[infinispan-dev] Missing Externalizers for the Lucene Query classes

[Gustavo Fernandes]

On Tue, Nov 15, 2016 at 11:48 AM, Sanne Grinovero <sanne at infinispan.org>
wrote:

> On 14 November 2016 at 16:05, Galder Zamarreño <galder at redhat.com> wrote:
> >
> >
> > --
> > Galder Zamarreño
> > Infinispan, Red Hat
> >
> > > On 31 Oct 2016, at 19:52, Sanne Grinovero <sanne at infinispan.org>
> wrote:
> > >
> > > Following up on today's meeting minutes.
> > >
> > > Galder asked if Hibernate Search was going to provide externalizers
> > > for the Lucene Query classes; let me clarify that I don't think that
> > > those belong in the Hibernate Search code base, not least we hope to
> > > avoid ever needing to implement them.
> > >
> > > A soft reason to not have them in Hibernate Search is that this
> > > project never needs to serialise any Query; this is a requirement of
> > > Infinispan Query only, needed to implement Infinispan specific
> > > extensions to the query engine.
> > > Although, these are very nice extensions so I'd not like to see them
> > > dropped: I'd hope that Infinispan could work around the lack of proper
> > > externalizers for the moment, as it has always been able to do so far.
> >
> > ^ We can only workaround it because the external marshaller right now
> relies on JBoss Marshalling, which enables us to plug in at the object
> table level even for Serializable objects and we can lookup externalizers.
> >
> > I know for a fact we can't plug like that if using standard
> serialization, and there's no guarantee that we'll be able to support this
> use case with another marshaller.
> >
> > So, we should really be avoiding such edge cases. I don't mind where the
> externalizers are placed.
>
>
> Hi Galder,
>
> sorry but I don't understand if you're asking us to do something, and
> what is the proposal?
>


As I pointed out before, the short term solution is [1]: we will add an
Externalizer *on Infinispan* for the HSearch
classes that don't have one and are affected by Clustered Queries. This
should remove the edge case altogether and no change is
required on Hibernate Search side


[1] https://issues.jboss.org/browse/ISPN-7156

Thanks,
Gustavo


>
> I'd strongly prefer to keep them as-is for now, and refactor this as
> needed in the near future when we'll change the Clustered Query API
> and take advantage of ICKLE.
>
> Thanks,
> Sanne
>
> >
> >
> > >
> > > A stronger reason is that this would introduce circular dependencies
> > > between the two projects, and a big overhead of release coordination:
> > > we had this in the past, very all very glad this is in the past!
> > >
> > > When we'll have IQL, this will both define a good "on the wire"
> > > representation which would solve the serialization problem, and IQL
> > > will also limit the amount of Query types which we will need to
> > > support, as at that point we will be able to limit the support for
> > > Clustered Queries (which is the feature needing to serialize the
> > > queries) to those which IQL can express, and thus serialize.
> > >
> > > At that point we'll be able to deprecate the the Clustered Query API
> > > which accepts a user instance of the Lucene Query, and only run
> > > clustered queries for queries expressed over IQL. Not least we'll be
> > > able to automatically determine if the query is best run as a
> > > clustered query or as a local query, removing this complexity from the
> > > user's responsibilities.
> > >
> > > In conclusion, we'll still be using the "Clustered Query"
> > > functionality, but not exposing it, and by doing so we won't need any
> > > externalizer. But for now please keep the tests running with the
> > > existing externalizer strategies: we just need to keep it functional,
> > > but there's no need to optimise performance of these externalizers as
> > > we'll get rid of them.
> > >
> > > Thanks,
> > > Sanne
> > > _______________________________________________
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> > > infinispan-dev at lists.jboss.org
> > > https://lists.jboss.org/mailman/listinfo/infinispan-dev
> >
> >
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