[hibernate-dev] Storing values at the session level

[Emmanuel Bernard]

That would be extremely useful. That being said, it's not the only
useful context. On top of the "entity" context, I can see usage for:

- per event context (flush event for example)
- transaction context
- global session context (not sure I have a use case yet but I suspect
  it's useful.

Emmanuel

On Mon 2014-03-10 15:24, Sanne Grinovero wrote:
> This seems like related to the relation-walking optimization we
> discussed for Neo4J: also would need to couple the entity instance to
> the Neo4J document. Currently the Neo4J griddialect would need to run
> a new query for a graph-traversal: not taking advantage of the graph
> capabilities which is of course a problem.
> 
> In Hibernate ORM the EntityEntry stores an array with the loaded
> values from SQL, needed for some of its state handling. I'd say we
> should have a way to store data related to extension points into this
> EntityEntry.
> 
> If we made this as a general purpose enhancement of ORM, we could
> maybe have it abstract the storage of the additional attributes into,
> for example, the enhanced entity class definitions: it would add a
> field directly to the Entity instance for you to store such an object.
> There where some chats about maybe doing such an optimization anyway,
> driven by the performance work.
> 
> Sanne
> 
> On 10 March 2014 12:32, Gunnar Morling <gunnar at hibernate.org> wrote:
> > Minor correction:
> >
> >> Unfortunately there is no getter for the session owner on
> > SessionFactoryImplementor
> >
> > s/SessionFactoryImplementor/SessionImplementor
> >
> > --Gunnar
> >
> >
> >
> >
> > 2014-03-10 12:59 GMT+01:00 Gunnar Morling <gunnar at hibernate.org>:
> >
> >> Hi,
> >>
> >> I'm looking into ways for reducing the number of datastore roundtrips in
> >> OGM [1].
> >>
> >> One idea is to fetch associations embedded within entity documents (e.g.
> >> in MongoDB) when loading such document. We'd "remember" the entity document
> >> and could later on retrieve the association from it without going to the
> >> store a second time.
> >>
> >> The problem is the "remembering" part. There is no session-scoped storage
> >> facility as of today which I could use. I contemplated making OgmSession
> >> deal with this, but I can't access that from persisters etc. Instead I'm
> >> seeing the wrapped SessionImpl (to which OgmSession delegates for many
> >> operations) and I couldn't find a way to reach the wrapping OgmSession
> >> instance.
> >>
> >> Now I noticed the concept of "SessionOwner" in SessionImpl and am
> >> wondering whether I could make use of this. When creating the SessionImpl,
> >> I could pass the OgmSession as owner and have it maintain a session-scoped
> >> storage. Unfortunately there is no getter for the session owner on
> >> SessionFactoryImplementor, though.
> >>
> >> Would it be feasible to add this getter and thus make a session's owner
> >> accessible? Or is there any other (better) way to achieve what I described?
> >>
> >> Many thanks,
> >>
> >> --Gunnar
> >>
> >> [1] https://hibernate.atlassian.net/browse/OGM-469
> >>
> >>
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