Re: [hibernate-dev] HHH-10478 : OperationContext

Replying for consideration for 6.0. On Mon, Feb 8, 2016 at 6:12 AM, Steve Ebersole <steve(a)hibernate.org&gt; wrote: > This is going to have to wait post-5.1 as I mentioned earlier if this was > not ready prior to last week. > > I have just too much on my plate to look at this over 2 days. > > On Mon, Feb 8, 2016 at 12:29 AM Gail Badner <gbadner(a)redhat.com&gt; wrote: > >> The POC [1] assumes that we only need a single OperationContext for each >> type of operation. OperationContextManager has a Map of OperationContext >> by >> OperationContextType. Each OperationContext object is lazily created on >> the >> first occurence of the corresponding type of operation. >> >> Currently, when an operation is initiated (e.g., by Session.merge( entity >> )), OperationContextManager [2] does the following: >> - calls ManageableOperationContext#beforeOperation, which puts the >> OperationContext "in progress"; >> - executes the operation, which performs cascades according to mappings; >> - calls ManageableOperationContext#afterOperation, which puts the >> OperationContext in an invalid state that is "not in progress". >> >> When an operation cascades to other entities, the same OperationContext >> is >> used. >> >> Obviously, OperationContextManager needs to know if an operation is >> "top-level" (meaning that the operation is on the original entity, and >> not >> cascaded). In the POC, if the relevant OperationContext is not in >> progress >> at the time that an opeation is initiated, then OperationContextManager >> assumes that the operation is top-level. If the OperationContext is "in >> progress", then OperationContextManager assumes that this is a cascaded >> operation. >> >> I am not sure this is always correct. Can anyone think of a case where >> this >> could break down? >> >> In the POC, the following EventSource methods that contain an argument >> for >> the operation cache has been deprecated and is no longer used because the >> contents of that argument has been moved into an OperationContext: >> >> public void merge(String entityName, Object object, Map copiedAlready) >> public void persist(String entityName, Object object, Map createdAlready) >> public void persistOnFlush(String entityName, Object object, Map >> copiedAlready) >> public void refresh(String entityName, Object object, Map >> refreshedAlready) >> public void delete(String entityName, Object child, boolean >> isCascadeDeleteEnabled, Set transientEntities) >> >> Before the POC, it was the above methods that indicated that it was not >> top-level. If it turns out that having a single OperationContext is not >> valid, then there needs to be some other way to determine if the >> operation >> was top-level. >> >> I had originally planned to use PersistenceContext#getCascadeLevel == 0 >> to >> indicate an operation was at the top-level, but I found that won't work >> for >> some operations. For example, the cascade level for a top-level delete >> can >> be > 1 when deleting orphans due to merge or save-or-update operations. >> Another example is that cascade level is not 0 on top-level >> save-or-update >> while flushing. >> >> I have some ideas to work around this, but I didn't want to get too far >> down that path if it wasn't an issue. >> >> Thanks, >> Gail >> >> [1] >> >> https://github.com/gbadner/hibernate-core/blob/3d0e2378cb998788b3205afb1e... >> [2] >> >> https://github.com/gbadner/hibernate-core/blob/3d0e2378cb998788b3205afb1e... >> >> >> On Fri, Feb 5, 2016 at 8:17 PM, Gail Badner <gbadner(a)redhat.com&gt; wrote: >> >> > I've created a gist with an overview of the design: >> > https://gist.github.com/gbadner/f0e635e8fba7b84af233 . I will add a >> new >> > section tomorrow about possible shortcomings. >> > >> > Here is my POC: >> > >> https://github.com/hibernate/hibernate-orm/compare/master...gbadner:HHH-1... >> > . Although no tests fail, the approach may be too simple to model what >> is >> > necessary. >> > >> > At this point the POC is squashed down to 1 commit: >> > >> https://github.com/hibernate/hibernate-orm/commit/3d0e2378cb998788b3205af... >> > >> > Have a look and feel free to comment. >> > >> > Thanks, >> > Gail >> > >> _______________________________________________ >> hibernate-dev mailing list >> hibernate-dev(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/hibernate-dev >> >