[infinispan-dev] Management of shared caches

Mircea Markus mircea.markus at jboss.com
Thu Dec 17 07:22:38 EST 2009 

On Dec 16, 2009, at 1:42 PM, Manik Surtani wrote:

> 
> On 16 Dec 2009, at 11:40, Mircea Markus wrote:
> 
>> 
>> On Dec 16, 2009, at 11:11 AM, Manik Surtani wrote:
>> 
>>> 
>>> On 15 Dec 2009, at 20:16, Brian Stansberry wrote:
>>> 
>>>> On 12/14/2009 01:12 PM, Mircea Markus wrote:
>>>>> yep, that's a good point indeed.
>>>>> Is there any other thing than reference counting that this release method would do?
>>>> 
>>>> The only other thing the AS impl of the JBC CacheManager[1] releaseCache 
>>>> does is deregistration from JMX. But I believe that's already handled in 
>>>> Infinispan.
>>>> 
>>>> OT, there are a couple other things [1] does:
>>>> 
>>>> 1) Supports aliasing of configuratio names; I just created 
>>>> https://jira.jboss.org/jira/browse/ISPN-316 for that.
>>> 
>>> Yes, nice one - there will be some API impact though, how would one submit an alias map?  I wouldn't want injection to be the only path here.
>> Coherence supports regexp for defining cache names. I guess that would also solve ISPN-316, be a more generic solution and also allow better migration from coherence. This won't work for runtime aliasing, not sure we'll be able to do this as well.
> 
> Regexps != aliases, although we could support both.
At least for statically configured aliases (Brian, is that your scenario?) regexp cache names include the alias functionally.
E.g. name="someName | theAlias | otherAlias" is a regexp that accommodates aliasing (and more).
> 
>>> 
>>>> 2) Lets you configure a list of caches to start when the manager starts. 
>>>> Idea was you deployed the cache at server start and took the startup 
>>>> time hit from the JGroups channel discovery then. If you redeploy the 
>>>> service using the cache (e.g. a webapp) the cache stays deployed so you 
>>>> don't need to take the discovery hit again.  AFAIK hasn't actually been 
>>>> used.
>>> 
>>> Hm, each Cache shares the same Transport which is bound to the CacheManager.  So even if Caches start/stop, they won't incur the cost of rediscovery.  E.g.:
>>> 
>>> CacheManager cm = createNewCacheManager(); // no discovery here
>>> c1 = cm.getCache("clustered cache 1"); // this will involve starting the Transport, and hence discovery
>>> c2 = cm.getCache("clustered cache 2"); // no discovery here; cache1 already started the Transport
>>> c1.stop();
>>> cm.getCache("clustered cache 3") // again, discovery here; cache1 already started the Transport
>>> 
>>> HTH
>>> Manik
>>> 
>>> 
>>>> 
>>>> [1] 
>>>> http://anonsvn.jboss.org/repos/jbossas/projects/cluster/ha-server-cache-jbc/trunk/src/main/java/org/jboss/ha/cachemanager/CacheManager.java
>>>> 
>>>>> TBH I think the 3) suggestion should be okay, and the users should be aware that they should only  all stop() from one thread only. That is because the cache is rather a collection of data rather than a connection to something, and destroying it shouldn't be done each time you access it but only at the beginning and the end of your app.
>>>>> 
>>>> 
>>>> Agreed. With JBC there was a major use case for sharing caches across 
>>>> unrelated applications. With Infinispan I don't see that being the case.
>>>> 
>>>> Also, CacheManager is an interface, so just like w/ JBC if the AS needs 
>>>> some special behavior it can have its own implementation and push stuff 
>>>> back upstream if appropriate.
>>>> 
>>>>> On Dec 14, 2009, at 12:33 PM, Manik Surtani wrote:
>>>>> 
>>>>>> This is a good point, Brian.
>>>>>> 
>>>>>> Perhaps Cache.stop() should delegate to CacheManager.stopCache(cacheName) and as you say, some form of reference counting may be in order.
>>>>>> 
>>>>>> However, calling CacheManager.stopCache(cacheName) could be overloaded (a boolean "force" flag?) to stop the cache, regardless of known references?
>>>>>> 
>>>> 
>>>> Sounds good.
>>>> 
>>>>>> Cheers
>>>>>> Manik
>>>>>> 
>>>>>> 
>>>>>> On 11 Dec 2009, at 20:37, Brian Stansberry wrote:
>>>>>> 
>>>>>>> Had a look at DefaultCacheManager today and I see it has no mechanism
>>>>>>> for controlling the stopping of shared caches. Multiple independent
>>>>>>> callers to getCache("foo") can get a ref to the foo cache, and then any
>>>>>>> of them can call stop() on it.
>>>>>>> 
>>>>>>> A few possibilities come to mind:
>>>>>>> 
>>>>>>> 1) Add a releaseCache method, do some reference counting, and stop the
>>>>>>> cache when all refs are released. Remove the cache from the "caches" map.
>>>>>>> 
>>>>>>> 2) And/or, wrap the cache in a wrapper whose stop() method doesn't call
>>>>>>> through to the wrapped cache until stop() is called on all wrappers
>>>>>>> 
>>>>>>> 3) Advise in the javadoc that shared caches are supported, but if they
>>>>>>> are used it's the users responsibility to ensure that at least one but
>>>>>>> only one caller calls stop() on the cache. At least for the AS use
>>>>>>> cases, this should be OK, since an Infinispan Cache will be analogous to
>>>>>>> a JBC Region, and there's only one user for a given region.
>>>>>>> 
>>>>>>> --
>>>>>>> Brian Stansberry
>>>>>>> Lead, AS Clustering
>>>>>>> JBoss by Red Hat
>>>>>>> _______________________________________________
>>>>>>> infinispan-dev mailing list
>>>>>>> infinispan-dev at lists.jboss.org
>>>>>>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
>>>>>> 
>>>>>> --
>>>>>> Manik Surtani
>>>>>> manik at jboss.org
>>>>>> Lead, Infinispan
>>>>>> Lead, JBoss Cache
>>>>>> http://www.infinispan.org
>>>>>> http://www.jbosscache.org
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> _______________________________________________
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>>>>>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
>>>>> 
>>>>> 
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>>>> 
>>>> 
>>>> -- 
>>>> Brian Stansberry
>>>> Lead, AS Clustering
>>>> JBoss by Red Hat
>>>> _______________________________________________
>>>> infinispan-dev mailing list
>>>> infinispan-dev at lists.jboss.org
>>>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
>>> 
>>> --
>>> Manik Surtani
>>> manik at jboss.org
>>> Lead, Infinispan
>>> Lead, JBoss Cache
>>> http://www.infinispan.org
>>> http://www.jbosscache.org
>>> 
>>> 
>>> 
>>> 
>>> 
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>>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
>> 
>> 
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> 
> --
> Manik Surtani
> manik at jboss.org
> Lead, Infinispan
> Lead, JBoss Cache
> http://www.infinispan.org
> http://www.jbosscache.org
> 
> 
> 
> 
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