Actually I'd like regular users to be able to define their own
RebalancePolicies and ConsistentHashFactories, without modifying
ClusterTopologyManagerImpl/ClusterCacheStatus, so I see this as a good
opportunity to modify our implementation to allow it.
On Tue, Feb 12, 2013 at 6:04 PM, Pedro Ruivo <pruivo(a)gsd.inesc-id.pt> wrote:
**
Can I modify the existing one?
I'm thinking in the following:
ClusterTopologyManagerImpl.handleNewMappings(...) { //new method
ClusterCacheStatus status = //get status for cache name
status.setNewMappings(...) //synchronized of course
rebalancePolicy.updateCacheStatus(...);
}
Like I said, I'd like to keep ClusterTopologyManager as generic as possible
wrt rebalance strategies, so I think your DataPlacementManager should call
your custom RebalancePolicy directly.
The rebalance policy could keep the new mappings in a map on its own,
although maybe it would be a nice touch to allow storing custom state in
ClusterCacheStatus.
DefaultRebalancePolicy.updateCacheStatus(...) { //modified
...
if (!status.hasJoiners() && isBalanced(...) &&
!status.hasNewMappings())
{ //added last condition
return;
}
...
}
I guess you'd also need to clean up the old "new mappings" here after the
rebalance is done.
ClusterTopologyManagerImpl.startRebalance(...) { //modifed
...
chFactory.rebalance(ch);
chFactory.applyMappings(ch, status.getNewMappings()); //added.
... //if it is the same ch, no state transfer is triggered
}
This would require ClusterTopologyManagerImpl to know about your custom
ConsistentHashFactory, and it wouldn't work with another
ConsistentHashFactory that requires different custom data. So I'd rather we
add a generic parameter to ConsistentHashFactory.rebalance.
What do you think?
Thanks,
Pedro
On 2/12/13 3:39 PM, Dan Berindei wrote:
Sorry, I didn't read your code so I just assumed you're writing your own
RebalancePolicy.
I think you need to implement your own RebalancePolicy, because
ClusterTopologyManagerImpl by itself doesn't remember that a rebalance was
triggerred. So if you call startRebalance, but there is already a rebalance
in progress, it is just ignored. When the in-progress rebalance finishes,
it calls RebalancePolicy.updateCacheStatus, and it's the RebalancePolicy
implementation's job to start a new rebalance if needed.
On Tue, Feb 12, 2013 at 5:28 PM, Pedro Ruivo <pruivo(a)gsd.inesc-id.pt>wrote:
> Hi Dan,
>
>
> On 2/12/13 3:12 PM, Dan Berindei wrote:
>
> Hi Pedro
>
> When I split off the RebalancePolicy I was thinking that when a
> RebalancePolicy needs to collaborate with a ConsistentHashFactory, they
> should do so via another cache manager-scoped component. But that doesn't
> really work (yet?), because ConsistentHashFactory can't access any
> components.
>
> I didn't understand the previous sentence... Do I need to invoke
> anything in the RebalancePolicy?
>
> So far, I'm invoking directly in the ClusterTopologyManager:
>
https://github.com/pruivo/infinispan/blob/cloudtm_v2/core/src/main/java/o...
>
> Thanks!
>
> Cheers,
> Pedro
>
>
> I think it would be better to extend
> ClusterTopologyManager.triggerRebalance (and
> ConsistentHashFactory.rebalance) to accept an arbitrary Object parameter.
> Then RebalancePolicy could use this parameter to pass extra information to
> the CHF, like your Mappings object, and then when
> ClusterTopologyManagerImpl asks for a balanced CH, the CHF will include the
> Mappings in the result CH. What do you think?
>
> In order to trigger the rebalance you have to call startRebalance, and
> the new ("balanced") consistent hash must not be equal to the existing
> consistent hash. See
>
https://github.com/infinispan/infinispan/blob/master/core/src/main/java/o...
>
> Cheers
> Dan
>
>
>
>
> On Thu, Feb 7, 2013 at 10:05 PM, Pedro Ruivo <pruivo(a)gsd.inesc-id.pt>wrote:
>
>> Hi,
>>
>> I'm working in a way to rebase auto-placer on top of NBST and I have one
>> question...
>> If you have already forgot, auto-placer analyzes the workload and tries
>> to move the most remote accessed keys to the corresponding requester.
>>
>> After calculating the new mappings, I want to trigger the NBST with this
>> mapping. I'm thinking to add a new method in the ClusterTopologyManager,
>> something like:
>>
>> triggerAutoPlacer(String cacheName, Mappings newMappings);
>>
>> and this method it will be a duplicate of triggerRebalance but instead
>> of doing chFactory.rebalance(CH) (in the startRebalance() method) I'm
>> thinking to do chFactory.autoPlacer(CH, Mappings). The last method will
>> override the defautl CH location.
>>
>> Question: will this solution trigger the NBST or do I have to create the
>> triggerAutoPlacer() method in another class?
>>
>> ps. forget the methods names... I will think in better names later
>>
>> Thanks!!
>>
>> Cheers,
>> Pedro
>> _______________________________________________
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>> infinispan-dev(a)lists.jboss.org
>>
https://lists.jboss.org/mailman/listinfo/infinispan-dev
>>
>
>
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