Re: [hibernate-dev] [OGM] Behavior of GenerationType.IDENTITY with OGM
2014/1/21 Sanne Grinovero <sanne(a)hibernate.org>
I don't know if that's explicitly defined in the spec, but
even if it
wasn't I wouldn't be happy as a user to see an exception for such a
commonly used feature.
So you prefer to silently use another strategy than the one configured
instead of reporting the issue? Wouldn't rather a user work with AUTO if
she wanted the engine to choose a strategy?
Do you know how ORM handles the case of using IDENTITY on stores which
don't support it?
Clearly when such an ID is requested we need to invoke the server
out of
the batching / transaction context, which might be a suboptimal strategy
but exactly what the user is asking for:theyr choice of they want to
tradeoff simplicity for performance.
I'm not quite following. Using TABLE behavior instead of IDENTITY doesn't
seem like doing what the user has asked for?
Also to keep in mind for the Infinispan case the current approach
is
very slow but now that we've upgraded to latest wildfly there's a new
feature could use to optimise for this: COUNTER protocol in JGroups
combined with FORK channels.
That's interesting, do you have a pointer with more information on that?
Sanne
On 20 Jan 2014 16:42, "Gunnar Morling" <gunnar(a)hibernate.org> wrote:
> Ah, is that specified somewhere? I couldn't find anything in the spec from
> a quick look.
>
>
> 2014/1/20 Emmanuel Bernard <emmanuel(a)hibernate.org>
>
> > The problem is that in JPA, IDENTITY returns a long, not a UUID.
> >
> > On Mon 2014-01-20 12:23, Gunnar Morling wrote:
> > > Hi,
> > >
> > > While reviewing the PR for batch operations in OGM [1], I took some
> time
> > to
> > > better understand OGM's approaches for id generation.
> > >
> > > Now I'm wondering about how GenerationType.IDENTITY is implemented.
> The
> > > corresponding generator (OgmIdentityGenerator) just delegates to a
> > > table-based strategy, so an id is always pre-allocated and then passed
> > into
> > > the dialect when creating a tuple.
> > >
> > > I think it would be nice to have proper support for server-generated
> ids,
> > > in particular since some stores return the inserted id directly from
> the
> > > insert operation, i.e. without requiring another read.
> > >
> > > For the time being, as the current implementation doesn't really
> adhere
> > to
> > > the semantics of GenerationType.IDENTITY, should we raise an error
> when
> > > using it instead of silently using another strategy?
> > >
> > > Thoughts?
> > >
> > > --Gunnar
> > >
> > > [1] https://hibernate.atlassian.net/browse/OGM-175
> > > _______________________________________________
> > > hibernate-dev mailing list
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> >
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