{45DAEB56-B84D-4D7A-BF22-293F1CE07DBB}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{45DAEB56-B84D-4D7A-BF22-293F1CE07DBB}.Release|Any CPU.Build.0 = Release|Any CPU
+		{3E9CA88C-03EC-445A-960A-242511B6EF55}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{3E9CA88C-03EC-445A-960A-242511B6EF55}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{3E9CA88C-03EC-445A-960A-242511B6EF55}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{3E9CA88C-03EC-445A-960A-242511B6EF55}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

src/NHibernate/Cfg/Environment.cs

@@ -270,12 +270,15 @@ public static string Version
 		/// </summary>
 		public const string TrackSessionId = "track_session_id";
 
+		public const string StringMetadataInternLevel = "intern_level";
+
 		private static readonly Dictionary<string, string> GlobalProperties;
 
 		private static IBytecodeProvider BytecodeProviderInstance;
 		private static bool EnableReflectionOptimizer;
-
+		
 		private static readonly INHibernateLogger log = NHibernateLogger.For(typeof(Environment));
+		private static InternLevel _internLevel;
 
 		/// <summary>
 		/// Issue warnings to user when any obsolete property names are used.
@@ -299,13 +302,37 @@ static Environment()
 
 			BytecodeProviderInstance = BuildBytecodeProvider(GlobalProperties);
 			EnableReflectionOptimizer = PropertiesHelper.GetBoolean(PropertyUseReflectionOptimizer, GlobalProperties);
+
+			//TODO: Proper configuration
+			SetInternLevelFromConfig();
 
 			if (EnableReflectionOptimizer)
 			{
 				log.Info("Using reflection optimizer");
 			}
 		}
 
+		//TODO:
+		private static InternLevel SetInternLevelFromConfig()
+		{
+			return InternLevel.Default;
+			//string value = System.Configuration.ConfigurationManager.AppSettings["InternLevel"];
+			//Console.WriteLine("Path to config file: " + ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None).FilePath);
+
+			//if (string.IsNullOrEmpty(value))
+			//{
+			//	return InternLevel.Default;
+			//}
+
+			//if (!Enum.TryParse<InternLevel>(value, true, out var valueParsed))
+			//{
+			//	Console.WriteLine("Intern level setting is invalid: " + value);
+			//}
+			//Console.WriteLine("Intern level " + valueParsed);
+			//Console.WriteLine();
+			//return valueParsed;
+		}
+
 		private static void LoadGlobalPropertiesFromAppConfig()
 		{
 			object config = ConfigurationManager.GetSection(CfgXmlHelper.CfgSectionName);
@@ -388,6 +415,32 @@ public static IBytecodeProvider BytecodeProvider
 			set { BytecodeProviderInstance = value; }
 		}
 
+		/// <summary>
+		/// The bytecode provider to use.
+		/// </summary>
+		/// <remarks>
+		/// This property is read from the <c>&lt;nhibernate&gt;</c> section
+		/// of the application configuration file by default. Since it is not
+		/// always convenient to configure NHibernate through the application
+		/// configuration file, it is also possible to set the property value
+		/// manually. This should only be done before a configuration object
+		/// is created, otherwise the change may not take effect.
+		/// </remarks>
+		public static InternLevel InternLevel
+		{
+			get { return _internLevel; }
+			set
+			{
+
+				if (value !=  _internLevel)
+				{
+					Console.WriteLine("Intern level  " + value);
+				}
+				_internLevel = value; 
+
+			}
+		}
+
 		/// <summary>
 		/// Whether to enable the use of reflection optimizer
 		/// </summary>

src/NHibernate/Dialect/Lock/SelectLockingStrategy.cs

@@ -47,7 +47,7 @@ private SqlString GenerateLockString()
 			{
 				select.SetComment(lockMode + " lock " + lockable.EntityName);
 			}
-			return select.ToSqlString();
+			return select.ToSqlString(true);
 		}
 
 		#region ILockingStrategy Members
@@ -110,4 +110,4 @@ public void Lock(object id, object version, object obj, ISessionImplementor sess
 
 		#endregion
 	}
-}
+}

src/NHibernate/Loader/BasicLoader.cs

@@ -13,7 +13,7 @@ public abstract class BasicLoader : Loader
 		private IEntityAliases[] descriptors;
 		private ICollectionAliases[] collectionDescriptors;
 
-		public BasicLoader(ISessionFactoryImplementor factory) : base(factory) {}
+		public BasicLoader(ISessionFactoryImplementor factory) : base(factory) { }
 
 		protected override sealed IEntityAliases[] EntityAliases
 		{
@@ -28,14 +28,16 @@ protected override sealed ICollectionAliases[] CollectionAliases
 		protected abstract string[] Suffixes { get; }
 		protected abstract string[] CollectionSuffixes { get; }
 
+		protected virtual bool InternStringMetadata => false;
+
 		protected override void PostInstantiate()
 		{
 			ILoadable[] persisters = EntityPersisters;
 			string[] suffixes = Suffixes;
 			descriptors = new IEntityAliases[persisters.Length];
 			for (int i = 0; i < descriptors.Length; i++)
 			{
-				descriptors[i] = new DefaultEntityAliases(persisters[i], suffixes[i]);
+				descriptors[i] = new DefaultEntityAliases(persisters[i], suffixes[i], InternStringMetadata);
 			}
 
 			ICollectionPersister[] collectionPersisters = CollectionPersisters;
@@ -69,7 +71,7 @@ protected override void PostInstantiate()
 		private static bool IsBag(ICollectionPersister collectionPersister)
 		{
 			var type = collectionPersister.CollectionType.GetType();
-			return type.IsGenericType && type.GetGenericTypeDefinition() == typeof (GenericBagType<>);
+			return type.IsGenericType && type.GetGenericTypeDefinition() == typeof(GenericBagType<>);
 		}
 
 		/// <summary>

src/NHibernate/Loader/DefaultEntityAliases.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using NHibernate.Persister.Entity;
+using NHibernate.Util;
 
 namespace NHibernate.Loader
 {
@@ -34,6 +35,34 @@ public DefaultEntityAliases(IDictionary<string, string[]> userProvidedAliases, I
 			//rowIdAlias is generated on demand in property
 		}
 
+		/// <summary>
+		/// Calculate and cache select-clause aliases.
+		/// </summary>
+		public DefaultEntityAliases(ILoadable persister, string suffix, bool internAliases) : this(persister, suffix)
+		{
+			if (internAliases == false)
+				return;
+
+			const InternLevel internLevel = InternLevel.EntityAlias;
+
+			SuffixedKeyAliases = StringHelper.Intern(SuffixedKeyAliases, internLevel);
+			SuffixedPropertyAliases = InternPropertiesAliases(SuffixedPropertyAliases, internLevel);
+			SuffixedVersionAliases = StringHelper.Intern(SuffixedVersionAliases, internLevel);
+			SuffixedDiscriminatorAlias = StringHelper.Intern(SuffixedDiscriminatorAlias, internLevel);
+			if (persister.HasRowId)
+				RowIdAlias = StringHelper.Intern(RowIdAlias, internLevel);
+		}
+
+		private string[][] InternPropertiesAliases(string[][] propertiesAliases, InternLevel internLevel)
+		{
+			foreach (string[] values in propertiesAliases)
+			{
+				StringHelper.Intern(values, internLevel);
+			}
+
+			return propertiesAliases;
+		}
+
 		/// <summary>
 		/// Returns aliases for subclass persister
 		/// </summary>
@@ -63,7 +92,11 @@ public string[][] GetSuffixedPropertyAliases(ILoadable persister)
 		public string[] SuffixedKeyAliases { get; }
 
 		// TODO: not visible to the user!
-		public string RowIdAlias => _rowIdAlias ?? (_rowIdAlias = Loadable.RowIdAlias + _suffix);
+		public string RowIdAlias
+		{
+			get => _rowIdAlias ?? (_rowIdAlias = Loadable.RowIdAlias + _suffix);
+			private set => _rowIdAlias = value;
+		}
 
 		/// <summary>
 		/// Returns default aliases for all the properties
@@ -100,32 +133,32 @@ private string[] DetermineKeyAliases(ILoadable persister)
 			if (_userProvidedAliases != null)
 			{
 				var result = SafeGetUserProvidedAliases(persister.IdentifierPropertyName) ??
-				             GetUserProvidedAliases(EntityPersister.EntityID);
+							 GetUserProvidedAliases(EntityPersister.EntityID);
 
 				if (result != null)
 					return result;
 			}
 
 			return GetIdentifierAliases(persister, _suffix);
 		}
-		
+
 		private string[][] DeterminePropertyAliases(ILoadable persister)
 		{
 			return GetSuffixedPropertyAliases(persister);
 		}
-		
+
 		private string DetermineDiscriminatorAlias(ILoadable persister)
 		{
 			if (_userProvidedAliases != null)
 			{
 				var columns = GetUserProvidedAliases(AbstractEntityPersister.EntityClass);
-				if (columns != null) 
+				if (columns != null)
 					return columns[0];
 			}
 
 			return GetDiscriminatorAlias(persister, _suffix);
 		}
-		
+
 		private string[] SafeGetUserProvidedAliases(string propertyPath)
 		{
 			if (propertyPath == null)

src/NHibernate/Loader/Entity/CascadeEntityLoader.cs

@@ -16,5 +16,7 @@ public CascadeEntityLoader(IOuterJoinLoadable persister, CascadingAction action,
 
 			log.Debug("Static select for action {0} on entity {1}: {2}", action, entityName, SqlString);
 		}
+
+		protected override bool InternStringMetadata => true;
 	}
 }