[infinispan-dev] Integration between HotRod and OGM

Wed Jan 22 08:58:06 EST 2014

On Tue, Jan 21, 2014 at 4:07 PM, Mircea Markus <mmarkus at redhat.com> wrote:

> Hi Emmanuel,
>
> Just had a good chat with Davide on this and one solution to overcome the
> shortcoming you mentioned in the above email would be to enhance the hotrod
> client to support grouping:
>
> RemoteClient.put(G g, K k, V v); //first param is the group
> RemoteClinet.getGroup(G g) : Map<K,V>;
>

I think you'd also need RemoteClient.get(G g, K k), as in embedded mode the
group is included in the key.

>
> It requires an enhancement on our local grouping API:
> EmbeddedCache.getGroup(G). This is something useful for us in a broader
> context, as it is the step needed to be able to deprecated AtomicMaps and
> get suggest them being replaced with Grouping.
>

It would also require us to keep a Set<K> for each group, with the keys
associated with that group. As such, I'm not sure it would be a lot easier
to implement (correctly) than FineGrainedAtomicMap.

> This approach still has some limitations compared to the current embedded
> integration:
> - performance caused by the lack of transactions: this means increased TCP
> chattiness between the Hot Rod client and the server.
> - you'd have to handle atomicity, potentially by retrying an operation
>
> What do you think?
>
>
> On Dec 3, 2013, at 3:10 AM, Mircea Markus <mmarkus at redhat.com> wrote:
>
> >
> > On Nov 19, 2013, at 10:22 AM, Emmanuel Bernard <emmanuel at hibernate.org>
> wrote:
> >
> >> It's an interesting approach that would work fine-ish for entities
> >> assuming the Hot Rod client is multi threaded and assuming the client
> >> uses Future to parallelize the calls.
> >
> > The Java Hotrod client is both multithreaded and exposes an Async API.
> >
> >>
> >> But it won't work for associations as we have them designed today.
> >> Each association - or more precisely the query results to go from an
> >> entity A1 to the list of entities B associated to it - is represented by
> >> an AtomicMap.
> >> Each entry in this map does correspond to an entry in the association.
> >>
> >> While we can "guess" the column names and build from the metadata the
> >> list of composed keys for entities, we cannot do the same for
> >> associations as the key is literally the (composite) id of the
> >> association and we cannot guess that most of the time (we can in very
> >> pathological cases).
> >> We could imagine that we list the association row keys in a special
> >> entry to work around that but this approach is just as problematic and
> >> is conceptually the same.
> >> The only solution would be to lock the whole association for each
> >> operation and I guess impose some versioning / optimistic lock.
> >>
> >> That is not a pattern that scales sufficiently from my experience.
> >
> > I think so too :-)
> >
> >> That's the problem with interconnected data :)
> >>
> >> Emmanuel
> >>
> >> On Mon 2013-11-18 23:05, Mircea Markus wrote:
> >>> Neither the grouping API nor the AtomicMap work over hotrod.
> >>> Between the grouping API and AtomicMap, I think the one that would
> make more sense migrating is the grouping API.
> >>> One way or the other, I think the hotrod protocol would require an
> enhancement - mind raising a JIRA for that?
> >>> For now I guess you can sacrifice performance and always sending the
> entire object across on every update instead of only the deltas?
> >>>
> >>> On Nov 18, 2013, at 9:56 AM, Emmanuel Bernard <emmanuel at hibernate.org>
> wrote:
> >>>
> >>>> Someone mentioned the grouping API as some sort of alternative to
> >>>> AtomicMap. Maybe we should use that?
> >>>> Note that if we don't have a fine-grained approach we will need to
> >>>> make sure we *copy* the complex data structure upon reads to mimic
> >>>> proper transaction isolation.
> >>>>
> >>>> On Tue 2013-11-12 15:14, Sanne Grinovero wrote:
> >>>>> On 12 November 2013 14:54, Emmanuel Bernard <emmanuel at hibernate.org>
> wrote:
> >>>>>> On the transaction side, we can start without them.
> >>>>>
> >>>>> +1 on omitting transactions for now.
> >>>>>
> >>>>> And on the missing AtomicMaps, I hope the Infinispan will want to
> implement it?
> >>>>> Would be good to eventually converge on similar featuresets on remote
> >>>>> vs embedded APIs.
> >>>>>
> >>>>> I know the embedded version relies on batching/transactions, but I
> >>>>> guess we could obtain a similar effect with some ad-hoc commands in
> >>>>> Hot Rod?
> >>>>>
> >>>>> Sanne
> >>>>>
> >>>>>>
> >>>>>> On Tue 2013-11-12 14:34, Davide D'Alto wrote:
> >>>>>>> Hi,
> >>>>>>> I'm working on the integration between HotRod and OGM.
> >>>>>>>
> >>>>>>> We already have a dialect for Inifinispan and I'm trying to follow
> the same
> >>>>>>> logic.
> >>>>>>> At the moment I'm having two problems:
> >>>>>>>
> >>>>>>> 1) In the Infinispan dialect we are using the AtomicMap and the
> >>>>>>> AtomicMapLookup but this classes don't work with the RemoteCache.
> Is there
> >>>>>>> an equivalent for HotRod?
> >>>>>>>
> >>>>>>> 2) As far as I know HotRod does not support transactions. I've
> found a link
> >>>>>>> to a branch on Mircea repository:
> >>>>>>> https://github.com/mmarkus/ops_over_hotrod/wiki/Usage-guide
> >>>>>>> Is this something I could/should use?
> >>>>>>>
> >>>>>>> Any help is appreciated.
> >>>>>>>
> >>>>>>> Thanks,
> >>>>>>> Davide
> >>>>>>
> >>>>>>> _______________________________________________
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> >>>>>>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
> >>>>>>
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> >>>
> >>> Cheers,
> >>> --
> >>> Mircea Markus
> >>> Infinispan lead (www.infinispan.org)
> >>>
> >>>
> >>>
> >>>
> >>>
> >>> _______________________________________________
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> >
> > Cheers,
> > --
> > Mircea Markus
> > Infinispan lead (www.infinispan.org)
> >
> >
> >
> >
>
> Cheers,
> --
> Mircea Markus
> Infinispan lead (www.infinispan.org)
>
>
>
>
>
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