[infinispan-dev] XA transactions on a single CacheManager?

[Sanne Grinovero]

On 21 March 2016 at 12:18, Pedro Ruivo <pedro at infinispan.org> wrote:
>
>
> On 03/21/2016 11:19 AM, Sanne Grinovero wrote:
>> On 21 March 2016 at 10:07, Pedro Ruivo <pedro at infinispan.org> wrote:
>>> Hi Sanne
>>>
>>> On 03/15/2016 07:22 PM, Sanne Grinovero wrote:
>>>> Hi all,
>>>>
>>>> I just noticed that when I'm making changes to multiple caches within
>>>> the same transaction, the transaction manager will treat this as XA
>>>> transactions.
>>>>
>>>> That seems suboptimal as they are all managed by the same resource; is
>>>> there a configuration I'm missing or should I open a JIRA to ask for
>>>> an improvement?
>>>
>>> what are you suggesting? Having a single XA resource per cache manager
>>> instead of one per cache?
>>
>> Yes, I actually expected that to be the case already.
>> Would that be complex? I am not familiar at all with this code, I was
>> just surprised as I don't see why it is the way it is: I don't need XA
>> transactions when writing to multiple tables on a same RDBMs ;)
>>
>> My guess is that we originally thought of Caches a being used mostly
>> independently, but I think experience is telling us differently.
>
> It makes sense since the tables in RDBMs has some kind of relation
> between them. Caches on other hand, they haven't.

That statement is too broad, and proven wrong with real world examples
and practical requirements from our users; in my experience it also is
the primary reason to enable transactions at all.

I'd rather question why this wasn't done than question which use cases
are appropriate, as I don't see what benefit it brings to consider
each cache a different resource? Am  I missing a trade-off or is it
fair to say that there are no drawbacks in improving this?


> It will not be impossible to move the XA to the cache manager, although,
> it would add some complexity to our xa implementation. Randim already
> opened a JIRA.
>
> It would be good to know if someone has any issue with the
> per-cache-manager xa :)
>
>>
>>>> I'm not just asking for performance reasons: having to setup a
>>>> transaction manager is an annoying configuration step for Java SE
>>>> users.
>>>
>>> I got a little confused by this. You can use the same transaction
>>> manager in all the caches, so you have to configured it once.
>>> If you don't have one, you could use the DummyTransactionManager (we
>>> need to rename it!) in the core that contains the basic to handle
>>> transactions.
>>
>> To support XA transactions the transaction manager requires both a
>> different configuration
>> and different dependencies.
>>
>> I noticed while working on a "Getting started with Hibernate OGM"
>> which needs to be simple of course,
>> and this example happens to use Infinispan.
>> Since we need writes on multiple caches, this makes the setup phase of
>> the tutorial much harder, to the point that I'm considering to simply
>> switch to something like MongoDB so that I can keep the OGM tutorial
>> focused.
>
> Even if you have a per-cache-manager xa, you still have to configure the
> TransactionManager.
>
> If you don't want to complicate the "getting start" you could use the
> DummyTransactionManager to achieve the same result. In infinispan, you
> only need to set the "transaction-manager-lookup" in <transaction> tag
> to fetch the DummyTransactionManager.

it might just be an example, but that doesn't look good enough.

Thanks,
Sanne


>
>>
>>>
>>> Cheers,
>>> Pedro
>>>
>>>>
>>>> Thanks,
>>>> Sanne
>>>> _______________________________________________
>>>> infinispan-dev mailing list
>>>> infinispan-dev at lists.jboss.org
>>>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
>>>>
>>> _______________________________________________
>>> infinispan-dev mailing list
>>> infinispan-dev at lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
>> _______________________________________________
>> infinispan-dev mailing list
>> infinispan-dev at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
>>
> _______________________________________________
> infinispan-dev mailing list
> infinispan-dev at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/infinispan-dev