[infinispan-dev] Remove cache issues

[Pedro Ruivo]

On 09/15/2015 01:46 PM, Dan Berindei wrote:
> On Mon, Sep 14, 2015 at 2:46 PM, Pedro Ruivo <pedro at infinispan.org> wrote:
>> Hi,
>>
>> I found the following issues with _EmbeddedCacheManager.removeCache()_
>> while I was helping the LEADS devs. The method removes the cache from
>> all the nodes in the cluster.
>>
>> #1 It has different behaviour in the invoker node.
>>
>> In the invoked node, it removes the configuration from
>> _configurationOverrides_ field and from _cacheDependencyGraph_. In the
>> remaining node, it doesn't.
>>
>> To think: it should remove from _cacheDependencyGraph_ in all the nodes
>> but keep the configuration.
>
> Galder added the _configurationOverrides_ removal for ISPN-3234, so
> I'm guessing JCache needs it.

You are right :)

>
> I guess the problem is that as long as the configuration exists,
> manager.getCache(name) will re-create the cache, and that doesn't fit
> with JCache. I'd rather remove the cache from _configurationOverrides_
> everywhere, at least until we stop auto-spawning caches.
>
>>
>> #2 It tries to remove the cache remotely before locally.
>>
>> It could be done in parallel and it has a small issue: if a timeout
>> occurs, it never tries to remove the cache locally.
>>
>> To think: can we send the request asynchronously?
>
> +1 to do it asynchronously

Well, the JCache docs does not say anything about it but, to be safe, 
I'll leave it synchronously.

>
>>
>> #3 When passivation is enabled, it first invoke
>> _PassivationManager.passivateAll()_ and then _PersistenceManager.stop()_.
>>
>> The former will copy all the data in memory to the cache store and the
>> later will clear the cache store. We can skip the passivation.
>>
>> To think: create a _PassivationManager.skipPassivationOnStop()_ (similar
>> to _PersistenceManager.setClearOnStop()_).
>
> Personally I was never really happy with removeCache() always purging
> the store. Although it makes sense for temporary caches, it means
> we're missing a way to just stop a cache on all the nodes.
>
> Maybe add a (mutable?) configuration option
> AbstractStoreConfiguration.purgeOnStop that could be referenced by
> both the PassivationManager and the PersistenceManager instead?

It sounds weird to have a per-store purgeOnStop. The PassivationManager 
will invoke the write() in PersistenceManager and it doesn't know if it 
is stopping or not.

I've put an option in PassivationManager (the same way as clearOnStop).

>
> Cheers
> Dan
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