I don't know that we're going to agree here, but I *do* strongly disagree.
They're independent libraries, and people use each exclusively of the
other. There mustn't be cross-dependencies.
And I have to admit, I don't understand what the problem is. I simply use
a different naming convention for each Cluster Region, and that's no more
work than choosing a different prefix. What's the big deal?
On Thu, Feb 9, 2017 at 12:47 PM, Qing Zheng <qzhen...@gmail.com> wrote:
> I disagree, you have all the pieces of your system, however, they are not
> fit well with each other at least that's how I feel from a user point of
> view. Just like you have database tableA and tableB, the ID in tableA has
> nothing to do with ID in tableB. This may not be a good analogy, but you
> get the idea. I agree with you at the lower level of akka persistence
> (journal/snapshot) it should have no knowledge of sharding at all.However,
> in the akka persistence base actor class it should take care of this.
> Otherwise every user has to come up with its own scheme to make persistence
> id unique across all actor classes. It would be nice to provide a default
> implementation in the base class and a user can customize it. The default
> implementation can simply encode the actor class info together with some
> unique instance id within that class.
>
> Thanks
> Qing
>
> On Thursday, February 9, 2017 at 5:42:25 AM UTC-8, Justin du coeur wrote:
>>
>> Persistence and sharding are separate systems -- while they work well
>> together, neither depends upon the other. So it would be inappropriate for
>> persistence to depend on knowledge of which sharding region an Actor is
>> in...
>>
>> On Wed, Feb 8, 2017 at 11:54 AM, Qing Zheng <qzhe...@gmail.com> wrote:
>>
>>> Hi Patrik,
>>>
>>> My fault, I do have one instance of ActorA that has a duplicate
>>> persistence id as another instance of ActorB. Sorry about that.
>>>
>>> Without persistence, the only requirement is entity id should be
>>> unique within each shard region, with persistence the requirement is
>>> persistence id should be unique across all the shard regions. My question
>>> is would it better to keep the same programming model with/without
>>> persistence? What's the reason not just to have persistence id only unique
>>> within the context of a shard region?
>>>
>>> Thanks
>>> Qing
>>>
>>> On Tuesday, February 7, 2017 at 9:00:26 AM UTC-8, Patrik Nordwall wrote:
>>>>
>>>> I don't know without seeing more code.
>>>>
>>>> On Tue, Feb 7, 2017 at 5:57 PM, Qing Zheng <qzhe...@gmail.com> wrote:
>>>>
>>>>> Yes, the persistence IDs are unique for each persistence instance.
>>>>> Anything else you think I am missing?
>>>>>
>>>>> Thanks for the quick response.
>>>>>
>>>>> Qing
>>>>>
>>>>> On Tuesday, February 7, 2017 at 1:26:45 AM UTC-8, Patrik Nordwall
>>>>> wrote:
>>>>>>
>>>>>> How have you defined the persistenceId in ActorA and ActorB? It must
>>>>>> be unique for each persistent actor instance.
>>>>>>
>>>>>> On Tue, Feb 7, 2017 at 8:39 AM, Qing Zheng <qzhe...@gmail.com> wrote:
>>>>>>
>>>>>>> Hi,
>>>>>>>
>>>>>>> I have two actor types
>>>>>>>
>>>>>>>
>>>>>>> class ActorA extends UntypedPersistentActor {
>>>>>>> //....
>>>>>>> }
>>>>>>>
>>>>>>>
>>>>>>> class ActorB extends UntypedPersistentActor {
>>>>>>> //....
>>>>>>> }
>>>>>>>
>>>>>>> public static void main(String[] argv) {
>>>>>>> ActorSystem system = ActorSystem.create("ActorSystem",
>>>>>>> ConfigFactory.load(argv[0]));
>>>>>>> Persistence.apply(system);
>>>>>>> ClusterShardingSettings settings = ClusterShardingSettings.create
>>>>>>> (system);
>>>>>>> ClusterExtractor extractor = new ClusterExtractor();
>>>>>>>
>>>>>>> ClusterSharding.get(system).start("ShardRegionA",
>>>>>>> Props.create(ActorA.class), settings, extractor);
>>>>>>> ClusterSharding.get(system).start("ShardRegionB",
>>>>>>> Props.create(ActorB.class), settings, extractor);
>>>>>>>
>>>>>>> ActorRef shardRegionA = ClusterSharding.get(system).sh
>>>>>>> ardRegion("ShardRegionA");
>>>>>>> ActorRef shardRegionB = ClusterSharding.get(system).sh
>>>>>>> ardRegion("ShardRegionB");
>>>>>>>
>>>>>>> //.....
>>>>>>>
>>>>>>> Without calling persist.add method everything works as I expected.
>>>>>>> I can send a cluster message to shard region A or B and ActorA or ActorB
>>>>>>> will handle the corresponding message differently.However, after
>>>>>>> invoking
>>>>>>> the persist.add method. ActorA will receive recovery message for ActorB
>>>>>>> or
>>>>>>> maybe vice versa. Looks like the cluster messages that have been
>>>>>>> persisted
>>>>>>> do not have the shard region information. How can I solve this problem?
>>>>>>>
>>>>>>> Thanks
>>>>>>> Qing
>>>>>>>
>>>>>>> --
>>>>>>> >>>>>>>>>> Read the docs: http://akka.io/docs/
>>>>>>> >>>>>>>>>> Check the FAQ: http://doc.akka.io/docs/akka/c
>>>>>>> urrent/additional/faq.html
>>>>>>> >>>>>>>>>> Search the archives: https://groups.google.com/grou
>>>>>>> p/akka-user
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>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>>
>>>>>> Patrik Nordwall
>>>>>> Akka Tech Lead
>>>>>> Lightbend <http://www.lightbend.com/> - Reactive apps on the JVM
>>>>>> Twitter: @patriknw
>>>>>>
>>>>>> --
>>>>> >>>>>>>>>> Read the docs: http://akka.io/docs/
>>>>> >>>>>>>>>> Check the FAQ: http://doc.akka.io/docs/akka/c
>>>>> urrent/additional/faq.html
>>>>> >>>>>>>>>> Search the archives: https://groups.google.com/grou
>>>>> p/akka-user
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>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>>
>>>> Patrik Nordwall
>>>> Akka Tech Lead
>>>> Lightbend <http://www.lightbend.com/> - Reactive apps on the JVM
>>>> Twitter: @patriknw
>>>>
>>>> --
>>> >>>>>>>>>> Read the docs: http://akka.io/docs/
>>> >>>>>>>>>> Check the FAQ: http://doc.akka.io/docs/akka/c
>>> urrent/additional/faq.html
>>> >>>>>>>>>> Search the archives: https://groups.google.com/grou
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>>
>> --
> >>>>>>>>>> Read the docs: http://akka.io/docs/
> >>>>>>>>>> Check the FAQ: http://doc.akka.io/docs/akka/
> current/additional/faq.html
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>>>>>>>>>> Read the docs: http://akka.io/docs/
>>>>>>>>>> Check the FAQ:
>>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html
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