HHH-15879 Introduce a fetchable key for Fetchable within FetchableContainer

hibernate-core/src/main/java/org/hibernate/loader/ast/internal/AbstractNaturalIdLoader.java

@@ -56,6 +56,7 @@ import org.hibernate.sql.results.graph.Fetch;
 import org.hibernate.sql.results.graph.FetchParent;
 import org.hibernate.sql.results.graph.Fetchable;
 import org.hibernate.sql.results.graph.FetchableContainer;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.sql.results.spi.ListResultsConsumer;
 import org.hibernate.stat.spi.StatisticsImplementor;
 
@@ -413,12 +414,12 @@ public abstract class AbstractNaturalIdLoader<T> implements NaturalIdLoader<T> {
 		return results.get( 0 );
 	}
 
-	private static List<Fetch> visitFetches(
+	private static ImmutableFetchList visitFetches(
 			FetchParent fetchParent,
 			LoaderSqlAstCreationState creationState) {
 		final FetchableContainer fetchableContainer = fetchParent.getReferencedMappingContainer();
 		final int size = fetchableContainer.getNumberOfFetchables();
-		final List<Fetch> fetches = new ArrayList<>( size );
+		final ImmutableFetchList.Builder fetches = new ImmutableFetchList.Builder( fetchableContainer );
 		for ( int i = 0; i < size; i++ ) {
 			final Fetchable fetchable = fetchableContainer.getFetchable( i );
 			final NavigablePath navigablePath = fetchParent.resolveNavigablePath( fetchable );
@@ -432,6 +433,6 @@ public abstract class AbstractNaturalIdLoader<T> implements NaturalIdLoader<T> {
 			);
 			fetches.add( fetch );
 		}
-		return fetches;
+		return fetches.build();
 	}
 }

hibernate-core/src/main/java/org/hibernate/loader/ast/internal/DatabaseSnapshotExecutor.java

@@ -41,6 +41,7 @@ import org.hibernate.sql.exec.spi.ExecutionContext;
 import org.hibernate.sql.exec.spi.JdbcOperationQuerySelect;
 import org.hibernate.sql.exec.spi.JdbcParameterBindings;
 import org.hibernate.sql.results.graph.DomainResult;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.sql.results.internal.RowTransformerDatabaseSnapshotImpl;
 import org.hibernate.sql.results.spi.ListResultsConsumer;
 import org.hibernate.type.BasicType;
@@ -76,7 +77,7 @@ class DatabaseSnapshotExecutor {
 				sqlAliasBaseManager,
 				new FromClauseIndex( null ),
 				LockOptions.NONE,
-				(fetchParent, creationState) -> Collections.emptyList(),
+				(fetchParent, creationState) -> ImmutableFetchList.EMPTY,
 				true,
 				sessionFactory
 		);

hibernate-core/src/main/java/org/hibernate/loader/ast/internal/LoaderSelectBuilder.java

@@ -83,6 +83,7 @@ import org.hibernate.sql.results.graph.Fetchable;
 import org.hibernate.sql.results.graph.FetchableContainer;
 import org.hibernate.sql.results.graph.collection.internal.CollectionDomainResult;
 import org.hibernate.sql.results.graph.entity.EntityValuedFetchable;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.sql.results.internal.SqlSelectionImpl;
 import org.hibernate.sql.results.internal.StandardEntityGraphTraversalStateImpl;
 
@@ -648,12 +649,12 @@ public class LoaderSelectBuilder {
 		orderByFragments.add( new AbstractMap.SimpleEntry<>( orderByFragment, tableGroup ) );
 	}
 
-	private List<Fetch> visitFetches(FetchParent fetchParent, LoaderSqlAstCreationState creationState) {
+	private ImmutableFetchList visitFetches(FetchParent fetchParent, LoaderSqlAstCreationState creationState) {
 		if ( log.isTraceEnabled() ) {
 			log.tracef( "Starting visitation of FetchParent's Fetchables : %s", fetchParent.getNavigablePath() );
 		}
 
-		final List<Fetch> fetches = new ArrayList<>();
+		final ImmutableFetchList.Builder fetches = new ImmutableFetchList.Builder( fetchParent.getReferencedMappingContainer() );
 		final BiConsumer<Fetchable, Boolean> processor = createFetchableBiConsumer(
 				fetchParent,
 				creationState,
@@ -671,13 +672,13 @@ public class LoaderSelectBuilder {
 		for ( int i = 0; i < size; i++ ) {
 			processor.accept( referencedMappingContainer.getFetchable( i ), false );
 		}
-		return fetches;
+		return fetches.build();
 	}
 
 	private BiConsumer<Fetchable, Boolean> createFetchableBiConsumer(
 			FetchParent fetchParent,
 			LoaderSqlAstCreationState creationState,
-			List<Fetch> fetches) {
+			ImmutableFetchList.Builder fetches) {
 		return (fetchable, isKeyFetchable) -> {
 			final NavigablePath fetchablePath;
 

hibernate-core/src/main/java/org/hibernate/loader/ast/internal/LoaderSqlAstCreationState.java

@@ -38,6 +38,7 @@ import org.hibernate.sql.ast.tree.select.QueryPart;
 import org.hibernate.sql.results.graph.DomainResultCreationState;
 import org.hibernate.sql.results.graph.Fetch;
 import org.hibernate.sql.results.graph.FetchParent;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 
 /**
  * Helper used when generating the database-snapshot select query
@@ -45,7 +46,7 @@ import org.hibernate.sql.results.graph.FetchParent;
 public class LoaderSqlAstCreationState
 		implements SqlAstQueryPartProcessingState, SqlAstCreationState, DomainResultCreationState, QueryOptions {
 	public interface FetchProcessor {
-		List<Fetch> visitFetches(FetchParent fetchParent, LoaderSqlAstCreationState creationState);
+		ImmutableFetchList visitFetches(FetchParent fetchParent, LoaderSqlAstCreationState creationState);
 	}
 
 	private final SqlAliasBaseManager sqlAliasBaseManager;
@@ -119,15 +120,15 @@ public class LoaderSqlAstCreationState
 	}
 
 	@Override
-	public List<Fetch> visitFetches(FetchParent fetchParent) {
+	public ImmutableFetchList visitFetches(FetchParent fetchParent) {
 		return fetchProcessor.visitFetches( fetchParent, this );
 	}
 
 	@Override
-	public List<Fetch> visitNestedFetches(FetchParent fetchParent) {
+	public ImmutableFetchList visitNestedFetches(FetchParent fetchParent) {
 		final FetchParent nestingFetchParent = processingState.getNestingFetchParent();
 		processingState.setNestingFetchParent( fetchParent );
-		final List<Fetch> fetches = fetchProcessor.visitFetches( fetchParent, this );
+		final ImmutableFetchList fetches = fetchProcessor.visitFetches( fetchParent, this );
 		processingState.setNestingFetchParent( nestingFetchParent );
 		return fetches;
 	}

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/BasicEntityIdentifierMapping.java

@@ -14,4 +14,8 @@ import org.hibernate.metamodel.mapping.internal.SingleAttributeIdentifierMapping
  * @author Steve Ebersole
  */
 public interface BasicEntityIdentifierMapping extends SingleAttributeIdentifierMapping, BasicValuedModelPart {
+	@Override
+	default int getFetchableKey() {
+		return -1;
+	}
 }

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/CompositeIdentifierMapping.java

@@ -16,6 +16,11 @@ import org.hibernate.engine.spi.IdentifierValue;
  */
 public interface CompositeIdentifierMapping extends EntityIdentifierMapping, EmbeddableValuedModelPart {
 
+	@Override
+	default int getFetchableKey() {
+		return -1;
+	}
+
 	@Override
 	default IdentifierValue getUnsavedStrategy() {
 		return IdentifierValue.UNDEFINED;

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/EntityDiscriminatorMapping.java

@@ -42,6 +42,11 @@ public interface EntityDiscriminatorMapping extends VirtualModelPart, BasicValue
 		return getPartName();
 	}
 
+	@Override
+	default int getFetchableKey() {
+		return -2;
+	}
+
 	DiscriminatorType getDiscriminatorType();
 
 	String getConcreteEntityNameForDiscriminatorValue(Object value);

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/NonAggregatedIdentifierMapping.java

@@ -45,6 +45,11 @@ public interface NonAggregatedIdentifierMapping extends CompositeIdentifierMappi
 	 */
 	IdentifierValueMapper getIdentifierValueMapper();
 
+	@Override
+	default int getFetchableKey() {
+		return -1;
+	}
+
 	/**
 	 * Think of an AttributeConverter for id values to account for representation
 	 * difference between virtual and id-class mappings

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/PluralAttributeMapping.java

@@ -99,6 +99,11 @@ public interface PluralAttributeMapping
 		return 1;
 	}
 
+	@Override
+	default int getNumberOfFetchableKeys() {
+		return getNumberOfKeyFetchables() + getNumberOfFetchables();
+	}
+
 	@Override
 	default void visitFetchables(IndexedConsumer<? super Fetchable> fetchableConsumer, EntityMappingType treatTargetType) {
 		fetchableConsumer.accept( 0, getElementDescriptor() );

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/AbstractAttributeMapping.java

@@ -17,11 +17,13 @@ import org.hibernate.type.descriptor.java.JavaType;
  */
 public abstract class AbstractAttributeMapping implements AttributeMapping {
 	private final String name;
+	private final int fetchableIndex;
 
 	private final ManagedMappingType declaringType;
 
-	public AbstractAttributeMapping(String name, ManagedMappingType declaringType) {
+	public AbstractAttributeMapping(String name, int fetchableIndex, ManagedMappingType declaringType) {
 		this.name = name;
+		this.fetchableIndex = fetchableIndex;
 		this.declaringType = declaringType;
 	}
 
@@ -35,6 +37,11 @@ public abstract class AbstractAttributeMapping implements AttributeMapping {
 		return name;
 	}
 
+	@Override
+	public int getFetchableKey() {
+		return fetchableIndex;
+	}
+
 	@Override
 	public MappingType getPartMappingType() {
 		return getMappedType();

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/AbstractEmbeddableMapping.java

@@ -300,6 +300,7 @@ public abstract class AbstractEmbeddableMapping implements EmbeddableMappingType
 						bootPropertyDescriptor.getName(),
 						navigableRole.append( bootPropertyDescriptor.getName() ),
 						attributeIndex,
+						attributeIndex,
 						bootPropertyDescriptor,
 						declarer,
 						(BasicType<?>) subtype,
@@ -380,6 +381,7 @@ public abstract class AbstractEmbeddableMapping implements EmbeddableMappingType
 						typeConfiguration.getJavaTypeRegistry().getDescriptor( Object.class ),
 						declarer,
 						attributeIndex,
+						attributeIndex,
 						attributeMetadataAccess,
 						bootPropertyDescriptor.isLazy() ? FetchTiming.DELAYED : FetchTiming.IMMEDIATE,
 						propertyAccess,
@@ -407,6 +409,7 @@ public abstract class AbstractEmbeddableMapping implements EmbeddableMappingType
 				attributeMapping = MappingModelCreationHelper.buildEmbeddedAttributeMapping(
 						bootPropertyDescriptor.getName(),
 						attributeIndex,
+						attributeIndex,
 						bootPropertyDescriptor,
 						declarer,
 						subCompositeType,
@@ -426,6 +429,7 @@ public abstract class AbstractEmbeddableMapping implements EmbeddableMappingType
 				attributeMapping = MappingModelCreationHelper.buildPluralAttributeMapping(
 						bootPropertyDescriptor.getName(),
 						attributeIndex,
+						attributeIndex,
 						bootPropertyDescriptor,
 						entityPersister,
 						propertyAccess,
@@ -442,6 +446,7 @@ public abstract class AbstractEmbeddableMapping implements EmbeddableMappingType
 						bootPropertyDescriptor.getName(),
 						navigableRole.append( bootPropertyDescriptor.getName() ),
 						attributeIndex,
+						attributeIndex,
 						bootPropertyDescriptor,
 						entityPersister,
 						entityPersister,

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/AbstractEntityCollectionPart.java

@@ -114,6 +114,11 @@ public abstract class AbstractEntityCollectionPart implements EntityCollectionPa
 		return nature.getName();
 	}
 
+	@Override
+	public int getFetchableKey() {
+		return nature == Nature.INDEX || !collectionDescriptor.hasIndex() ? 0 : 1;
+	}
+
 	@Override
 	public EntityMappingType getAssociatedEntityMappingType() {
 		return associatedEntityTypeDescriptor;

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/AbstractSingularAttributeMapping.java

@@ -27,23 +27,25 @@ public abstract class AbstractSingularAttributeMapping
 	public AbstractSingularAttributeMapping(
 			String name,
 			int stateArrayPosition,
+			int fetchableIndex,
 			AttributeMetadata attributeMetadata,
 			FetchOptions mappedFetchOptions,
 			ManagedMappingType declaringType,
 			PropertyAccess propertyAccess) {
-		super( name, attributeMetadata, mappedFetchOptions, stateArrayPosition, declaringType );
+		super( name, attributeMetadata, mappedFetchOptions, stateArrayPosition, fetchableIndex, declaringType );
 		this.propertyAccess = propertyAccess;
 	}
 
 	public AbstractSingularAttributeMapping(
 			String name,
 			int stateArrayPosition,
+			int fetchableIndex,
 			AttributeMetadata attributeMetadata,
 			FetchTiming fetchTiming,
 			FetchStyle fetchStyle,
 			ManagedMappingType declaringType,
 			PropertyAccess propertyAccess) {
-		super( name, attributeMetadata, fetchTiming, fetchStyle, stateArrayPosition, declaringType );
+		super( name, attributeMetadata, fetchTiming, fetchStyle, stateArrayPosition, fetchableIndex, declaringType );
 		this.propertyAccess = propertyAccess;
 	}
 

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/AbstractStateArrayContributorMapping.java

@@ -30,8 +30,9 @@ public abstract class AbstractStateArrayContributorMapping
 			FetchTiming fetchTiming,
 			FetchStyle fetchStyle,
 			int stateArrayPosition,
+			int fetchableIndex,
 			ManagedMappingType declaringType) {
-		super( name, declaringType );
+		super( name, fetchableIndex, declaringType );
 		this.attributeMetadata = attributeMetadata;
 		this.fetchTiming = fetchTiming;
 		this.fetchStyle = fetchStyle;
@@ -43,6 +44,7 @@ public abstract class AbstractStateArrayContributorMapping
 			AttributeMetadata attributeMetadata,
 			FetchOptions mappedFetchOptions,
 			int stateArrayPosition,
+			int fetchableIndex,
 			ManagedMappingType declaringType) {
 		this(
 				name,
@@ -50,6 +52,7 @@ public abstract class AbstractStateArrayContributorMapping
 				mappedFetchOptions.getTiming(),
 				mappedFetchOptions.getStyle(),
 				stateArrayPosition,
+				fetchableIndex,
 				declaringType
 		);
 	}

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/AnyDiscriminatorPart.java

@@ -59,8 +59,8 @@ public class AnyDiscriminatorPart implements BasicValuedModelPart, FetchOptions,
 	private final Integer precision;
 	private final Integer scale;
 
-	private boolean isInsertable;
-	private boolean isUpdateable;
+	private final boolean insertable;
+	private final boolean updateable;
 	private final MetaType metaType;
 
 	public AnyDiscriminatorPart(
@@ -83,8 +83,8 @@ public class AnyDiscriminatorPart implements BasicValuedModelPart, FetchOptions,
 		this.length = length;
 		this.precision = precision;
 		this.scale = scale;
-		this.isInsertable = insertable;
-		this.isUpdateable = updateable;
+		this.insertable = insertable;
+		this.updateable = updateable;
 		this.metaType = metaType;
 	}
 
@@ -118,12 +118,12 @@ public class AnyDiscriminatorPart implements BasicValuedModelPart, FetchOptions,
 
 	@Override
 	public boolean isInsertable() {
-		return isInsertable;
+		return insertable;
 	}
 
 	@Override
 	public boolean isUpdateable() {
-		return isUpdateable;
+		return updateable;
 	}
 
 	@Override
@@ -235,6 +235,11 @@ public class AnyDiscriminatorPart implements BasicValuedModelPart, FetchOptions,
 		return getPartName();
 	}
 
+	@Override
+	public int getFetchableKey() {
+		return 0;
+	}
+
 	@Override
 	public FetchOptions getMappedFetchOptions() {
 		return this;

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/AnyKeyPart.java

@@ -54,8 +54,8 @@ public class AnyKeyPart implements BasicValuedModelPart, FetchOptions {
 	private final Integer precision;
 	private final Integer scale;
 	private final boolean nullable;
-	private boolean isInsertable;
-	private boolean isUpdateable;
+	private final boolean insertable;
+	private final boolean updateable;
 	private final JdbcMapping jdbcMapping;
 
 	public AnyKeyPart(
@@ -80,8 +80,8 @@ public class AnyKeyPart implements BasicValuedModelPart, FetchOptions {
 		this.precision = precision;
 		this.scale = scale;
 		this.nullable = nullable;
-		this.isInsertable = insertable;
-		this.isUpdateable = updateable;
+		this.insertable = insertable;
+		this.updateable = updateable;
 		this.jdbcMapping = jdbcMapping;
 	}
 
@@ -107,12 +107,12 @@ public class AnyKeyPart implements BasicValuedModelPart, FetchOptions {
 
 	@Override
 	public boolean isInsertable() {
-		return isInsertable;
+		return insertable;
 	}
 
 	@Override
 	public boolean isUpdateable() {
-		return isUpdateable;
+		return updateable;
 	}
 
 	@Override
@@ -180,6 +180,11 @@ public class AnyKeyPart implements BasicValuedModelPart, FetchOptions {
 		return getPartName();
 	}
 
+	@Override
+	public int getFetchableKey() {
+		return 1;
+	}
+
 	@Override
 	public FetchOptions getMappedFetchOptions() {
 		return this;

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/BasicAttributeMapping.java

@@ -69,6 +69,7 @@ public class BasicAttributeMapping
 			String attributeName,
 			NavigableRole navigableRole,
 			int stateArrayPosition,
+			int fetchableIndex,
 			AttributeMetadata attributeMetadata,
 			FetchTiming mappedFetchTiming,
 			FetchStyle mappedFetchStyle,
@@ -91,6 +92,7 @@ public class BasicAttributeMapping
 		super(
 				attributeName,
 				stateArrayPosition,
+				fetchableIndex,
 				attributeMetadata,
 				mappedFetchTiming,
 				mappedFetchStyle,
@@ -155,6 +157,7 @@ public class BasicAttributeMapping
 				attributeName,
 				original.getNavigableRole(),
 				stateArrayPosition,
+				original.getFetchableKey(),
 				attributeMetadata,
 				FetchTiming.IMMEDIATE,
 				FetchStyle.JOIN,

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/BasicValuedCollectionPart.java

@@ -232,6 +232,11 @@ public class BasicValuedCollectionPart
 		return nature.getName();
 	}
 
+	@Override
+	public int getFetchableKey() {
+		return nature == Nature.INDEX || !collectionDescriptor.hasIndex() ? 0 : 1;
+	}
+
 	@Override
 	public FetchOptions getMappedFetchOptions() {
 		return this;

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/CollectionIdentifierDescriptorImpl.java

@@ -206,6 +206,11 @@ public class CollectionIdentifierDescriptorImpl implements CollectionIdentifierD
 		return null;
 	}
 
+	@Override
+	public int getFetchableKey() {
+		return -1;
+	}
+
 	@Override
 	public FetchOptions getMappedFetchOptions() {
 		return this;

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/CompoundNaturalIdMapping.java

@@ -8,7 +8,6 @@ package org.hibernate.metamodel.mapping.internal;
 
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.function.BiConsumer;
@@ -19,7 +18,6 @@ import org.hibernate.NotYetImplementedFor6Exception;
 import org.hibernate.engine.spi.PersistenceContext;
 import org.hibernate.engine.spi.SessionFactoryImplementor;
 import org.hibernate.engine.spi.SharedSessionContractImplementor;
-import org.hibernate.internal.util.collections.CollectionHelper;
 import org.hibernate.loader.ast.internal.CompoundNaturalIdLoader;
 import org.hibernate.loader.ast.internal.MultiNaturalIdLoaderStandard;
 import org.hibernate.loader.ast.spi.MultiNaturalIdLoader;
@@ -48,6 +46,7 @@ import org.hibernate.sql.results.graph.FetchParentAccess;
 import org.hibernate.sql.results.graph.Fetchable;
 import org.hibernate.sql.results.graph.FetchableContainer;
 import org.hibernate.sql.results.graph.entity.EntityInitializer;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.sql.results.jdbc.spi.JdbcValuesSourceProcessingOptions;
 import org.hibernate.sql.results.jdbc.spi.RowProcessingState;
 import org.hibernate.type.descriptor.java.JavaType;
@@ -453,7 +452,9 @@ public class CompoundNaturalIdMapping extends AbstractNaturalIdMapping implement
 		private final CompoundNaturalIdMapping naturalIdMapping;
 		private final JavaType<Object[]> arrayJtd;
 
-		private final List<Fetch> fetches;
+		private final ImmutableFetchList fetches;
+		private final boolean hasJoinFetches;
+		private final boolean containsCollectionFetches;
 
 		private final String resultVariable;
 
@@ -468,7 +469,9 @@ public class CompoundNaturalIdMapping extends AbstractNaturalIdMapping implement
 			this.arrayJtd = arrayJtd;
 			this.resultVariable = resultVariable;
 
-			this.fetches = Collections.unmodifiableList( creationState.visitFetches( this ) );
+			this.fetches = creationState.visitFetches( this );
+			this.hasJoinFetches = this.fetches.hasJoinFetches();
+			this.containsCollectionFetches = this.fetches.containsCollectionFetches();
 		}
 
 		// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -517,22 +520,24 @@ public class CompoundNaturalIdMapping extends AbstractNaturalIdMapping implement
 		}
 
 		@Override
-		public List<Fetch> getFetches() {
+		public ImmutableFetchList getFetches() {
 			return fetches;
 		}
 
 		@Override
 		public Fetch findFetch(Fetchable fetchable) {
 			assert fetchable != null;
-
-			for ( int i = 0; i < fetches.size(); i++ ) {
-				final Fetch fetch = fetches.get( i );
-				if ( fetchable.equals( fetch.getFetchedMapping() ) ) {
-					return fetch;
-				}
+			return fetches.get( fetchable );
 		}
 
-			return null;
+		@Override
+		public boolean hasJoinFetches() {
+			return hasJoinFetches;
+		}
+
+		@Override
+		public boolean containsCollectionFetches() {
+			return containsCollectionFetches;
 		}
 	}
 
@@ -541,10 +546,10 @@ public class CompoundNaturalIdMapping extends AbstractNaturalIdMapping implement
 		private final CompoundNaturalIdMapping naturalIdMapping;
 		private final JavaType<Object[]> jtd;
 
-		private final List<DomainResultAssembler<?>> subAssemblers;
+		private final DomainResultAssembler<?>[] subAssemblers;
 
 		private AssemblerImpl(
-				List<Fetch> fetches,
+				ImmutableFetchList fetches,
 				NavigablePath navigablePath,
 				CompoundNaturalIdMapping naturalIdMapping,
 				JavaType<Object[]> jtd,
@@ -557,11 +562,10 @@ public class CompoundNaturalIdMapping extends AbstractNaturalIdMapping implement
 			// we just "need it" as an impl detail for handling Fetches
 			final InitializerImpl initializer = new InitializerImpl( navigablePath, naturalIdMapping );
 
-			this.subAssemblers = CollectionHelper.arrayList( fetches.size() );
-			for ( int i = 0; i < fetches.size(); i++ ) {
-				final Fetch fetch = fetches.get( i );
-				final DomainResultAssembler<?> fetchAssembler = fetch.createAssembler( initializer, creationState );
-				subAssemblers.add( fetchAssembler );
+			this.subAssemblers = new DomainResultAssembler[fetches.size()];
+			int i = 0;
+			for ( Fetch fetch : fetches ) {
+				subAssemblers[i++] = fetch.createAssembler( initializer, creationState );
 			}
 		}
 
@@ -569,9 +573,9 @@ public class CompoundNaturalIdMapping extends AbstractNaturalIdMapping implement
 		public Object[] assemble(
 				RowProcessingState rowProcessingState,
 				JdbcValuesSourceProcessingOptions options) {
-			final Object[] result = new Object[ subAssemblers.size() ];
-			for ( int i = 0; i < subAssemblers.size(); i++ ) {
-				result[ i ] = subAssemblers.get( i ).assemble( rowProcessingState, options );
+			final Object[] result = new Object[ subAssemblers.length ];
+			for ( int i = 0; i < subAssemblers.length; i++ ) {
+				result[ i ] = subAssemblers[i].assemble( rowProcessingState, options );
 			}
 			return result;
 		}

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/DiscriminatedAssociationAttributeMapping.java

@@ -71,6 +71,7 @@ public class DiscriminatedAssociationAttributeMapping
 			JavaType<?> baseAssociationJtd,
 			ManagedMappingType declaringType,
 			int stateArrayPosition,
+			int fetchableIndex,
 			AttributeMetadata attributeMetadata,
 			FetchTiming fetchTiming,
 			PropertyAccess propertyAccess,
@@ -81,6 +82,7 @@ public class DiscriminatedAssociationAttributeMapping
 		super(
 				bootProperty.getName(),
 				stateArrayPosition,
+				fetchableIndex,
 				attributeMetadata,
 				fetchTiming,
 				FetchStyle.SELECT,
@@ -188,8 +190,10 @@ public class DiscriminatedAssociationAttributeMapping
 	public Fetchable getFetchable(int position) {
 		switch ( position ) {
 			case 0:
+				assert getDiscriminatorPart().getFetchableKey() == 0;
 				return getDiscriminatorPart();
 			case 1:
+				assert getKeyPart().getFetchableKey() == 1;
 				return getKeyPart();
 		}
 		throw new IndexOutOfBoundsException(position);

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/DiscriminatedAssociationMapping.java

@@ -44,6 +44,7 @@ import org.hibernate.sql.results.graph.FetchOptions;
 import org.hibernate.sql.results.graph.FetchParent;
 import org.hibernate.sql.results.graph.FetchParentAccess;
 import org.hibernate.sql.results.graph.Fetchable;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.sql.results.jdbc.spi.JdbcValuesSourceProcessingOptions;
 import org.hibernate.sql.results.jdbc.spi.RowProcessingState;
 import org.hibernate.type.AnyType;
@@ -413,7 +414,7 @@ public class DiscriminatedAssociationMapping implements MappingType, FetchOption
 
 		private Fetch discriminatorValueFetch;
 		private Fetch keyValueFetch;
-		private List<Fetch> fetches;
+		private ImmutableFetchList fetches;
 
 		public AnyValuedResultGraphNode(
 				NavigablePath navigablePath,
@@ -425,11 +426,11 @@ public class DiscriminatedAssociationMapping implements MappingType, FetchOption
 		}
 
 		protected void afterInitialize(DomainResultCreationState creationState) {
-			this.fetches = Collections.unmodifiableList( creationState.visitFetches( this ) );
+			this.fetches = creationState.visitFetches( this );
 			assert fetches.size() == 2;
 
-			discriminatorValueFetch = fetches.get( 0 );
-			keyValueFetch = fetches.get( 1 );
+			discriminatorValueFetch = fetches.get( graphedPart.getDiscriminatorPart() );
+			keyValueFetch = fetches.get( graphedPart.getKeyPart() );
 		}
 
 		public Fetch getDiscriminatorValueFetch() {
@@ -470,7 +471,7 @@ public class DiscriminatedAssociationMapping implements MappingType, FetchOption
 		}
 
 		@Override
-		public List<Fetch> getFetches() {
+		public ImmutableFetchList getFetches() {
 			return fetches;
 		}
 
@@ -486,6 +487,16 @@ public class DiscriminatedAssociationMapping implements MappingType, FetchOption
 
 			throw new IllegalArgumentException( "Given Fetchable [" + fetchable + "] did not match either discriminator nor key mapping" );
 		}
+
+		@Override
+		public boolean hasJoinFetches() {
+			return false;
+		}
+
+		@Override
+		public boolean containsCollectionFetches() {
+			return false;
+		}
 	}
 
 	private static class AnyValuedResult<T> extends AnyValuedResultGraphNode implements DomainResult<T> {

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/DiscriminatedCollectionPart.java

@@ -117,6 +117,11 @@ public class DiscriminatedCollectionPart implements DiscriminatedAssociationMode
 		return nature.getName();
 	}
 
+	@Override
+	public int getFetchableKey() {
+		return nature == Nature.INDEX || !collectionDescriptor.hasIndex() ? 0 : 1;
+	}
+
 	@Override
 	public FetchOptions getMappedFetchOptions() {
 		return discriminatorMapping;

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/EmbeddableMappingTypeImpl.java

@@ -407,6 +407,7 @@ public class EmbeddableMappingTypeImpl extends AbstractEmbeddableMapping impleme
 						bootPropertyDescriptor.getName(),
 						valueMapping.getNavigableRole().append( bootPropertyDescriptor.getName() ),
 						attributeIndex,
+						attributeIndex,
 						bootPropertyDescriptor,
 						this,
 						(BasicType<?>) subtype,
@@ -488,6 +489,7 @@ public class EmbeddableMappingTypeImpl extends AbstractEmbeddableMapping impleme
 						typeConfiguration.getJavaTypeRegistry().getDescriptor( Object.class ),
 						this,
 						attributeIndex,
+						attributeIndex,
 						attributeMetadataAccess,
 						bootPropertyDescriptor.isLazy() ? FetchTiming.DELAYED : FetchTiming.IMMEDIATE,
 						propertyAccess,
@@ -515,6 +517,7 @@ public class EmbeddableMappingTypeImpl extends AbstractEmbeddableMapping impleme
 				attributeMapping = MappingModelCreationHelper.buildEmbeddedAttributeMapping(
 						bootPropertyDescriptor.getName(),
 						attributeIndex,
+						attributeIndex,
 						bootPropertyDescriptor,
 						this,
 						subCompositeType,
@@ -533,6 +536,7 @@ public class EmbeddableMappingTypeImpl extends AbstractEmbeddableMapping impleme
 				attributeMapping = MappingModelCreationHelper.buildPluralAttributeMapping(
 						bootPropertyDescriptor.getName(),
 						attributeIndex,
+						attributeIndex,
 						bootPropertyDescriptor,
 						entityPersister,
 						representationStrategy.resolvePropertyAccess( bootPropertyDescriptor ),
@@ -548,6 +552,7 @@ public class EmbeddableMappingTypeImpl extends AbstractEmbeddableMapping impleme
 						bootPropertyDescriptor.getName(),
 						valueMapping.getNavigableRole().append( bootPropertyDescriptor.getName() ),
 						attributeIndex,
+						attributeIndex,
 						bootPropertyDescriptor,
 						entityPersister,
 						entityPersister,

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/EmbeddedAttributeMapping.java

@@ -75,6 +75,7 @@ public class EmbeddedAttributeMapping
 			String name,
 			NavigableRole navigableRole,
 			int stateArrayPosition,
+			int fetchableIndex,
 			String tableExpression,
 			AttributeMetadata attributeMetadata,
 			String parentInjectionAttributeName,
@@ -87,6 +88,7 @@ public class EmbeddedAttributeMapping
 			name,
 			navigableRole,
 			stateArrayPosition,
+			fetchableIndex,
 			tableExpression,
 			attributeMetadata,
 			getPropertyAccess( parentInjectionAttributeName, embeddableMappingType ),
@@ -102,6 +104,7 @@ public class EmbeddedAttributeMapping
 			String name,
 			NavigableRole navigableRole,
 			int stateArrayPosition,
+			int fetchableIndex,
 			String tableExpression,
 			AttributeMetadata attributeMetadata,
 			PropertyAccess parentInjectionAttributePropertyAccess,
@@ -113,6 +116,7 @@ public class EmbeddedAttributeMapping
 		super(
 				name,
 				stateArrayPosition,
+				fetchableIndex,
 				attributeMetadata,
 				mappedFetchTiming,
 				mappedFetchStyle,
@@ -139,6 +143,7 @@ public class EmbeddedAttributeMapping
 		super(
 				inverseModelPart.getFetchableName(),
 				-1,
+				inverseModelPart.getFetchableKey(),
 				null,
 				inverseModelPart.getMappedFetchOptions(),
 				keyDeclaringType,

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/EmbeddedCollectionPart.java

@@ -140,6 +140,11 @@ public class EmbeddedCollectionPart implements CollectionPart, EmbeddableValuedF
 		return getNature().getName();
 	}
 
+	@Override
+	public int getFetchableKey() {
+		return nature == Nature.INDEX || !collectionDescriptor.hasIndex() ? 0 : 1;
+	}
+
 	@Override
 	public FetchOptions getMappedFetchOptions() {
 		return this;

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/EntityVersionMappingImpl.java

@@ -207,6 +207,11 @@ public class EntityVersionMappingImpl implements EntityVersionMapping, FetchOpti
 		return attributeName;
 	}
 
+	@Override
+	public int getFetchableKey() {
+		return getVersionAttribute().getFetchableKey();
+	}
+
 	@Override
 	public FetchOptions getMappedFetchOptions() {
 		return this;

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/IdClassEmbeddable.java

@@ -107,6 +107,7 @@ public class IdClassEmbeddable extends AbstractEmbeddableMapping implements Iden
 						.append( EntityIdentifierMapping.ROLE_LOCAL_NAME )
 						.append( NavigablePath.IDENTIFIER_MAPPER_PROPERTY ),
 				-1,
+				-1,
 				idTable,
 				attributeMetadata,
 				(PropertyAccess) null,

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/MappingModelCreationHelper.java

@@ -178,6 +178,7 @@ public class MappingModelCreationHelper {
 			String attrName,
 			NavigableRole navigableRole,
 			int stateArrayPosition,
+			int fetchableIndex,
 			Property bootProperty,
 			ManagedMappingType declaringType,
 			BasicType attrType,
@@ -223,6 +224,7 @@ public class MappingModelCreationHelper {
 				attrName,
 				navigableRole,
 				stateArrayPosition,
+				fetchableIndex,
 				attributeMetadata,
 				fetchTiming,
 				fetchStyle,
@@ -249,6 +251,7 @@ public class MappingModelCreationHelper {
 	public static EmbeddedAttributeMapping buildEmbeddedAttributeMapping(
 			String attrName,
 			int stateArrayPosition,
+			int fetchableIndex,
 			Property bootProperty,
 			ManagedMappingType declaringType,
 			CompositeType attrType,
@@ -280,6 +283,7 @@ public class MappingModelCreationHelper {
 								attrName,
 								declaringType.getNavigableRole().append( attrName ),
 								stateArrayPosition,
+								fetchableIndex,
 								tableExpression,
 								attributeMetadataAccess,
 								component.getParentProperty(),
@@ -295,6 +299,7 @@ public class MappingModelCreationHelper {
 								attrName,
 								declaringType.getNavigableRole().append( attrName ),
 								stateArrayPosition,
+								fetchableIndex,
 								tableExpression,
 								attributeMetadataAccess,
 								component.getParentProperty(),
@@ -373,6 +378,7 @@ public class MappingModelCreationHelper {
 	public static PluralAttributeMapping buildPluralAttributeMapping(
 			String attrName,
 			int stateArrayPosition,
+			int fetchableIndex,
 			Property bootProperty,
 			ManagedMappingType declaringType,
 			PropertyAccess propertyAccess,
@@ -578,6 +584,7 @@ public class MappingModelCreationHelper {
 				attributeMetadata,
 				collectionMappingType,
 				stateArrayPosition,
+				fetchableIndex,
 				elementDescriptor,
 				indexDescriptor,
 				identifierDescriptor,
@@ -1492,6 +1499,7 @@ public class MappingModelCreationHelper {
 			String attrName,
 			NavigableRole navigableRole,
 			int stateArrayPosition,
+			int fetchableIndex,
 			Property bootProperty,
 			ManagedMappingType declaringType,
 			EntityPersister declaringEntityPersister,
@@ -1546,6 +1554,7 @@ public class MappingModelCreationHelper {
 					attrName,
 					navigableRole,
 					stateArrayPosition,
+					fetchableIndex,
 					(ToOne) bootProperty.getValue(),
 					attributeMetadata,
 					fetchTiming,

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/PluralAttributeMappingImpl.java

@@ -119,6 +119,7 @@ public class PluralAttributeMappingImpl
 			AttributeMetadata attributeMetadata,
 			CollectionMappingType<?> collectionMappingType,
 			int stateArrayPosition,
+			int fetchableIndex,
 			CollectionPart elementDescriptor,
 			CollectionPart indexDescriptor,
 			CollectionIdentifierDescriptor identifierDescriptor,
@@ -127,7 +128,7 @@ public class PluralAttributeMappingImpl
 			CascadeStyle cascadeStyle,
 			ManagedMappingType declaringType,
 			CollectionPersister collectionDescriptor) {
-		super( attributeName, declaringType );
+		super( attributeName, fetchableIndex, declaringType );
 		this.propertyAccess = propertyAccess;
 		this.attributeMetadata = attributeMetadata;
 		this.collectionMappingType = collectionMappingType;

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/SimpleForeignKeyDescriptor.java

@@ -581,6 +581,11 @@ public class SimpleForeignKeyDescriptor implements ForeignKeyDescriptor, BasicVa
 		return PART_NAME;
 	}
 
+	@Override
+	public int getFetchableKey() {
+		throw new UnsupportedOperationException();
+	}
+
 	@Override
 	public FetchOptions getMappedFetchOptions() {
 		return this;

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/ToOneAttributeMapping.java

@@ -160,6 +160,7 @@ public class ToOneAttributeMapping
 			String name,
 			NavigableRole navigableRole,
 			int stateArrayPosition,
+			int fetchableIndex,
 			ToOne bootValue,
 			AttributeMetadata attributeMetadata,
 			FetchOptions mappedFetchOptions,
@@ -171,6 +172,7 @@ public class ToOneAttributeMapping
 				name,
 				navigableRole,
 				stateArrayPosition,
+				fetchableIndex,
 				bootValue,
 				attributeMetadata,
 				mappedFetchOptions.getTiming(),
@@ -186,6 +188,7 @@ public class ToOneAttributeMapping
 			String name,
 			NavigableRole navigableRole,
 			int stateArrayPosition,
+			int fetchableIndex,
 			ToOne bootValue,
 			AttributeMetadata attributeMetadata,
 			FetchTiming mappedFetchTiming,
@@ -197,6 +200,7 @@ public class ToOneAttributeMapping
 		super(
 				name,
 				stateArrayPosition,
+				fetchableIndex,
 				attributeMetadata,
 				adjustFetchTiming( mappedFetchTiming, bootValue ),
 				mappedFetchStyle,
@@ -548,6 +552,7 @@ public class ToOneAttributeMapping
 		super(
 				original.getAttributeName(),
 				original.getStateArrayPosition(),
+				original.getFetchableKey(),
 				original.getAttributeMetadata(),
 				original,
 				declaringType,

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/VirtualEmbeddedAttributeMapping.java

@@ -27,6 +27,7 @@ public class VirtualEmbeddedAttributeMapping extends EmbeddedAttributeMapping im
 			String name,
 			NavigableRole navigableRole,
 			int stateArrayPosition,
+			int fetchableIndex,
 			String tableExpression,
 			AttributeMetadata attributeMetadata,
 			String parentInjectionAttributeName,
@@ -39,6 +40,7 @@ public class VirtualEmbeddedAttributeMapping extends EmbeddedAttributeMapping im
 				name,
 				navigableRole,
 				stateArrayPosition,
+				fetchableIndex,
 				tableExpression,
 				attributeMetadata,
 				parentInjectionAttributeName,
@@ -54,6 +56,7 @@ public class VirtualEmbeddedAttributeMapping extends EmbeddedAttributeMapping im
 			String name,
 			NavigableRole navigableRole,
 			int stateArrayPosition,
+			int fetchableIndex,
 			String tableExpression,
 			AttributeMetadata attributeMetadata,
 			PropertyAccess parentInjectionAttributePropertyAccess,
@@ -66,6 +69,7 @@ public class VirtualEmbeddedAttributeMapping extends EmbeddedAttributeMapping im
 				name,
 				navigableRole,
 				stateArrayPosition,
+				fetchableIndex,
 				tableExpression,
 				attributeMetadata,
 				parentInjectionAttributePropertyAccess,

hibernate-core/src/main/java/org/hibernate/persister/collection/AbstractCollectionPersister.java

@@ -125,6 +125,7 @@ import org.hibernate.sql.model.internal.TableDeleteStandard;
 import org.hibernate.sql.model.jdbc.JdbcDeleteMutation;
 import org.hibernate.sql.model.jdbc.JdbcMutationOperation;
 import org.hibernate.sql.results.graph.DomainResult;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.sql.results.internal.SqlSelectionImpl;
 import org.hibernate.generator.Generator;
 import org.hibernate.generator.InMemoryGenerator;
@@ -934,7 +935,7 @@ public abstract class AbstractCollectionPersister
 				new SqlAliasBaseManager(),
 				new SimpleFromClauseAccessImpl(),
 				LockOptions.NONE,
-				(fetchParent, creationState) -> new ArrayList<>(),
+				(fetchParent, creationState) -> ImmutableFetchList.EMPTY,
 				true,
 				getFactory()
 		);

hibernate-core/src/main/java/org/hibernate/persister/entity/AbstractEntityPersister.java

@@ -261,6 +261,7 @@ import org.hibernate.sql.results.graph.Fetchable;
 import org.hibernate.sql.results.graph.FetchableContainer;
 import org.hibernate.sql.results.graph.embeddable.EmbeddableResultGraphNode;
 import org.hibernate.sql.results.graph.entity.internal.EntityResultImpl;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.sql.results.internal.SqlSelectionImpl;
 import org.hibernate.stat.spi.StatisticsImplementor;
 import org.hibernate.tuple.NonIdentifierAttribute;
@@ -1797,10 +1798,10 @@ public abstract class AbstractEntityPersister
 		return expression;
 	}
 
-	private List<Fetch> fetchProcessor(FetchParent fetchParent, LoaderSqlAstCreationState creationState) {
+	private ImmutableFetchList fetchProcessor(FetchParent fetchParent, LoaderSqlAstCreationState creationState) {
 		final FetchableContainer fetchableContainer = fetchParent.getReferencedMappingContainer();
 		final int size = fetchableContainer.getNumberOfFetchables();
-		final List<Fetch> fetches = new ArrayList<>( size );
+		final ImmutableFetchList.Builder fetches = new ImmutableFetchList.Builder( fetchableContainer );
 
 		for ( int i = 0; i < size; i++ ) {
 			final Fetchable fetchable = fetchableContainer.getFetchable( i );
@@ -1848,7 +1849,7 @@ public abstract class AbstractEntityPersister
 			}
 		}
 
-		return fetches;
+		return fetches.build();
 	}
 
 	private boolean isSelectable(FetchParent fetchParent, Fetchable fetchable) {
@@ -4652,6 +4653,7 @@ public abstract class AbstractEntityPersister
 
 		final NonIdentifierAttribute[] properties = currentEntityMetamodel.getProperties();
 		AttributeMappingsMap.Builder mappingsBuilder = AttributeMappingsMap.builder();
+		int fetchableIndex = getFetchableIndexOffset();
 		for ( int i = 0; i < currentEntityMetamodel.getPropertySpan(); i++ ) {
 			final NonIdentifierAttribute runtimeAttrDefinition = properties[i];
 			final Property bootProperty = bootEntityDescriptor.getProperty( runtimeAttrDefinition.getName() );
@@ -4664,6 +4666,7 @@ public abstract class AbstractEntityPersister
 								runtimeAttrDefinition,
 								bootProperty,
 								stateArrayPosition++,
+								fetchableIndex++,
 								creationProcess
 						)
 				);
@@ -4701,6 +4704,7 @@ public abstract class AbstractEntityPersister
 					}
 					final ImmutableAttributeMappingList.Builder builder = new ImmutableAttributeMappingList.Builder( attributeMappings.size() );
 					visitSubTypeAttributeMappings( attributeMapping -> builder.add( attributeMapping ) );
+					assert superMappingType != null || builder.assertFetchableIndexes();
 					staticFetchableList = builder.build();
 					return true;
 				}
@@ -4767,6 +4771,30 @@ public abstract class AbstractEntityPersister
 		}
 	}
 
+	private int getFetchableIndexOffset() {
+		if ( superMappingType != null ) {
+			final EntityMappingType rootEntityDescriptor = getRootEntityDescriptor();
+			int offset = rootEntityDescriptor.getNumberOfDeclaredAttributeMappings();
+			for ( EntityMappingType subMappingType : rootEntityDescriptor.getSubMappingTypes() ) {
+				if ( subMappingType == this ) {
+					break;
+				}
+				// Determining the number of attribute mappings unfortunately has to be done this way,
+				// because calling `subMappingType.getNumberOfDeclaredAttributeMappings()` at this point
+				// may produce wrong results because subMappingType might not have completed prepareMappingModel yet
+				final int propertySpan = subMappingType.getEntityPersister().getEntityMetamodel().getPropertySpan();
+				final int superPropertySpan = subMappingType.getSuperMappingType()
+						.getEntityPersister()
+						.getEntityMetamodel()
+						.getPropertySpan();
+				final int numberOfDeclaredAttributeMappings = propertySpan - superPropertySpan;
+				offset += numberOfDeclaredAttributeMappings;
+			}
+			return offset;
+		}
+		return 0;
+	}
+
 	private void prepareMappingModel(MappingModelCreationProcess creationProcess, PersistentClass bootEntityDescriptor) {
 		final EntityInstantiator instantiator = getRepresentationStrategy().getInstantiator();
 		final Supplier<?> templateInstanceCreator;
@@ -5206,6 +5234,7 @@ public abstract class AbstractEntityPersister
 			NonIdentifierAttribute tupleAttrDefinition,
 			Property bootProperty,
 			int stateArrayPosition,
+			int fetchableIndex,
 			MappingModelCreationProcess creationProcess) {
 		final SessionFactoryImplementor sessionFactory = creationProcess.getCreationContext().getSessionFactory();
 		final JdbcServices jdbcServices = sessionFactory.getJdbcServices();
@@ -5229,6 +5258,7 @@ public abstract class AbstractEntityPersister
 					attrName,
 					getNavigableRole().append( bootProperty.getName() ),
 					stateArrayPosition,
+					fetchableIndex,
 					bootProperty,
 					this,
 					(BasicType<?>) attrType,
@@ -5318,6 +5348,7 @@ public abstract class AbstractEntityPersister
 					attrName,
 					getNavigableRole().append( bootProperty.getName() ),
 					stateArrayPosition,
+					fetchableIndex,
 					bootProperty,
 					this,
 					(BasicType<?>) attrType,
@@ -5362,6 +5393,7 @@ public abstract class AbstractEntityPersister
 					baseAssociationJtd,
 					this,
 					stateArrayPosition,
+					fetchableIndex,
 					attributeMetadataAccess,
 					bootProperty.isLazy() ? FetchTiming.DELAYED : FetchTiming.IMMEDIATE,
 					propertyAccess,
@@ -5375,6 +5407,7 @@ public abstract class AbstractEntityPersister
 			return MappingModelCreationHelper.buildEmbeddedAttributeMapping(
 					attrName,
 					stateArrayPosition,
+					fetchableIndex,
 					bootProperty,
 					this,
 					(CompositeType) attrType,
@@ -5389,6 +5422,7 @@ public abstract class AbstractEntityPersister
 			return MappingModelCreationHelper.buildPluralAttributeMapping(
 					attrName,
 					stateArrayPosition,
+					fetchableIndex,
 					bootProperty,
 					this,
 					propertyAccess,
@@ -5402,6 +5436,7 @@ public abstract class AbstractEntityPersister
 					attrName,
 					getNavigableRole().append( attrName ),
 					stateArrayPosition,
+					fetchableIndex,
 					bootProperty,
 					this,
 					this,
@@ -5659,6 +5694,11 @@ public abstract class AbstractEntityPersister
 		return getStaticFetchableList().size();
 	}
 
+	@Override
+	public int getNumberOfFetchableKeys() {
+		return superMappingType == null ? getNumberOfFetchables() : getRootEntityDescriptor().getNumberOfFetchables();
+	}
+
 	@Override
 	public int getNumberOfKeyFetchables() {
 		return 0;

hibernate-core/src/main/java/org/hibernate/persister/internal/ImmutableAttributeMappingList.java

@@ -90,6 +90,13 @@ public final class ImmutableAttributeMappingList implements AttributeMappingsLis
 			return new ImmutableAttributeMappingList( builderList );
 		}
 
+		public boolean assertFetchableIndexes() {
+			for ( int i = 0; i < builderList.size(); i++ ) {
+				final AttributeMapping attributeMapping = builderList.get( i );
+				assert i == attributeMapping.getFetchableKey();
+			}
+			return true;
+		}
 	}
 
 }

hibernate-core/src/main/java/org/hibernate/query/derived/AnonymousTupleBasicEntityIdentifierMapping.java

@@ -29,7 +29,7 @@ public class AnonymousTupleBasicEntityIdentifierMapping
 			SqmExpressible<?> expressible,
 			JdbcMapping jdbcMapping,
 			BasicEntityIdentifierMapping delegate) {
-		super( delegate.getAttributeName(), selectionExpression, expressible, jdbcMapping );
+		super( delegate.getAttributeName(), selectionExpression, expressible, jdbcMapping, -1 );
 		this.delegate = delegate;
 	}
 

hibernate-core/src/main/java/org/hibernate/query/derived/AnonymousTupleBasicValuedModelPart.java

@@ -47,16 +47,19 @@ public class AnonymousTupleBasicValuedModelPart implements ModelPart, MappingTyp
 	private final String selectionExpression;
 	private final SqmExpressible<?> expressible;
 	private final JdbcMapping jdbcMapping;
+	private final int fetchableIndex;
 
 	public AnonymousTupleBasicValuedModelPart(
 			String partName,
 			String selectionExpression,
 			SqmExpressible<?> expressible,
-			JdbcMapping jdbcMapping) {
+			JdbcMapping jdbcMapping,
+			int fetchableIndex) {
 		this.partName = partName;
 		this.selectionExpression = selectionExpression;
 		this.expressible = expressible;
 		this.jdbcMapping = jdbcMapping;
+		this.fetchableIndex = fetchableIndex;
 	}
 
 	@Override
@@ -164,6 +167,11 @@ public class AnonymousTupleBasicValuedModelPart implements ModelPart, MappingTyp
 		return partName;
 	}
 
+	@Override
+	public int getFetchableKey() {
+		return fetchableIndex;
+	}
+
 	@Override
 	public FetchOptions getMappedFetchOptions() {
 		return FETCH_OPTIONS;

hibernate-core/src/main/java/org/hibernate/query/derived/AnonymousTupleEmbeddableValuedModelPart.java

@@ -73,16 +73,19 @@ public class AnonymousTupleEmbeddableValuedModelPart implements EmbeddableValued
 	private final DomainType<?> domainType;
 	private final String componentName;
 	private final EmbeddableValuedModelPart existingModelPartContainer;
+	private final int fetchableIndex;
 
 	public AnonymousTupleEmbeddableValuedModelPart(
 			Map<String, ModelPart> modelParts,
 			DomainType<?> domainType,
 			String componentName,
-			EmbeddableValuedModelPart existingModelPartContainer) {
+			EmbeddableValuedModelPart existingModelPartContainer,
+			int fetchableIndex) {
 		this.modelParts = modelParts;
 		this.domainType = domainType;
 		this.componentName = componentName;
 		this.existingModelPartContainer = existingModelPartContainer;
+		this.fetchableIndex = fetchableIndex;
 	}
 
 	@Override
@@ -321,6 +324,11 @@ public class AnonymousTupleEmbeddableValuedModelPart implements EmbeddableValued
 		return getPartName();
 	}
 
+	@Override
+	public int getFetchableKey() {
+		return fetchableIndex;
+	}
+
 	@Override
 	public FetchOptions getMappedFetchOptions() {
 		return FETCH_OPTIONS;

hibernate-core/src/main/java/org/hibernate/query/derived/AnonymousTupleEmbeddedEntityIdentifierMapping.java

@@ -37,7 +37,8 @@ public class AnonymousTupleEmbeddedEntityIdentifierMapping extends AnonymousTupl
 				modelParts,
 				domainType,
 				componentName,
-				(EmbeddableValuedModelPart) delegate
+				(EmbeddableValuedModelPart) delegate,
+				-1
 		);
 		this.delegate = delegate;
 	}

hibernate-core/src/main/java/org/hibernate/query/derived/AnonymousTupleEntityValuedModelPart.java

@@ -82,12 +82,14 @@ public class AnonymousTupleEntityValuedModelPart
 	private final String componentName;
 	private final EntityValuedModelPart delegate;
 	private final Set<String> targetKeyPropertyNames;
+	private final int fetchableIndex;
 
 	public AnonymousTupleEntityValuedModelPart(
 			EntityIdentifierMapping identifierMapping,
 			DomainType<?> domainType,
 			String componentName,
-			EntityValuedModelPart delegate) {
+			EntityValuedModelPart delegate,
+			int fetchableIndex) {
 		this.identifierMapping = identifierMapping;
 		this.domainType = domainType;
 		this.componentName = componentName;
@@ -103,6 +105,7 @@ public class AnonymousTupleEntityValuedModelPart
 				persister.getFactory()
 		);
 		this.targetKeyPropertyNames = targetKeyPropertyNames;
+		this.fetchableIndex = fetchableIndex;
 	}
 
 	public ModelPart getForeignKeyPart() {

hibernate-core/src/main/java/org/hibernate/query/derived/AnonymousTupleNonAggregatedEntityIdentifierMapping.java

@@ -38,7 +38,8 @@ public class AnonymousTupleNonAggregatedEntityIdentifierMapping extends Anonymou
 				modelParts,
 				domainType,
 				componentName,
-				delegate
+				delegate,
+				-1
 		);
 		this.delegate = delegate;
 	}

hibernate-core/src/main/java/org/hibernate/query/derived/AnonymousTupleTableGroupProducer.java

@@ -98,7 +98,8 @@ public class AnonymousTupleTableGroupProducer implements TableGroupProducer, Map
 						partName,
 						partName,
 						tableGroup == null ? null : getModelPart( tableGroup ),
-						compatibleTableExpressions
+						compatibleTableExpressions,
+						modelParts.size()
 				);
 			}
 			else {
@@ -108,7 +109,8 @@ public class AnonymousTupleTableGroupProducer implements TableGroupProducer, Map
 						selectableNode.getExpressible(),
 						sqlSelection.getExpressionType()
 								.getJdbcMappings()
-								.get( 0 )
+								.get( 0 ),
+						modelParts.size()
 				);
 			}
 			modelParts.put( partName, modelPart );
@@ -136,7 +138,8 @@ public class AnonymousTupleTableGroupProducer implements TableGroupProducer, Map
 			String selectionExpression,
 			String partName,
 			ModelPart existingModelPart,
-			Set<String> compatibleTableExpressions) {
+			Set<String> compatibleTableExpressions,
+			int fetchableIndex) {
 		if ( domainType instanceof EntityDomainType<?> ) {
 			final EntityValuedModelPart existingModelPartContainer = (EntityValuedModelPart) existingModelPart;
 			final EntityIdentifierMapping identifierMapping = existingModelPartContainer.getEntityMappingType()
@@ -149,6 +152,7 @@ public class AnonymousTupleTableGroupProducer implements TableGroupProducer, Map
 					final Set<Attribute<?, ?>> attributes = (Set<Attribute<?, ?>>) ( (ManagedDomainType<?>) ( (EntityDomainType<?>) domainType ).getIdentifierDescriptor().getSqmPathType() ).getAttributes();
 					final Map<String, ModelPart> modelParts = CollectionHelper.linkedMapOfSize( attributes.size() );
 					final EmbeddableValuedModelPart modelPartContainer = (EmbeddableValuedModelPart) identifierMapping;
+					int index = 0;
 					for ( Attribute<?, ?> attribute : attributes ) {
 						if ( !( attribute instanceof SingularPersistentAttribute<?, ?> ) ) {
 							throw new IllegalArgumentException( "Only embeddables without collections are supported!" );
@@ -162,7 +166,8 @@ public class AnonymousTupleTableGroupProducer implements TableGroupProducer, Map
 								selectionExpression + "_" + attributeName + "_" + attribute.getName(),
 								attribute.getName(),
 								modelPartContainer.findSubPart( attribute.getName(), null ),
-								compatibleTableExpressions
+								compatibleTableExpressions,
+								index++
 						);
 						modelParts.put( modelPart.getPartName(), modelPart );
 					}
@@ -190,6 +195,7 @@ public class AnonymousTupleTableGroupProducer implements TableGroupProducer, Map
 				final Set<Attribute<?, ?>> attributes = (Set<Attribute<?, ?>>) ( (ManagedDomainType<?>) ( (EntityDomainType<?>) domainType ).getIdentifierDescriptor().getSqmPathType() ).getAttributes();
 				final Map<String, ModelPart> modelParts = CollectionHelper.linkedMapOfSize( attributes.size() );
 				final EmbeddableValuedModelPart modelPartContainer = (EmbeddableValuedModelPart) identifierMapping;
+				int index = 0;
 				for ( Attribute<?, ?> attribute : attributes ) {
 					if ( !( attribute instanceof SingularPersistentAttribute<?, ?> ) ) {
 						throw new IllegalArgumentException( "Only embeddables without collections are supported!" );
@@ -203,7 +209,8 @@ public class AnonymousTupleTableGroupProducer implements TableGroupProducer, Map
 							selectionExpression + "_" + attribute.getName(),
 							attribute.getName(),
 							modelPartContainer.findSubPart( attribute.getName(), null ),
-							compatibleTableExpressions
+							compatibleTableExpressions,
+							index++
 					);
 					modelParts.put( modelPart.getPartName(), modelPart );
 				}
@@ -222,7 +229,8 @@ public class AnonymousTupleTableGroupProducer implements TableGroupProducer, Map
 					newIdentifierMapping,
 					domainType,
 					selectionExpression,
-					existingModelPartContainer
+					existingModelPartContainer,
+					fetchableIndex
 			);
 		}
 		else if ( domainType instanceof ManagedDomainType<?> ) {
@@ -230,6 +238,7 @@ public class AnonymousTupleTableGroupProducer implements TableGroupProducer, Map
 			final Set<Attribute<?, ?>> attributes = (Set<Attribute<?, ?>>) ( (ManagedDomainType<?>) domainType ).getAttributes();
 			final Map<String, ModelPart> modelParts = CollectionHelper.linkedMapOfSize( attributes.size() );
 			final EmbeddableValuedModelPart modelPartContainer = (EmbeddableValuedModelPart) existingModelPart;
+			int index = 0;
 			for ( Attribute<?, ?> attribute : attributes ) {
 				if ( !( attribute instanceof SingularPersistentAttribute<?, ?> ) ) {
 					throw new IllegalArgumentException( "Only embeddables without collections are supported" );
@@ -243,11 +252,12 @@ public class AnonymousTupleTableGroupProducer implements TableGroupProducer, Map
 						selectionExpression + "_" + attribute.getName(),
 						attribute.getName(),
 						modelPartContainer.findSubPart( attribute.getName(), null ),
-						compatibleTableExpressions
+						compatibleTableExpressions,
+						index++
 				);
 				modelParts.put( modelPart.getPartName(), modelPart );
 			}
-			return new AnonymousTupleEmbeddableValuedModelPart( modelParts, domainType, selectionExpression, modelPartContainer );
+			return new AnonymousTupleEmbeddableValuedModelPart( modelParts, domainType, selectionExpression, modelPartContainer, fetchableIndex );
 		}
 		else {
 			return new AnonymousTupleBasicValuedModelPart(
@@ -257,7 +267,8 @@ public class AnonymousTupleTableGroupProducer implements TableGroupProducer, Map
 					sqlSelections.get( selectionIndex )
 							.getExpressionType()
 							.getJdbcMappings()
-							.get( 0 )
+							.get( 0 ),
+					fetchableIndex
 			);
 		}
 	}

hibernate-core/src/main/java/org/hibernate/query/derived/CteTupleTableGroupProducer.java

@@ -59,7 +59,8 @@ public class CteTupleTableGroupProducer extends AnonymousTupleTableGroupProducer
 					attributeName,
 					attributeName,
 					basicType,
-					basicType
+					basicType,
+					-1
 			);
 		}
 		return null;

hibernate-core/src/main/java/org/hibernate/query/results/DomainResultCreationStateImpl.java

@@ -8,7 +8,6 @@ package org.hibernate.query.results;
 
 import java.util.AbstractMap;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.function.Consumer;
 import java.util.function.Function;
@@ -17,7 +16,6 @@ import org.hibernate.Internal;
 import org.hibernate.LockMode;
 import org.hibernate.engine.FetchTiming;
 import org.hibernate.engine.spi.SessionFactoryImplementor;
-import org.hibernate.internal.util.collections.CollectionHelper;
 import org.hibernate.internal.util.collections.Stack;
 import org.hibernate.internal.util.collections.StandardStack;
 import org.hibernate.metamodel.mapping.Association;
@@ -51,6 +49,8 @@ import org.hibernate.sql.results.graph.Fetch;
 import org.hibernate.sql.results.graph.FetchParent;
 import org.hibernate.sql.results.graph.Fetchable;
 import org.hibernate.sql.results.graph.FetchableContainer;
+import org.hibernate.sql.results.graph.entity.EntityResultGraphNode;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.sql.results.jdbc.spi.JdbcValuesMetadata;
 import org.hibernate.type.descriptor.java.JavaType;
 import org.hibernate.type.spi.TypeConfiguration;
@@ -126,9 +126,8 @@ public class DomainResultCreationStateImpl
 		return jdbcResultsMetadata;
 	}
 
-	public NavigablePath getCurrentRelativePath() {
-		final Map.Entry<String, NavigablePath> entry = relativePathStack.getCurrent();
-		return entry == null ? null : entry.getValue();
+	public Map.Entry<String, NavigablePath> getCurrentRelativePath() {
+		return relativePathStack.getCurrent();
 	}
 
 	public void pushExplicitFetchMementoResolver(Function<String, FetchBuilder> resolver) {
@@ -332,26 +331,106 @@ public class DomainResultCreationStateImpl
 	}
 
 	@Override
-	public List<Fetch> visitNestedFetches(FetchParent fetchParent) {
+	public ImmutableFetchList visitNestedFetches(FetchParent fetchParent) {
 		final FetchParent oldNestingFetchParent = this.nestingFetchParent;
 		this.nestingFetchParent = fetchParent;
-		final List<Fetch> fetches = visitFetches( fetchParent );
+		final ImmutableFetchList fetches = visitFetches( fetchParent );
 		this.nestingFetchParent = oldNestingFetchParent;
 		return fetches;
 	}
 
 	@Override
-	public List<Fetch> visitFetches(FetchParent fetchParent) {
+	public Fetch visitIdentifierFetch(EntityResultGraphNode fetchParent) {
+		final EntityValuedModelPart entityValuedFetchable = fetchParent.getEntityValuedModelPart();
+		final EntityIdentifierMapping identifierMapping = entityValuedFetchable.getEntityMappingType().getIdentifierMapping();
+		final String identifierAttributeName = attributeName( identifierMapping );
+		final Map.Entry<String, NavigablePath> oldEntry = relativePathStack.getCurrent();
+		final String fullPath;
+		if ( identifierMapping instanceof NonAggregatedIdentifierMapping ) {
+			fullPath = oldEntry == null ? "" : oldEntry.getKey();
+		}
+		else {
+			fullPath = oldEntry == null ?
+					identifierAttributeName :
+					oldEntry.getKey() + "." + identifierAttributeName;
+		}
+
+		final Fetchable fetchable = (Fetchable) identifierMapping;
+		final FetchBuilder explicitFetchBuilder = fetchBuilderResolverStack
+				.getCurrent()
+				.apply( fullPath );
+		DynamicFetchBuilderLegacy fetchBuilderLegacy;
+		if ( explicitFetchBuilder == null ) {
+			fetchBuilderLegacy = legacyFetchResolver.resolve(
+					fromClauseAccess.findTableGroup( fetchParent.getNavigablePath() )
+							.getPrimaryTableReference()
+							.getIdentificationVariable(),
+					identifierAttributeName
+			);
+		}
+		else {
+			fetchBuilderLegacy = null;
+		}
+
+		final EntityIdentifierNavigablePath fetchPath = new EntityIdentifierNavigablePath(
+				fetchParent.getNavigablePath(),
+				identifierAttributeName
+		);
+
+		final boolean processingKeyFetches = this.processingKeyFetches;
+		this.processingKeyFetches = true;
+		if ( identifierMapping instanceof CompositeIdentifierMapping ) {
+			relativePathStack.push( new AbstractMap.SimpleEntry<>( fullPath, fetchPath ) );
+		}
+
+		try {
+			final FetchBuilder fetchBuilder;
+			if ( explicitFetchBuilder != null ) {
+				fetchBuilder = explicitFetchBuilder;
+			}
+			else {
+				if ( fetchBuilderLegacy == null ) {
+					fetchBuilder = Builders.implicitFetchBuilder( fetchPath, fetchable, this );
+				}
+				else {
+					fetchBuilder = fetchBuilderLegacy;
+				}
+			}
+			return fetchBuilder.buildFetch(
+					fetchParent,
+					fetchPath,
+					jdbcResultsMetadata,
+					(s, s2) -> {
+						throw new UnsupportedOperationException();
+					},
+					this
+			);
+		}
+		finally {
+			this.processingKeyFetches = processingKeyFetches;
+			if ( identifierMapping instanceof CompositeIdentifierMapping ) {
+				this.relativePathStack.pop();
+			}
+		}
+	}
+
+	@Override
+	public ImmutableFetchList visitFetches(FetchParent fetchParent) {
 		final FetchableContainer fetchableContainer = fetchParent.getReferencedMappingContainer();
+		final ImmutableFetchList.Builder fetches = new ImmutableFetchList.Builder( fetchableContainer );
+		final Consumer<Fetchable> fetchableConsumer = createFetchableConsumer( fetchParent, fetches );
+		fetchableContainer.visitKeyFetchables( fetchableConsumer, null );
+		fetchableContainer.visitFetchables( fetchableConsumer, null );
+		return fetches.build();
+	}
 
-		final List<Fetch> fetches = CollectionHelper.arrayList( fetchableContainer.getNumberOfFetchables() );
-
-		final Consumer<Fetchable> fetchableConsumer = fetchable -> {
+	private Consumer<Fetchable> createFetchableConsumer(FetchParent fetchParent, ImmutableFetchList.Builder fetches) {
+		return fetchable -> {
 			final String fetchableName = fetchable.getFetchableName();
 			Map.Entry<String, NavigablePath> currentEntry;
 			if ( relativePathStack.isEmpty() ) {
 				currentEntry = new AbstractMap.SimpleEntry<>(
-						getRelativePath( "", fetchable, fetchableContainer ),
+						getRelativePath( "", fetchable ),
 						new NavigablePath( fetchableName )
 				);
 			}
@@ -359,7 +438,7 @@ public class DomainResultCreationStateImpl
 				final Map.Entry<String, NavigablePath> oldEntry = relativePathStack.getCurrent();
 				final String key = oldEntry.getKey();
 				currentEntry = new AbstractMap.SimpleEntry<>(
-						getRelativePath( key, fetchable, fetchableContainer ),
+						getRelativePath( key, fetchable ),
 						oldEntry.getValue().append( fetchableName )
 				);
 			}
@@ -384,8 +463,9 @@ public class DomainResultCreationStateImpl
 				final Association association = (Association) fetchable;
 				final ForeignKeyDescriptor foreignKeyDescriptor = association.getForeignKeyDescriptor();
 
-				final String partName = attributeName( foreignKeyDescriptor.getSide( association.getSideNature().inverse() )
-						.getModelPart());
+				final String partName = attributeName(
+						foreignKeyDescriptor.getSide( association.getSideNature().inverse() ).getModelPart()
+				);
 
 				// If there are no fetch builders for this association, we only want to fetch the FK
 				if ( explicitFetchBuilder == null && fetchBuilderLegacy == null && partName != null ) {
@@ -438,65 +518,9 @@ public class DomainResultCreationStateImpl
 			}
 
 		};
-
-		boolean previous = this.processingKeyFetches;
-		this.processingKeyFetches = true;
-
-		if ( fetchableContainer instanceof EntityValuedModelPart ) {
-			final EntityValuedModelPart entityValuedFetchable = (EntityValuedModelPart) fetchableContainer;
-			final EntityIdentifierMapping identifierMapping = entityValuedFetchable.getEntityMappingType().getIdentifierMapping();
-			final boolean idClass = identifierMapping instanceof NonAggregatedIdentifierMapping;
-			final String identifierAttributeName = attributeName( identifierMapping );
-			if ( idClass ) {
-				final Map.Entry<String, NavigablePath> oldEntry = relativePathStack.getCurrent();
-				relativePathStack.push(
-						new AbstractMap.SimpleEntry<>(
-								oldEntry == null ? "" : oldEntry.getKey(),
-								new EntityIdentifierNavigablePath(
-										oldEntry == null ? fetchParent.getNavigablePath() : oldEntry.getValue(),
-										identifierAttributeName
-								)
-						)
-				);
-			}
-			else if ( identifierMapping instanceof CompositeIdentifierMapping ) {
-				final Map.Entry<String, NavigablePath> oldEntry = relativePathStack.getCurrent();
-				relativePathStack.push(
-						new AbstractMap.SimpleEntry<>(
-								oldEntry == null ?
-										identifierAttributeName :
-										oldEntry.getKey() + "." + identifierAttributeName,
-								new EntityIdentifierNavigablePath(
-										oldEntry == null ? fetchParent.getNavigablePath() : oldEntry.getValue(),
-										identifierAttributeName
-								)
-						)
-				);
 	}
 
-			try {
-				if ( identifierMapping instanceof FetchableContainer ) {
-					// essentially means the entity has a composite id - ask the embeddable to visit its fetchables
-					( (FetchableContainer) identifierMapping ).visitFetchables( fetchableConsumer, null );
-				}
-				else {
-					fetchableConsumer.accept( (Fetchable) identifierMapping );
-				}
-			}
-			finally {
-				this.processingKeyFetches = previous;
-				if ( idClass ) {
-					this.relativePathStack.pop();
-				}
-			}
-		}
-
-		fetchableContainer.visitKeyFetchables( fetchableConsumer, null );
-		fetchableContainer.visitFetchables( fetchableConsumer, null );
-		return fetches;
-	}
-
-	private String getRelativePath(String oldEntry, Fetchable fetchable, FetchableContainer fetchableContainer) {
+	private String getRelativePath(String oldEntry, Fetchable fetchable) {
 		if ( fetchable instanceof AttributeMapping || fetchable instanceof SingleAttributeIdentifierMapping || fetchable instanceof BasicValuedCollectionPart ) {
 			if ( !oldEntry.equals( "" ) ) {
 				return oldEntry + '.' + fetchable.getFetchableName();

hibernate-core/src/main/java/org/hibernate/query/results/ResultSetMappingImpl.java

@@ -36,6 +36,7 @@ import org.hibernate.sql.results.graph.basic.BasicFetch;
 import org.hibernate.sql.results.graph.basic.BasicResult;
 import org.hibernate.sql.results.graph.embeddable.EmbeddableResultGraphNode;
 import org.hibernate.sql.results.graph.entity.EntityResult;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.sql.results.jdbc.spi.JdbcValuesMapping;
 import org.hibernate.sql.results.jdbc.spi.JdbcValuesMappingProducer;
 import org.hibernate.sql.results.jdbc.spi.JdbcValuesMetadata;
@@ -248,7 +249,7 @@ public class ResultSetMappingImpl implements ResultSetMapping {
 				// otherwise we assume that even if there are duplicate aliases, the values are equivalent.
 				// If we don't do that, there is no way to fetch joined inheritance entities
 				if ( polymorphic && ( legacyFetchBuilders == null || legacyFetchBuilders.isEmpty() )
-						&& !hasJoinFetches( entityResult.getFetches() ) ) {
+						&& !entityResult.hasJoinFetches() ) {
 					final Set<String> aliases = new TreeSet<>( String.CASE_INSENSITIVE_ORDER );
 					final AbstractEntityPersister entityPersister = (AbstractEntityPersister) entityResult.getReferencedMappingContainer()
 							.getEntityPersister();
@@ -305,25 +306,6 @@ public class ResultSetMappingImpl implements ResultSetMapping {
 		}
 	}
 
-	private static boolean hasJoinFetches(List<Fetch> fetches) {
-		for ( int i = 0; i < fetches.size(); i++ ) {
-			final Fetch fetch = fetches.get( i );
-			if ( fetch instanceof BasicFetch<?> || fetch.getTiming() == FetchTiming.DELAYED ) {
-				// That's fine
-			}
-			else if ( fetch instanceof EmbeddableResultGraphNode ) {
-				// Check all these fetches as well
-				if ( hasJoinFetches( ( (EmbeddableResultGraphNode) fetch ).getFetches() ) ) {
-					return true;
-				}
-			}
-			else {
-				return true;
-			}
-		}
-		return false;
-	}
-
 	private DomainResult<?> makeImplicitDomainResult(
 			int valuesArrayPosition,
 			Consumer<SqlSelection> sqlSelectionConsumer,

hibernate-core/src/main/java/org/hibernate/query/results/complete/EntityResultImpl.java

@@ -6,19 +6,11 @@
  */
 package org.hibernate.query.results.complete;
 
-import java.util.Collections;
-import java.util.List;
 import java.util.function.Function;
 
 import org.hibernate.LockMode;
-import org.hibernate.engine.FetchTiming;
-import org.hibernate.internal.util.MutableObject;
-import org.hibernate.metamodel.mapping.EntityIdentifierMapping;
 import org.hibernate.metamodel.mapping.EntityValuedModelPart;
-import org.hibernate.metamodel.mapping.internal.SingleAttributeIdentifierMapping;
-import org.hibernate.spi.EntityIdentifierNavigablePath;
 import org.hibernate.spi.NavigablePath;
-import org.hibernate.query.results.ResultsHelper;
 import org.hibernate.sql.ast.spi.SqlAstCreationState;
 import org.hibernate.sql.results.graph.AssemblerCreationState;
 import org.hibernate.sql.results.graph.DomainResultAssembler;
@@ -28,10 +20,10 @@ import org.hibernate.sql.results.graph.FetchParentAccess;
 import org.hibernate.sql.results.graph.Fetchable;
 import org.hibernate.sql.results.graph.Initializer;
 import org.hibernate.sql.results.graph.basic.BasicFetch;
-import org.hibernate.sql.results.graph.entity.EntityInitializer;
 import org.hibernate.sql.results.graph.entity.EntityResult;
 import org.hibernate.sql.results.graph.entity.internal.EntityAssembler;
 import org.hibernate.sql.results.graph.entity.internal.EntityResultInitializer;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 
 /**
  * @author Steve Ebersole
@@ -42,12 +34,13 @@ public class EntityResultImpl implements EntityResult {
 
 	private final Fetch identifierFetch;
 	private final BasicFetch<?> discriminatorFetch;
-	private final List<Fetch> fetches;
+	private final ImmutableFetchList fetches;
+	private final boolean hasJoinFetches;
+	private final boolean containsCollectionFetches;
 
 	private final String resultAlias;
 	private final LockMode lockMode;
 
-	@SuppressWarnings( { "PointlessNullCheck" } )
 	public EntityResultImpl(
 			NavigablePath navigablePath,
 			EntityValuedModelPart entityValuedModelPart,
@@ -78,49 +71,12 @@ public class EntityResultImpl implements EntityResult {
 				}
 		);
 
+		this.identifierFetch = creationState.visitIdentifierFetch( this );
 		this.discriminatorFetch = discriminatorFetchBuilder.apply( this );
 
-		final List<Fetch> localFetches = creationState.visitFetches( this );
-
-		final EntityIdentifierMapping identifierMapping = entityValuedModelPart
-				.getEntityMappingType()
-				.getIdentifierMapping();
-		final String idAttributeName = identifierMapping instanceof SingleAttributeIdentifierMapping
-				? ( (SingleAttributeIdentifierMapping) identifierMapping ).getAttributeName()
-				: null;
-
-		final MutableObject<Fetch> idFetchRef = new MutableObject<>();
-
-		for ( int i = 0; i < localFetches.size(); i++ ) {
-			final Fetch fetch = localFetches.get( i );
-			final String fetchLocalName = fetch.getNavigablePath().getLocalName();
-
-			if ( fetchLocalName.equals( EntityIdentifierMapping.ROLE_LOCAL_NAME )
-					|| ( idAttributeName != null && fetchLocalName.equals( idAttributeName ) ) ) {
-				// we found the id fetch
-				idFetchRef.set( fetch );
-				localFetches.remove( i );
-				break;
-			}
-		}
-		this.fetches = Collections.unmodifiableList( localFetches );
-
-		if ( idFetchRef.isNotSet() ) {
-			identifierFetch = ( (Fetchable) identifierMapping ).generateFetch(
-					this,
-					new EntityIdentifierNavigablePath(
-							navigablePath,
-							ResultsHelper.attributeName( identifierMapping )
-					),
-					FetchTiming.IMMEDIATE,
-					true,
-					null,
-					creationState
-			);
-		}
-		else {
-			this.identifierFetch = idFetchRef.get();
-		}
+		this.fetches = creationState.visitFetches( this );
+		this.hasJoinFetches = fetches.hasJoinFetches();
+		this.containsCollectionFetches = fetches.containsCollectionFetches();
 	}
 
 	@Override
@@ -144,20 +100,23 @@ public class EntityResultImpl implements EntityResult {
 	}
 
 	@Override
-	public List<Fetch> getFetches() {
+	public ImmutableFetchList getFetches() {
 		return fetches;
 	}
 
 	@Override
 	public Fetch findFetch(Fetchable fetchable) {
-		final String name = fetchable.getFetchableName();
-		for ( int i = 0; i < fetches.size(); i++ ) {
-			final Fetch fetch = fetches.get( i );
-			if ( fetch.getFetchedMapping().getFetchableName().equals( name ) ) {
-				return fetch;
+		return fetches.get( fetchable );
 	}
+
+	@Override
+	public boolean hasJoinFetches() {
+		return hasJoinFetches;
 	}
-		return null;
+
+	@Override
+	public boolean containsCollectionFetches() {
+		return containsCollectionFetches;
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/query/results/dynamic/DynamicFetchBuilderLegacy.java

@@ -199,13 +199,13 @@ public class DynamicFetchBuilderLegacy implements DynamicFetchBuilder, NativeQue
 			}
 		}
 		try {
-			final NavigablePath currentRelativePath = creationState.getCurrentRelativePath();
+			final Map.Entry<String, NavigablePath> currentRelativePath = creationState.getCurrentRelativePath();
 			final String prefix;
 			if ( currentRelativePath == null ) {
 				prefix = "";
 			}
 			else {
-				prefix = currentRelativePath.getFullPath()
+				prefix = currentRelativePath.getKey()
 						.replace( ELEMENT_PREFIX, "" )
 						.replace( INDEX_PREFIX, "" ) + ".";
 			}

hibernate-core/src/main/java/org/hibernate/query/results/dynamic/DynamicFetchBuilderStandard.java

@@ -14,13 +14,11 @@ import org.hibernate.engine.FetchTiming;
 import org.hibernate.metamodel.mapping.BasicValuedMapping;
 import org.hibernate.metamodel.mapping.PluralAttributeMapping;
 import org.hibernate.metamodel.mapping.SelectableConsumer;
-import org.hibernate.metamodel.mapping.internal.EmbeddedAttributeMapping;
 import org.hibernate.metamodel.mapping.internal.ToOneAttributeMapping;
 import org.hibernate.query.NativeQuery;
 import org.hibernate.spi.NavigablePath;
 import org.hibernate.query.results.DomainResultCreationStateImpl;
 import org.hibernate.query.results.ResultsHelper;
-import org.hibernate.query.results.ResultSetMappingSqlSelection;
 import org.hibernate.sql.ast.spi.SqlExpressionResolver;
 import org.hibernate.sql.ast.tree.from.TableGroup;
 import org.hibernate.sql.ast.tree.from.TableReference;
@@ -28,6 +26,7 @@ import org.hibernate.sql.results.graph.DomainResultCreationState;
 import org.hibernate.sql.results.graph.Fetch;
 import org.hibernate.sql.results.graph.FetchParent;
 import org.hibernate.sql.results.graph.Fetchable;
+import org.hibernate.sql.results.graph.embeddable.EmbeddableValuedFetchable;
 import org.hibernate.sql.results.jdbc.spi.JdbcValuesMetadata;
 
 import static org.hibernate.sql.ast.spi.SqlExpressionResolver.createColumnReferenceKey;
@@ -114,7 +113,7 @@ public class DynamicFetchBuilderStandard
 					creationStateImpl
 			);
 		}
-		else if ( attributeMapping instanceof EmbeddedAttributeMapping ) {
+		else if ( attributeMapping instanceof EmbeddableValuedFetchable ) {
 			attributeMapping.forEachSelectable( selectableConsumer );
 			return parent.generateFetchableFetch(
 					attributeMapping,

hibernate-core/src/main/java/org/hibernate/query/results/dynamic/DynamicResultBuilderEntityStandard.java

@@ -9,6 +9,7 @@ package org.hibernate.query.results.dynamic;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 import java.util.function.BiFunction;
 import java.util.function.Function;
@@ -279,13 +280,13 @@ public class DynamicResultBuilderEntityStandard
 		}
 
 		try {
-			final NavigablePath currentRelativePath = creationState.getCurrentRelativePath();
+			final Map.Entry<String, NavigablePath> currentRelativePath = creationState.getCurrentRelativePath();
 			final String prefix;
 			if ( currentRelativePath == null ) {
 				prefix = "";
 			}
 			else {
-				prefix = currentRelativePath.getFullPath()
+				prefix = currentRelativePath.getKey()
 						.replace( ELEMENT_PREFIX, "" )
 						.replace( INDEX_PREFIX, "" ) + ".";
 			}

hibernate-core/src/main/java/org/hibernate/query/results/implicit/ImplicitFetchBuilderEmbeddable.java

@@ -51,13 +51,13 @@ public class ImplicitFetchBuilderEmbeddable implements ImplicitFetchBuilder {
 		this.fetchPath = fetchPath;
 		this.fetchable = fetchable;
 		final DomainResultCreationStateImpl creationStateImpl = impl( creationState );
-		final NavigablePath relativePath = creationStateImpl.getCurrentRelativePath();
+		final Map.Entry<String, NavigablePath> relativePath = creationStateImpl.getCurrentRelativePath();
 		final Function<String, FetchBuilder> fetchBuilderResolver = creationStateImpl.getCurrentExplicitFetchMementoResolver();
 		final int size = fetchable.getNumberOfFetchables();
 		final Map<NavigablePath, FetchBuilder> fetchBuilders = CollectionHelper.linkedMapOfSize( size );
 		for ( int i = 0; i < size; i++ ) {
 			final Fetchable subFetchable = fetchable.getFetchable( i );
-			final NavigablePath subFetchPath = relativePath.append( subFetchable.getFetchableName() );
+			final NavigablePath subFetchPath = relativePath.getValue().append( subFetchable.getFetchableName() );
 			final FetchBuilder explicitFetchBuilder = fetchBuilderResolver.apply( subFetchPath.getFullPath() );
 			if ( explicitFetchBuilder == null ) {
 				fetchBuilders.put(

hibernate-core/src/main/java/org/hibernate/query/results/implicit/ImplicitFetchBuilderEntity.java

@@ -48,25 +48,25 @@ public class ImplicitFetchBuilderEntity implements ImplicitFetchBuilder {
 		this.fetchPath = fetchPath;
 		this.fetchable = fetchable;
 		final DomainResultCreationStateImpl creationStateImpl = impl( creationState );
-		final NavigablePath relativePath = creationStateImpl.getCurrentRelativePath();
+		final Map.Entry<String, NavigablePath> relativePath = creationStateImpl.getCurrentRelativePath();
 		final Function<String, FetchBuilder> fetchBuilderResolver = creationStateImpl.getCurrentExplicitFetchMementoResolver();
 		ForeignKeyDescriptor foreignKeyDescriptor = fetchable.getForeignKeyDescriptor();
 		final String associationKeyPropertyName;
 		final NavigablePath associationKeyFetchPath;
 		if ( fetchable.getReferencedPropertyName() == null ) {
 			associationKeyPropertyName = fetchable.getEntityMappingType().getIdentifierMapping().getPartName();
-			associationKeyFetchPath = relativePath.append( associationKeyPropertyName );
+			associationKeyFetchPath = relativePath.getValue().append( associationKeyPropertyName );
 		}
 		else {
 			associationKeyPropertyName = fetchable.getReferencedPropertyName();
-			NavigablePath path = relativePath;
+			NavigablePath path = relativePath.getValue();
 			for ( String part : associationKeyPropertyName.split( "\\." ) ) {
 				path = path.append( part );
 			}
 			associationKeyFetchPath = path;
 		}
 		final FetchBuilder explicitAssociationKeyFetchBuilder = fetchBuilderResolver
-				.apply( associationKeyFetchPath.getFullPath() );
+				.apply( relativePath.getKey() + "." + associationKeyPropertyName );
 		final Map<NavigablePath, FetchBuilder> fetchBuilders;
 		if ( explicitAssociationKeyFetchBuilder == null ) {
 			final MappingType partMappingType = foreignKeyDescriptor.getPartMappingType();

hibernate-core/src/main/java/org/hibernate/query/sqm/sql/BaseSqmToSqlAstConverter.java

@@ -383,6 +383,7 @@ import org.hibernate.sql.results.graph.FetchParent;
 import org.hibernate.sql.results.graph.Fetchable;
 import org.hibernate.sql.results.graph.FetchableContainer;
 import org.hibernate.sql.results.graph.instantiation.internal.DynamicInstantiation;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.sql.results.internal.SqlSelectionImpl;
 import org.hibernate.sql.results.internal.StandardEntityGraphTraversalStateImpl;
 import org.hibernate.type.BasicType;
@@ -7137,7 +7138,7 @@ public abstract class BaseSqmToSqlAstConverter<T extends Statement> extends Base
 //				.getOrMakeJavaDescriptor( namedClass );
 	}
 
-	public void addFetch(List<Fetch> fetches, FetchParent fetchParent, Fetchable fetchable, Boolean isKeyFetchable) {
+	private void addFetch(ImmutableFetchList.Builder fetches, FetchParent fetchParent, Fetchable fetchable, Boolean isKeyFetchable) {
 		final NavigablePath resolvedNavigablePath = fetchParent.resolveNavigablePath( fetchable );
 		final Map.Entry<Integer, List<SqlSelection>> sqlSelectionsToTrack = trackedFetchSelectionsForGroup.get( resolvedNavigablePath );
 		final int sqlSelectionStartIndexForFetch;
@@ -7333,28 +7334,28 @@ public abstract class BaseSqmToSqlAstConverter<T extends Statement> extends Base
 	}
 
 	@Override
-	public List<Fetch> visitNestedFetches(FetchParent fetchParent) {
+	public ImmutableFetchList visitNestedFetches(FetchParent fetchParent) {
 		final SqlAstQueryPartProcessingStateImpl processingState = (SqlAstQueryPartProcessingStateImpl) getCurrentProcessingState();
 		final FetchParent nestingFetchParent = processingState.getNestingFetchParent();
 		processingState.setNestingFetchParent( fetchParent );
-		final List<Fetch> fetches = visitFetches( fetchParent );
+		final ImmutableFetchList fetches = visitFetches( fetchParent );
 		processingState.setNestingFetchParent( nestingFetchParent );
 		return fetches;
 	}
 
 	@Override
-	public List<Fetch> visitFetches(FetchParent fetchParent) {
+	public ImmutableFetchList visitFetches(FetchParent fetchParent) {
 		final FetchableContainer referencedMappingContainer = fetchParent.getReferencedMappingContainer();
 		final int keySize = referencedMappingContainer.getNumberOfKeyFetchables();
 		final int size = referencedMappingContainer.getNumberOfFetchables();
-		final List<Fetch> fetches = CollectionHelper.arrayList( keySize + size );
+		final ImmutableFetchList.Builder fetches = new ImmutableFetchList.Builder( referencedMappingContainer );
 		for ( int i = 0; i < keySize; i++ ) {
 			addFetch( fetches, fetchParent, referencedMappingContainer.getKeyFetchable( i ), true );
 		}
 		for ( int i = 0; i < size; i++ ) {
 			addFetch( fetches, fetchParent, referencedMappingContainer.getFetchable( i ), false );
 		}
-		return fetches;
+		return fetches.build();
 	}
 
 	private boolean shouldExplicitFetch(Integer maxDepth, Fetchable fetchable) {

hibernate-core/src/main/java/org/hibernate/sql/results/graph/AbstractFetchParent.java

@@ -6,12 +6,9 @@
  */
 package org.hibernate.sql.results.graph;
 
-import java.util.Collections;
-import java.util.List;
-
 import org.hibernate.metamodel.mapping.EntityVersionMapping;
-import org.hibernate.metamodel.model.domain.NavigableRole;
 import org.hibernate.spi.NavigablePath;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.type.descriptor.java.JavaType;
 
 /**
@@ -21,7 +18,9 @@ public abstract class AbstractFetchParent implements FetchParent {
 	private final FetchableContainer fetchContainer;
 	private final NavigablePath navigablePath;
 
-	private List<Fetch> fetches;
+	private ImmutableFetchList fetches = ImmutableFetchList.EMPTY;
+	private boolean hasJoinFetches;
+	private boolean containsCollectionFetches;
 
 	public AbstractFetchParent(FetchableContainer fetchContainer, NavigablePath navigablePath) {
 		this.fetchContainer = fetchContainer;
@@ -29,12 +28,14 @@ public abstract class AbstractFetchParent implements FetchParent {
 	}
 
 	public void afterInitialize(FetchParent fetchParent, DomainResultCreationState creationState) {
-		assert fetches == null;
+		assert fetches == ImmutableFetchList.EMPTY;
 		resetFetches( creationState.visitFetches( fetchParent ) );
 	}
 
-	protected void resetFetches(final List<Fetch> newFetches) {
-		this.fetches = Collections.unmodifiableList( newFetches );
+	protected void resetFetches(ImmutableFetchList newFetches) {
+		this.fetches = newFetches;
+		this.hasJoinFetches = newFetches.hasJoinFetches();
+		this.containsCollectionFetches = newFetches.containsCollectionFetches();
 	}
 
 	public FetchableContainer getFetchContainer() {
@@ -57,35 +58,25 @@ public abstract class AbstractFetchParent implements FetchParent {
 	}
 
 	@Override
-	public List<Fetch> getFetches() {
-		return fetches == null ? Collections.emptyList() : fetches;
+	public ImmutableFetchList getFetches() {
+		return fetches;
 	}
 
 	@Override
 	public Fetch findFetch(final Fetchable fetchable) {
-		if ( fetches == null ) {
-			return null;
-		}
-
-		//Iterate twice so we can perform the cheapest checks on each item first:
-		for ( int i = 0; i < fetches.size(); i++ ) {
-			final Fetch fetch = fetches.get( i );
-			if ( fetchable == fetch.getFetchedMapping() ) {
-				return fetch;
-			}
-		}
-
 		if ( fetchable instanceof EntityVersionMapping ) {
-			//Second iteration performs the slightly more expensive checks, necessary for EntityVersionMapping:
-			final NavigableRole navigableRole = fetchable.getNavigableRole();
-			for ( int i = 0; i < fetches.size(); i++ ) {
-				final Fetch fetch = fetches.get( i );
-				if ( fetch.getFetchedMapping().getNavigableRole().equals( navigableRole ) ) {
-					return fetch;
-				}
+			return fetches.get( ( (EntityVersionMapping) fetchable ).getVersionAttribute() );
 		}
+		return fetches.get( fetchable );
 	}
 
-		return null;
+	@Override
+	public boolean hasJoinFetches() {
+		return hasJoinFetches;
+	}
+
+	@Override
+	public boolean containsCollectionFetches() {
+		return containsCollectionFetches;
 	}
 }

hibernate-core/src/main/java/org/hibernate/sql/results/graph/DomainResultCreationState.java

@@ -9,12 +9,22 @@ package org.hibernate.sql.results.graph;
 import java.util.List;
 
 import org.hibernate.Incubating;
+import org.hibernate.engine.FetchTiming;
 import org.hibernate.metamodel.mapping.AssociationKey;
+import org.hibernate.metamodel.mapping.EntityDiscriminatorMapping;
+import org.hibernate.metamodel.mapping.EntityIdentifierMapping;
+import org.hibernate.metamodel.mapping.EntityMappingType;
 import org.hibernate.metamodel.mapping.ForeignKeyDescriptor;
 import org.hibernate.metamodel.mapping.ModelPart;
+import org.hibernate.spi.EntityIdentifierNavigablePath;
 import org.hibernate.spi.NavigablePath;
 import org.hibernate.sql.ast.spi.SqlAliasBaseManager;
 import org.hibernate.sql.ast.spi.SqlAstCreationState;
+import org.hibernate.sql.results.graph.basic.BasicFetch;
+import org.hibernate.sql.results.graph.entity.EntityResultGraphNode;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
+
+import static org.hibernate.query.results.ResultsHelper.attributeName;
 
 /**
  * Contains state related to building {@link DomainResult} and
@@ -77,6 +87,39 @@ public interface DomainResultCreationState {
 	 */
 	ModelPart resolveModelPart(NavigablePath navigablePath);
 
+	default Fetch visitIdentifierFetch(EntityResultGraphNode fetchParent) {
+		final EntityIdentifierMapping identifierMapping = fetchParent.getEntityValuedModelPart()
+				.getEntityMappingType()
+				.getIdentifierMapping();
+		return fetchParent.generateFetchableFetch(
+				(Fetchable) identifierMapping,
+				new EntityIdentifierNavigablePath( fetchParent.getNavigablePath(), attributeName( identifierMapping ) ),
+				FetchTiming.IMMEDIATE,
+				true,
+				null,
+				this
+		);
+	}
+
+	default BasicFetch<?> visitDiscriminatorFetch(EntityResultGraphNode fetchParent) {
+		final EntityMappingType entityDescriptor = fetchParent.getEntityValuedModelPart().getEntityMappingType();
+		final EntityDiscriminatorMapping discriminatorMapping = entityDescriptor.getDiscriminatorMapping();
+		// No need to fetch the discriminator if this type does not have subclasses
+		if ( discriminatorMapping != null && entityDescriptor.hasSubclasses() ) {
+			return discriminatorMapping.generateFetch(
+					fetchParent,
+					fetchParent.getNavigablePath().append( EntityDiscriminatorMapping.ROLE_NAME ),
+					FetchTiming.IMMEDIATE,
+					true,
+					null,
+					this
+			);
+		}
+		else {
+			return null;
+		}
+	}
+
 	/**
 	 * Visit fetches for the given parent.
 	 *
@@ -108,9 +151,9 @@ public interface DomainResultCreationState {
 	 * 		are built/accessed.  Comes down to how we'd know whether to join fetch or select fetch.  Simply pass
 	 * 		along FetchStyle?
  	 */
-	List<Fetch> visitFetches(FetchParent fetchParent);
+	ImmutableFetchList visitFetches(FetchParent fetchParent);
 
-	List<Fetch> visitNestedFetches(FetchParent fetchParent);
+	ImmutableFetchList visitNestedFetches(FetchParent fetchParent);
 
 	boolean isResolvingCircularFetch();
 

hibernate-core/src/main/java/org/hibernate/sql/results/graph/DomainResultGraphPrinter.java

@@ -6,6 +6,7 @@
  */
 package org.hibernate.sql.results.graph;
 
+import java.util.Iterator;
 import java.util.List;
 
 import org.hibernate.internal.log.SubSystemLogging;
@@ -114,12 +115,9 @@ public class DomainResultGraphPrinter {
 //				visitKeyGraphNode( identifierFetch, lastInBranch );
 //			}
 
-			final int numberOfFetches = fetchParent.getFetches().size();
-
-			for ( int i = 0; i < numberOfFetches; i++ ) {
-				final Fetch fetch = fetchParent.getFetches().get( i );
-
-				final boolean lastInBranch = i + 1 == numberOfFetches;
+			for ( Iterator<Fetch> iterator = fetchParent.getFetches().iterator(); iterator.hasNext(); ) {
+				final Fetch fetch = iterator.next();
+				final boolean lastInBranch = !iterator.hasNext();
 				visitGraphNode( fetch, lastInBranch );
 			}
 		}

hibernate-core/src/main/java/org/hibernate/sql/results/graph/FetchList.java

@@ -0,0 +1,83 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.sql.results.graph;
+
+import java.util.function.Consumer;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+import org.hibernate.Incubating;
+import org.hibernate.engine.FetchTiming;
+import org.hibernate.mapping.IndexedConsumer;
+import org.hibernate.metamodel.mapping.AttributeMapping;
+import org.hibernate.sql.results.graph.basic.BasicFetch;
+import org.hibernate.sql.results.graph.collection.internal.EagerCollectionFetch;
+import org.hibernate.sql.results.graph.embeddable.EmbeddableResultGraphNode;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
+
+/**
+ * This is essentially a List of Fetch(es), but exposing
+ * an interface which is more suitable to our needs; in particular
+ * it expresses the immutable nature of this structure, and allows
+ * us to extend it with additional convenience methods such as
+ * {@link #indexedForEach(IndexedConsumer)}.
+ * And additional reason for the custom interface is to allow
+ * custom implementations which can be highly optimised as
+ * necessary for our specific needs; for example the
+ * implementation {@link org.hibernate.sql.results.graph.internal.ImmutableFetchList}
+ * is able to avoid caching problems related to JDK-8180450, which would
+ * not have been possible with a standard generic container.
+ * @since 6.2
+ */
+@Incubating
+public interface FetchList extends Iterable<Fetch> {
+
+	int size();
+
+	boolean isEmpty();
+
+	Fetch get(Fetchable fetchable);
+
+	void forEach(Consumer<? super Fetch> consumer);
+
+	void indexedForEach(IndexedConsumer<? super Fetch> consumer);
+
+	default Stream<Fetch> stream() {
+		return StreamSupport.stream( spliterator(), false );
+	}
+
+	default boolean hasJoinFetches() {
+		for ( Fetch fetch : this ) {
+			if ( fetch instanceof BasicFetch<?> || fetch.getTiming() == FetchTiming.DELAYED ) {
+				// That's fine
+			}
+			else if ( fetch instanceof EmbeddableResultGraphNode ) {
+				// Check all these fetches as well
+				if ( ( (EmbeddableResultGraphNode) fetch ).hasJoinFetches() ) {
+					return true;
+				}
+			}
+			else {
+				return true;
+			}
+		}
+		return false;
+	}
+
+	default boolean containsCollectionFetches() {
+		for ( Fetch fetch : this ) {
+			if ( fetch instanceof EagerCollectionFetch ) {
+				return true;
+			}
+			else if ( fetch instanceof FetchParent && ( (FetchParent) fetch ).containsCollectionFetches() ) {
+				return true;
+			}
+		}
+		return false;
+	}
+
+}

hibernate-core/src/main/java/org/hibernate/sql/results/graph/FetchParent.java

@@ -6,8 +6,6 @@
  */
 package org.hibernate.sql.results.graph;
 
-import java.util.List;
-
 import org.hibernate.Incubating;
 import org.hibernate.engine.FetchTiming;
 import org.hibernate.metamodel.mapping.EmbeddableMappingType;
@@ -17,6 +15,7 @@ import org.hibernate.metamodel.mapping.ModelPart;
 import org.hibernate.metamodel.mapping.internal.ToOneAttributeMapping;
 import org.hibernate.spi.EntityIdentifierNavigablePath;
 import org.hibernate.spi.NavigablePath;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 
 /**
  * Contract for things that can be the parent of a fetch
@@ -84,10 +83,14 @@ public interface FetchParent extends DomainResultGraphNode {
 	/**
 	 * Retrieve the fetches owned by this fetch source.
 	 */
-	List<Fetch> getFetches();
+	ImmutableFetchList getFetches();
 
 	Fetch findFetch(Fetchable fetchable);
 
+	boolean hasJoinFetches();
+
+	boolean containsCollectionFetches();
+
 	default FetchParent getRoot() {
 		if ( this instanceof Fetch ) {
 			return ( (Fetch) this ).getFetchParent().getRoot();

hibernate-core/src/main/java/org/hibernate/sql/results/graph/Fetchable.java

@@ -8,7 +8,9 @@ package org.hibernate.sql.results.graph;
 
 import org.hibernate.Incubating;
 import org.hibernate.engine.FetchTiming;
+import org.hibernate.mapping.IndexedConsumer;
 import org.hibernate.metamodel.mapping.AttributeMapping;
+import org.hibernate.metamodel.mapping.EntityMappingType;
 import org.hibernate.metamodel.mapping.ModelPart;
 import org.hibernate.spi.NavigablePath;
 
@@ -24,6 +26,16 @@ public interface Fetchable extends ModelPart {
 	 */
 	String getFetchableName();
 
+	/**
+	 * The key that identifies this {@linkplain Fetchable} within a {@link FetchableContainer}.
+	 * If this {@linkplain Fetchable} is part of {@link FetchableContainer#visitFetchables(IndexedConsumer, EntityMappingType)},
+	 * the values is guaranteed to be between 0 (inclusive) and {@link FetchableContainer#getNumberOfFetchableKeys()} (exclusive).
+	 * Other {@linkplain Fetchable} objects may have a special negative value.
+	 * <p>
+	 * The main intent of this key is to index e.g. {@link Fetch} objects in an array.
+	 */
+	int getFetchableKey();
+
 	/**
 	 * The configured fetch timing and style
 	 */

hibernate-core/src/main/java/org/hibernate/sql/results/graph/FetchableContainer.java

@@ -34,6 +34,13 @@ public interface FetchableContainer extends ModelPartContainer {
 	 */
 	int getNumberOfFetchables();
 
+	/**
+	 * The number of fetchables in the container
+	 */
+	default int getNumberOfFetchableKeys() {
+		return getNumberOfFetchables();
+	}
+
 	default Fetchable getKeyFetchable(int position) {
 		List<Fetchable> fetchables = new ArrayList<>( getNumberOfKeyFetchables() );
 		visitKeyFetchables( fetchable -> fetchables.add( fetchable ), null );

hibernate-core/src/main/java/org/hibernate/sql/results/graph/collection/internal/CollectionDomainResult.java

@@ -26,6 +26,7 @@ import org.hibernate.sql.results.graph.Fetchable;
 import org.hibernate.sql.results.graph.FetchableContainer;
 import org.hibernate.sql.results.graph.collection.CollectionInitializer;
 import org.hibernate.sql.results.graph.collection.CollectionResultGraphNode;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.type.descriptor.java.JavaType;
 
 /**
@@ -127,8 +128,8 @@ public class CollectionDomainResult implements DomainResult, CollectionResultGra
 	}
 
 	@Override
-	public List<Fetch> getFetches() {
-		return Collections.emptyList();
+	public ImmutableFetchList getFetches() {
+		return ImmutableFetchList.EMPTY;
 	}
 
 	@Override
@@ -136,4 +137,14 @@ public class CollectionDomainResult implements DomainResult, CollectionResultGra
 		return null;
 	}
 
+	@Override
+	public boolean hasJoinFetches() {
+		return false;
+	}
+
+	@Override
+	public boolean containsCollectionFetches() {
+		return false;
+	}
+
 }

hibernate-core/src/main/java/org/hibernate/sql/results/graph/collection/internal/EagerCollectionFetch.java

@@ -23,11 +23,13 @@ import org.hibernate.sql.results.graph.DomainResult;
 import org.hibernate.sql.results.graph.DomainResultAssembler;
 import org.hibernate.sql.results.graph.DomainResultCreationState;
 import org.hibernate.sql.results.graph.Fetch;
+import org.hibernate.sql.results.graph.FetchList;
 import org.hibernate.sql.results.graph.FetchParent;
 import org.hibernate.sql.results.graph.FetchParentAccess;
 import org.hibernate.sql.results.graph.Fetchable;
 import org.hibernate.sql.results.graph.FetchableContainer;
 import org.hibernate.sql.results.graph.collection.CollectionInitializer;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.type.descriptor.java.JavaType;
 
 /**
@@ -40,7 +42,7 @@ public class EagerCollectionFetch extends CollectionFetch implements FetchParent
 	private final Fetch elementFetch;
 	private final Fetch indexFetch;
 
-	private final List<Fetch> fetches;
+	private final ImmutableFetchList fetches;
 
 	private final CollectionInitializerProducer initializerProducer;
 
@@ -104,17 +106,17 @@ public class EagerCollectionFetch extends CollectionFetch implements FetchParent
 				creationState
 		);
 
-		fetches = Collections.unmodifiableList( creationState.visitFetches( this ) );
+		fetches = creationState.visitFetches( this );
 		if ( fetchedAttribute.getIndexDescriptor() != null ) {
 			assert fetches.size() == 2;
-			indexFetch = fetches.get( 0 );
-			elementFetch = fetches.get( 1 );
+			indexFetch = fetches.get( fetchedAttribute.getIndexDescriptor() );
+			elementFetch = fetches.get( fetchedAttribute.getElementDescriptor() );
 		}
 		else {
 			if ( !fetches.isEmpty() ) { // might be empty due to fetch depth limit
 				assert fetches.size() == 1;
 				indexFetch = null;
-				elementFetch = fetches.get( 0 );
+				elementFetch = fetches.get( fetchedAttribute.getElementDescriptor() );
 			}
 			else {
 				indexFetch = null;
@@ -180,7 +182,7 @@ public class EagerCollectionFetch extends CollectionFetch implements FetchParent
 	}
 
 	@Override
-	public List<Fetch> getFetches() {
+	public ImmutableFetchList getFetches() {
 		return fetches;
 	}
 
@@ -200,6 +202,18 @@ public class EagerCollectionFetch extends CollectionFetch implements FetchParent
 		}
 	}
 
+	@Override
+	public boolean hasJoinFetches() {
+		// This is already a fetch, so this line should actually never be hit
+		return true;
+	}
+
+	@Override
+	public boolean containsCollectionFetches() {
+		// This is already a collection fetch, so this line should actually never be hit
+		return true;
+	}
+
 	@Override
 	public JavaType<?> getResultJavaType() {
 		return getFetchedMapping().getJavaType();

hibernate-core/src/main/java/org/hibernate/sql/results/graph/embeddable/internal/AggregateEmbeddableResultImpl.java

@@ -32,6 +32,7 @@ import org.hibernate.sql.results.graph.FetchParentAccess;
 import org.hibernate.sql.results.graph.embeddable.EmbeddableInitializer;
 import org.hibernate.sql.results.graph.embeddable.EmbeddableResult;
 import org.hibernate.sql.results.graph.embeddable.EmbeddableResultGraphNode;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.type.descriptor.java.JavaType;
 import org.hibernate.type.descriptor.jdbc.AggregateJdbcType;
 import org.hibernate.type.spi.TypeConfiguration;
@@ -106,9 +107,9 @@ public class AggregateEmbeddableResultImpl<T> extends AbstractFetchParent implem
 		this.containsAnyNonScalars = determineIfContainedAnyScalars( getFetches() );
 	}
 
-	private static boolean determineIfContainedAnyScalars(List<Fetch> fetches) {
-		for ( int i = 0; i < fetches.size(); i++ ) {
-			if ( fetches.get( i ).containsAnyNonScalarResults() ) {
+	private static boolean determineIfContainedAnyScalars(ImmutableFetchList fetches) {
+		for ( Fetch fetch : fetches ) {
+			if ( fetch.containsAnyNonScalarResults() ) {
 				return true;
 			}
 		}

hibernate-core/src/main/java/org/hibernate/sql/results/graph/embeddable/internal/EmbeddableExpressionResultImpl.java

@@ -6,23 +6,15 @@
  */
 package org.hibernate.sql.results.graph.embeddable.internal;
 
-import java.util.ArrayList;
-import java.util.List;
-
 import org.hibernate.engine.FetchTiming;
-import org.hibernate.metamodel.mapping.AttributeMapping;
 import org.hibernate.metamodel.mapping.EmbeddableMappingType;
 import org.hibernate.metamodel.mapping.EmbeddableValuedModelPart;
 import org.hibernate.metamodel.mapping.internal.BasicAttributeMapping;
 import org.hibernate.spi.NavigablePath;
-import org.hibernate.sql.ast.SqlAstJoinType;
-import org.hibernate.sql.ast.spi.FromClauseAccess;
 import org.hibernate.sql.ast.spi.SqlAstCreationState;
 import org.hibernate.sql.ast.spi.SqlExpressionResolver;
 import org.hibernate.sql.ast.spi.SqlSelection;
 import org.hibernate.sql.ast.tree.expression.SqlTuple;
-import org.hibernate.sql.ast.tree.from.TableGroup;
-import org.hibernate.sql.ast.tree.from.TableGroupJoin;
 import org.hibernate.sql.results.graph.AbstractFetchParent;
 import org.hibernate.sql.results.graph.AssemblerCreationState;
 import org.hibernate.sql.results.graph.DomainResult;
@@ -34,6 +26,7 @@ import org.hibernate.sql.results.graph.basic.BasicFetch;
 import org.hibernate.sql.results.graph.embeddable.EmbeddableInitializer;
 import org.hibernate.sql.results.graph.embeddable.EmbeddableResult;
 import org.hibernate.sql.results.graph.embeddable.EmbeddableResultGraphNode;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.type.descriptor.java.JavaType;
 import org.hibernate.type.spi.TypeConfiguration;
 
@@ -53,7 +46,7 @@ public class EmbeddableExpressionResultImpl<T> extends AbstractFetchParent imple
 		super( modelPart.getEmbeddableTypeDescriptor(), navigablePath );
 		this.resultVariable = resultVariable;
 
-		final List<Fetch> fetches = new ArrayList<>();
+		final ImmutableFetchList.Builder fetches = new ImmutableFetchList.Builder( modelPart );
 		final EmbeddableMappingType mappingType = modelPart.getEmbeddableTypeDescriptor();
 		final int numberOfAttributeMappings = mappingType.getNumberOfAttributeMappings();
 		final SqlAstCreationState sqlAstCreationState = creationState.getSqlAstCreationState();
@@ -81,13 +74,13 @@ public class EmbeddableExpressionResultImpl<T> extends AbstractFetchParent imple
 			);
 		}
 
-		this.containsAnyNonScalars = determineIfContainedAnyScalars( fetches );
-		resetFetches( fetches );
+		resetFetches( fetches.build() );
+		this.containsAnyNonScalars = determineIfContainedAnyScalars( getFetches() );
 	}
 
-	private static boolean determineIfContainedAnyScalars(List<Fetch> fetches) {
-		for ( int i = 0; i < fetches.size(); i++ ) {
-			if ( fetches.get( i ).containsAnyNonScalarResults() ) {
+	private static boolean determineIfContainedAnyScalars(ImmutableFetchList fetches) {
+		for ( Fetch fetch : fetches ) {
+			if ( fetch.containsAnyNonScalarResults() ) {
 				return true;
 			}
 		}

hibernate-core/src/main/java/org/hibernate/sql/results/graph/embeddable/internal/EmbeddableResultImpl.java

@@ -25,6 +25,7 @@ import org.hibernate.sql.results.graph.FetchParentAccess;
 import org.hibernate.sql.results.graph.embeddable.EmbeddableInitializer;
 import org.hibernate.sql.results.graph.embeddable.EmbeddableResult;
 import org.hibernate.sql.results.graph.embeddable.EmbeddableResultGraphNode;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 import org.hibernate.type.descriptor.java.JavaType;
 
 /**
@@ -76,9 +77,9 @@ public class EmbeddableResultImpl<T> extends AbstractFetchParent implements Embe
 		containsAnyNonScalars = determineIfContainedAnyScalars( getFetches() );
 	}
 
-	private static boolean determineIfContainedAnyScalars(List<Fetch> fetches) {
-		for ( int i = 0; i < fetches.size(); i++ ) {
-			if ( fetches.get( i ).containsAnyNonScalarResults() ) {
+	private static boolean determineIfContainedAnyScalars(ImmutableFetchList fetches) {
+		for ( Fetch fetch : fetches ) {
+			if ( fetch.containsAnyNonScalarResults() ) {
 				return true;
 			}
 		}

hibernate-core/src/main/java/org/hibernate/sql/results/graph/entity/AbstractEntityResultGraphNode.java

@@ -53,37 +53,20 @@ public abstract class AbstractEntityResultGraphNode extends AbstractFetchParent
 		final NavigablePath navigablePath = getNavigablePath();
 		final TableGroup entityTableGroup = creationState.getSqlAstCreationState().getFromClauseAccess()
 				.getTableGroup( navigablePath );
-		final EntityIdentifierNavigablePath identifierNavigablePath = new EntityIdentifierNavigablePath( navigablePath, attributeName( identifierMapping ) );
 		if ( navigablePath.getParent() == null && !creationState.forceIdentifierSelection() ) {
 			identifierFetch = null;
-			visitIdentifierMapping( identifierNavigablePath, creationState, identifierMapping, entityTableGroup );
+			visitIdentifierMapping(
+					new EntityIdentifierNavigablePath( navigablePath, attributeName( identifierMapping ) ),
+					creationState,
+					identifierMapping,
+					entityTableGroup
+			);
 		}
 		else {
-			identifierFetch = ( (Fetchable) identifierMapping ).generateFetch(
-					fetchParent,
-					identifierNavigablePath,
-					FetchTiming.IMMEDIATE,
-					true,
-					null,
-					creationState
-			);
+			identifierFetch = creationState.visitIdentifierFetch( this );
 		}
 
-		final EntityDiscriminatorMapping discriminatorMapping = entityDescriptor.getDiscriminatorMapping();
-		// No need to fetch the discriminator if this type does not have subclasses
-		if ( discriminatorMapping != null && entityDescriptor.hasSubclasses() ) {
-			discriminatorFetch = discriminatorMapping.generateFetch(
-					fetchParent,
-					navigablePath.append( EntityDiscriminatorMapping.ROLE_NAME ),
-					FetchTiming.IMMEDIATE,
-					true,
-					null,
-					creationState
-			);
-		}
-		else {
-			discriminatorFetch = null;
-		}
+		discriminatorFetch = creationState.visitDiscriminatorFetch( this );
 
 		final EntityRowIdMapping rowIdMapping = entityDescriptor.getRowIdMapping();
 		if ( rowIdMapping == null ) {

hibernate-core/src/main/java/org/hibernate/sql/results/graph/entity/internal/AbstractNonJoinedEntityFetch.java

@@ -16,6 +16,7 @@ import org.hibernate.sql.results.graph.FetchParent;
 import org.hibernate.sql.results.graph.Fetchable;
 import org.hibernate.sql.results.graph.entity.EntityFetch;
 import org.hibernate.sql.results.graph.entity.EntityValuedFetchable;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 
 /**
  * @author Steve Ebersole
@@ -55,8 +56,8 @@ public abstract class AbstractNonJoinedEntityFetch implements EntityFetch {
 	}
 
 	@Override
-	public List<Fetch> getFetches() {
-		return Collections.emptyList();
+	public ImmutableFetchList getFetches() {
+		return ImmutableFetchList.EMPTY;
 	}
 
 	@Override
@@ -64,6 +65,16 @@ public abstract class AbstractNonJoinedEntityFetch implements EntityFetch {
 		return null;
 	}
 
+	@Override
+	public boolean hasJoinFetches() {
+		return false;
+	}
+
+	@Override
+	public boolean containsCollectionFetches() {
+		return false;
+	}
+
 	@Override
 	public EntityMappingType getReferencedMappingType() {
 		return fetchedModelPart.getEntityMappingType();

hibernate-core/src/main/java/org/hibernate/sql/results/graph/internal/ImmutableFetchList.java

@@ -0,0 +1,141 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.sql.results.graph.internal;
+
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.function.Consumer;
+
+import org.hibernate.mapping.IndexedConsumer;
+import org.hibernate.metamodel.mapping.AttributeMapping;
+import org.hibernate.persister.internal.ImmutableAttributeMappingList;
+import org.hibernate.sql.results.graph.Fetch;
+import org.hibernate.sql.results.graph.FetchList;
+import org.hibernate.sql.results.graph.Fetchable;
+import org.hibernate.sql.results.graph.FetchableContainer;
+
+public final class ImmutableFetchList implements FetchList {
+
+	public static ImmutableFetchList EMPTY = new ImmutableFetchList();
+	private final Fetch[] fetches;
+
+	private ImmutableFetchList() {
+		this.fetches = null;
+	}
+
+	private ImmutableFetchList(Fetch[] fetches) {
+		assert fetches != null;
+		this.fetches = fetches;
+	}
+
+	@Override
+	public int size() {
+		if ( fetches == null ) {
+			return 0;
+		}
+		int size = 0;
+		for ( Fetch fetch : fetches ) {
+			if ( fetch != null ) {
+				size++;
+			}
+		}
+		return size;
+	}
+
+	@Override
+	public boolean isEmpty() {
+		return fetches == null;
+	}
+
+	@Override
+	public Fetch get(Fetchable fetchable) {
+		return fetches == null ? null : fetches[fetchable.getFetchableKey()];
+	}
+
+	@Override
+	public void forEach(Consumer<? super Fetch> consumer) {
+		if ( fetches != null ) {
+			for ( Fetch fetch : fetches ) {
+				if ( fetch != null ) {
+					consumer.accept( fetch );
+				}
+			}
+		}
+	}
+
+	@Override
+	public void indexedForEach(IndexedConsumer<? super Fetch> consumer) {
+		if ( fetches != null ) {
+			int index = 0;
+			for ( Fetch fetch : fetches ) {
+				if ( fetch != null ) {
+					consumer.accept( index++, fetch );
+				}
+			}
+		}
+	}
+
+	@Override
+	public Iterator<Fetch> iterator() {
+		if ( fetches == null ) {
+			return Collections.emptyIterator();
+		}
+		return new FetchIterator();
+	}
+
+	private final class FetchIterator implements Iterator<Fetch> {
+
+		private int idx;
+
+		public FetchIterator() {
+			assert ImmutableFetchList.this.fetches != null;
+			this.idx = 0;
+			while (ImmutableFetchList.this.fetches[idx] == null) {
+				idx++;
+			}
+		}
+
+		@Override
+		public boolean hasNext() {
+			return idx < ImmutableFetchList.this.fetches.length;
+		}
+
+		@Override
+		public Fetch next() {
+			final Fetch fetch = ImmutableFetchList.this.fetches[idx++];
+			while ( idx < ImmutableFetchList.this.fetches.length ) {
+				if ( ImmutableFetchList.this.fetches[idx] != null ) {
+					break;
+				}
+				idx++;
+			}
+			return fetch;
+		}
+
+	}
+
+	public static class Builder {
+		private final Fetch[] fetches;
+
+		public Builder(FetchableContainer container) {
+			this.fetches = new Fetch[container.getNumberOfFetchableKeys()];
+		}
+
+		public void add(Fetch fetch) {
+			fetches[fetch.getFetchedMapping().getFetchableKey()] = fetch;
+		}
+
+		public ImmutableFetchList build() {
+			for ( Fetch fetch : fetches ) {
+				if ( fetch != null ) {
+					return new ImmutableFetchList( fetches );
+				}
+			}
+			return EMPTY;
+		}
+	}
+}

hibernate-core/src/main/java/org/hibernate/sql/results/spi/ScrollableResultsConsumer.java

@@ -12,8 +12,6 @@ import org.hibernate.engine.spi.SharedSessionContractImplementor;
 import org.hibernate.internal.FetchingScrollableResultsImpl;
 import org.hibernate.internal.ScrollableResultsImpl;
 import org.hibernate.sql.results.graph.DomainResult;
-import org.hibernate.sql.results.graph.Fetch;
-import org.hibernate.sql.results.graph.collection.internal.EagerCollectionFetch;
 import org.hibernate.sql.results.graph.entity.EntityResult;
 import org.hibernate.sql.results.jdbc.spi.JdbcValuesMapping;
 import org.hibernate.sql.results.jdbc.spi.JdbcValues;
@@ -74,17 +72,11 @@ public class ScrollableResultsConsumer<R> implements ResultsConsumer<ScrollableR
 
 	private boolean containsCollectionFetches(JdbcValuesMapping valuesMapping) {
 		final List<DomainResult<?>> domainResults = valuesMapping.getDomainResults();
-		for ( DomainResult domainResult : domainResults ) {
-			if ( domainResult instanceof EntityResult ) {
-				EntityResult entityResult = (EntityResult) domainResult;
-				final List<Fetch> fetches = entityResult.getFetches();
-				for ( Fetch fetch : fetches ) {
-					if ( fetch instanceof EagerCollectionFetch ) {
+		for ( DomainResult<?> domainResult : domainResults ) {
+			if ( domainResult instanceof EntityResult && ( (EntityResult) domainResult ).containsCollectionFetches() ) {
 				return true;
 			}
 		}
-			}
-		}
 		return false;
 	}
 }

hibernate-core/src/test/java/org/hibernate/orm/test/entitygraph/ast/CriteriaEntityGraphTest.java

@@ -54,6 +54,7 @@ import org.hibernate.sql.results.graph.entity.EntityFetch;
 import org.hibernate.sql.results.graph.entity.EntityResult;
 import org.hibernate.sql.results.graph.entity.internal.EntityDelayedFetchImpl;
 import org.hibernate.sql.results.graph.entity.internal.EntityFetchJoinedImpl;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 
 import org.hibernate.testing.TestForIssue;
 import org.hibernate.testing.orm.junit.DomainModel;
@@ -190,13 +191,12 @@ public class CriteriaEntityGraphTest implements SessionFactoryScopeAware {
 						Fetchable fetchable = getFetchable( "company", Person.class );
 
 						final Fetch companyFetch = ownerEntityResult.findFetch( fetchable );
-						List<Fetch> fetches = ownerEntityResult.getFetches();
 						assertThat( companyFetch, notNullValue() );
 
 						final EntityResult companyEntityResult = ( (EntityFetchJoinedImpl) companyFetch).getEntityResult();
-						assertThat( companyEntityResult.getFetches(), hasSize( 1 ) );
+						assertThat( companyEntityResult.getFetches().size(), is( 1 ) );
 
-						final Fetch shipAddressesFetch = companyEntityResult.getFetches().get( 0 );
+						final Fetch shipAddressesFetch = companyEntityResult.getFetches().iterator().next();
 						assertThat( shipAddressesFetch.getFetchedMapping().getPartName(), is( "shipAddresses" ) );
 						assertThat( shipAddressesFetch, instanceOf( DelayedCollectionFetch.class ) );
 					} );
@@ -348,9 +348,9 @@ public class CriteriaEntityGraphTest implements SessionFactoryScopeAware {
 
 		final EntityResult entityResult = (EntityResult) domainResult;
 		assertThat( entityResult.getReferencedModePart().getJavaType().getJavaTypeClass(), assignableTo( expectedEntityJpaClass ) );
-		assertThat( entityResult.getFetches(), hasSize( 1 ) );
+		assertThat( entityResult.getFetches().size(), is( 1 ) );
 
-		final Fetch fetch = entityResult.getFetches().get( 0 );
+		final Fetch fetch = entityResult.getFetches().iterator().next();
 		assertThat( fetch, instanceOf( EntityFetch.class ) );
 
 		final EntityFetch entityFetch = (EntityFetch) fetch;

hibernate-core/src/test/java/org/hibernate/orm/test/entitygraph/ast/EntityGraphLoadPlanBuilderTest.java

@@ -189,9 +189,9 @@ public class EntityGraphLoadPlanBuilderTest implements SessionFactoryScopeAware
 						assertThat( companyFetch, notNullValue() );
 
 						final EntityResult companyEntityResult = ( (EntityFetchJoinedImpl) companyFetch).getEntityResult();
-						assertThat( companyEntityResult.getFetches(), hasSize( 1 ) );
+						assertThat( companyEntityResult.getFetches().size(), is( 1 ) );
 
-						final Fetch shipAddressesFetch = companyEntityResult.getFetches().get( 0 );
+						final Fetch shipAddressesFetch = companyEntityResult.getFetches().iterator().next();
 						assertThat( shipAddressesFetch.getFetchedMapping().getPartName(), is( "shipAddresses" ) );
 						assertThat( shipAddressesFetch, instanceOf( DelayedCollectionFetch.class ) );
 					} );
@@ -337,9 +337,9 @@ public class EntityGraphLoadPlanBuilderTest implements SessionFactoryScopeAware
 
 		final EntityResult entityResult = (EntityResult) domainResult;
 		assertThat( entityResult.getReferencedModePart().getJavaType().getJavaTypeClass(), assignableTo( expectedEntityJpaClass ) );
-		assertThat( entityResult.getFetches(), hasSize( 1 ) );
+		assertThat( entityResult.getFetches().size(), is( 1 ) );
 
-		final Fetch fetch = entityResult.getFetches().get( 0 );
+		final Fetch fetch = entityResult.getFetches().iterator().next();
 		assertThat( fetch, instanceOf( EntityFetch.class ) );
 
 		final EntityFetch entityFetch = (EntityFetch) fetch;

hibernate-core/src/test/java/org/hibernate/orm/test/entitygraph/ast/HqlEntityGraphTest.java

@@ -191,9 +191,9 @@ public class HqlEntityGraphTest implements SessionFactoryScopeAware {
 						assertThat( companyFetch, notNullValue() );
 
 						final EntityResult companyEntityResult = ( (EntityFetchJoinedImpl) companyFetch).getEntityResult();
-						assertThat( companyEntityResult.getFetches(), hasSize( 1 ) );
+						assertThat( companyEntityResult.getFetches().size(), is( 1 ) );
 
-						final Fetch shipAddressesFetch = companyEntityResult.getFetches().get( 0 );
+						final Fetch shipAddressesFetch = companyEntityResult.getFetches().iterator().next();
 						assertThat( shipAddressesFetch.getFetchedMapping().getPartName(), is( "shipAddresses" ) );
 						assertThat( shipAddressesFetch, instanceOf( DelayedCollectionFetch.class ) );
 					} );
@@ -345,9 +345,9 @@ public class HqlEntityGraphTest implements SessionFactoryScopeAware {
 
 		final EntityResult entityResult = (EntityResult) domainResult;
 		assertThat( entityResult.getReferencedModePart().getJavaType().getJavaTypeClass(), assignableTo( expectedEntityJpaClass ) );
-		assertThat( entityResult.getFetches(), hasSize( 1 ) );
+		assertThat( entityResult.getFetches().size(), is( 1 ) );
 
-		final Fetch fetch = entityResult.getFetches().get( 0 );
+		final Fetch fetch = entityResult.getFetches().iterator().next();
 		assertThat( fetch, instanceOf( EntityFetch.class ) );
 
 		final EntityFetch entityFetch = (EntityFetch) fetch;

hibernate-core/src/test/java/org/hibernate/orm/test/entitygraph/ast/LoadPlanBuilderTest.java

@@ -73,12 +73,12 @@ public class LoadPlanBuilderTest {
 		final EntityResult entityResult = (EntityResult) domainResult;
 		assertThat( entityResult.getFetches() ).hasSize( 2 );
 
-		final Fetch txtFetch = entityResult.getFetches().get( 0 );
+		final Fetch txtFetch = entityResult.getFetches().get( entityDescriptor.findAttributeMapping( "msgTxt" ) );
 		assertThat( txtFetch ).isNotNull();
 		assertThat( txtFetch.getFetchedMapping().getFetchableName() ).isEqualTo( "msgTxt" );
 		assertThat( txtFetch.getTiming() ).isEqualTo( FetchTiming.IMMEDIATE );
 
-		final Fetch posterFetch = entityResult.getFetches().get( 1 );
+		final Fetch posterFetch = entityResult.getFetches().get( entityDescriptor.findAttributeMapping( "poster" ) );
 		assertThat( posterFetch ).isNotNull();
 		assertThat( posterFetch.getFetchedMapping().getFetchableName() ).isEqualTo( "poster" );
 		assertThat( posterFetch.getTiming() ).isEqualTo( FetchTiming.DELAYED );
@@ -114,12 +114,12 @@ public class LoadPlanBuilderTest {
 		final EntityResult entityResult = (EntityResult) domainResult;
 		assertThat( entityResult.getFetches() ).hasSize( 2 );
 
-		final Fetch txtFetch = entityResult.getFetches().get( 0 );
+		final Fetch txtFetch = entityResult.getFetches().get( entityDescriptor.findAttributeMapping( "msgTxt" ) );
 		assertThat( txtFetch ).isNotNull();
 		assertThat( txtFetch.getFetchedMapping().getFetchableName() ).isEqualTo( "msgTxt" );
 		assertThat( txtFetch.getTiming() ).isEqualTo( FetchTiming.IMMEDIATE );
 
-		final Fetch posterFetch = entityResult.getFetches().get( 1 );
+		final Fetch posterFetch = entityResult.getFetches().get( entityDescriptor.findAttributeMapping( "poster" ) );
 		assertThat( posterFetch ).isNotNull();
 		assertThat( posterFetch.getFetchedMapping().getFetchableName() ).isEqualTo( "poster" );
 		assertThat( posterFetch.getTiming() ).isEqualTo( FetchTiming.IMMEDIATE );

hibernate-core/src/test/java/org/hibernate/orm/test/loading/MappedFetchTests.java

@@ -36,6 +36,7 @@ import org.hibernate.sql.results.graph.collection.internal.EagerCollectionFetch;
 import org.hibernate.sql.results.graph.DomainResult;
 import org.hibernate.sql.results.graph.entity.EntityResult;
 import org.hibernate.sql.results.graph.Fetch;
+import org.hibernate.sql.results.graph.internal.ImmutableFetchList;
 
 import org.hibernate.testing.orm.junit.DomainModel;
 import org.hibernate.testing.orm.junit.SessionFactory;
@@ -85,22 +86,22 @@ public class MappedFetchTests {
 		assertThat( domainResult, instanceOf( EntityResult.class ) );
 
 		final EntityResult entityResult = (EntityResult) domainResult;
-		final List<Fetch> fetches = entityResult.getFetches();
+		final ImmutableFetchList fetches = entityResult.getFetches();
 
 		// name + both lists
 		assertThat( fetches.size(), is( 3 ) );
 
 		// order is alphabetical...
 
-		final Fetch nameFetch = fetches.get( 0 );
+		final Fetch nameFetch = fetches.get( rootEntityDescriptor.findAttributeMapping( "name" ) );
 		assertThat( nameFetch.getFetchedMapping().getFetchableName(), is( "name" ) );
 		assertThat( nameFetch, instanceOf( BasicFetch.class ) );
 
-		final Fetch nickNamesFetch = fetches.get( 1 );
+		final Fetch nickNamesFetch = fetches.get( rootEntityDescriptor.findAttributeMapping( "nickNames" ) );
 		assertThat( nickNamesFetch.getFetchedMapping().getFetchableName(), is( "nickNames" ) );
 		assertThat( nickNamesFetch, instanceOf( EagerCollectionFetch.class ) );
 
-		final Fetch simpleEntitiesFetch = fetches.get( 2 );
+		final Fetch simpleEntitiesFetch = fetches.get( rootEntityDescriptor.findAttributeMapping( "simpleEntities" ) );
 		assertThat( simpleEntitiesFetch.getFetchedMapping().getFetchableName(), is( "simpleEntities" ) );
 		assertThat( simpleEntitiesFetch, instanceOf( DelayedCollectionFetch.class ) );