Message Title

One of the most significant areas of concern surrounds the techniques used to handle bytecode enhanced entities; the agent reports the following:

1:	io.quarkus.benchmark.model.World
Count:	51703308
Types:
	org.hibernate.engine.spi.PersistentAttributeInterceptable
	org.hibernate.engine.spi.ManagedEntity
	org.hibernate.engine.spi.SelfDirtinessTracker
	org.hibernate.engine.spi.Managed
Traces:
	org.hibernate.engine.internal.EntityEntryContext.getAssociatedManagedEntity(EntityEntryContext.java:153)
		class: org.hibernate.engine.spi.ManagedEntity
		count: 12108604
	org.hibernate.engine.internal.EntityEntryContext.getAssociatedManagedEntity(EntityEntryContext.java:154)
		class: org.hibernate.engine.spi.ManagedEntity
		count: 6511885
	org.hibernate.property.access.spi.EnhancedSetterImpl.set(EnhancedSetterImpl.java:49)
		class: org.hibernate.engine.spi.PersistentAttributeInterceptable
		count: 4770509
	org.hibernate.tuple.entity.PojoEntityTuplizer.afterInitialize(PojoEntityTuplizer.java:227)
		class: org.hibernate.engine.spi.SelfDirtinessTracker
		count: 4762608
	org.hibernate.tuple.entity.PojoEntityTuplizer.afterInitialize(PojoEntityTuplizer.java:210)
		class: org.hibernate.engine.spi.PersistentAttributeInterceptable
		count: 3617911
	org.hibernate.tuple.entity.PojoEntityTuplizer.afterInitialize(PojoEntityTuplizer.java:228)
		class: org.hibernate.engine.spi.SelfDirtinessTracker
		count: 3325834
	org.hibernate.tuple.entity.BytecodeEnhancementMetadataPojoImpl.extractLazyInterceptor(BytecodeEnhancementMetadataPojoImpl.java:271)
		class: org.hibernate.engine.spi.PersistentAttributeInterceptable
		count: 2883597
	org.hibernate.tuple.entity.PojoEntityInstantiator.applyInterception(PojoEntityInstantiator.java:55)
		class: org.hibernate.engine.spi.PersistentAttributeInterceptable
		count: 2740804
	org.hibernate.engine.internal.StatefulPersistenceContext.clear(StatefulPersistenceContext.java:236)
		class: org.hibernate.engine.spi.PersistentAttributeInterceptable
		count: 2617366
	org.hibernate.property.access.spi.EnhancedSetterImpl.set(EnhancedSetterImpl.java:50)
		class: org.hibernate.engine.spi.PersistentAttributeInterceptable
		count: 2560881
	org.hibernate.tuple.entity.AbstractEntityTuplizer.linkToSession(AbstractEntityTuplizer.java:717)
		class: org.hibernate.engine.spi.PersistentAttributeInterceptable
		count: 1705389
	org.hibernate.engine.internal.StatefulPersistenceContext.clear(StatefulPersistenceContext.java:237)
		class: org.hibernate.engine.spi.PersistentAttributeInterceptable
		count: 1464702
	org.hibernate.engine.internal.EntityEntryContext.addEntityEntry(EntityEntryContext.java:94)
		class: org.hibernate.engine.spi.ManagedEntity
		count: 1391146
	org.hibernate.engine.internal.EntityEntryContext.addEntityEntry(EntityEntryContext.java:96)
		class: org.hibernate.engine.spi.ManagedEntity
		count: 1242069
	org.hibernate.property.access.internal.PropertyAccessStrategyResolverStandardImpl.resolvePropertyAccessStrategy(PropertyAccessStrategyResolverStandardImpl.java:40)
		class: org.hibernate.engine.spi.Managed
		count: 2
	org.hibernate.tuple.entity.PojoEntityInstantiator.<init>(PojoEntityInstantiator.java:38)
		class: org.hibernate.engine.spi.PersistentAttributeInterceptable
		count: 1
--------------------------

Source code matches Hibernate ORM version 5.6.12.Final - and while the agent is prone to reporting false positives, we believe this is not the case.

This issue has - surprisingly - eluded performance diagnostic tools so far, and yet has very significant impact on performance; scalability is particularly affected as an high number of cache to cache communication is triggered, including via false sharing of the type cache information.

I believe we can, at least partially, mitigage the performance hit via a minor refactoring which could be applied to both ORM 5.6 and 6+; a better and more thourough analysis will follow separately but will not be backported to older ORM versions.