[infinispan-dev] Integration between HotRod and OGM

[Mircea Markus]

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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>> 
>> Cheers,
>> -- 
>> Mircea Markus
>> Infinispan lead (www.infinispan.org)
>> 
>> 
>> 
>> 
>> 
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Cheers,
-- 
Mircea Markus
Infinispan lead (www.infinispan.org)