On 1 June 2016 at 15:24, Ryan Emerson <remer...@redhat.com> wrote: > After further discussions on IRC, we have concluded the following: > > In shared mode only the primary owner of a key writes to the shared store, > therefore there is no obvious use-case for having a singleton mode which > delegates all writes to a single node.
As far as I remember, the *intent* was to allow dealing with stores which can't handle concurrent writes, i.e. needing a global lock. We had different CacheStore implementations back then, I guess some of them might have had exotic limitations. I don't know which practical use case people had in mind though: it's likely we already dropped any implementation which could need this long ago, so no objections about getting rid of it. Thanks, Sanne > > With this in mind, I propose that the singleton option and associated > writers be deprecated [1]. If anybody has any objections, please speak up. > > [1] https://issues.jboss.org/browse/ISPN-6748 > > Cheers > Ryan > > ----- Original Message ----- > From: "William Burns" <mudokon...@gmail.com> > To: "infinispan -Dev List" <infinispan-dev@lists.jboss.org> > Cc: d...@infinispan.org, remer...@redhat.com > Sent: Wednesday, 1 June, 2016 2:54:13 PM > Subject: Singleton Cache Stores with Shared Cache Stores > > Recently there was a start of a discussion regarding singleton cache stores > and how they behave. Interestingly according to our documentation [1] and > verification code [2] a singleton store cannot be used with a shared cache > store. This makes no sense to me as this means you would have a single > point of failure for your data. And also as Dan pointed out [3] there is > no Singleton cache loader to make sure all the loads are from the > coordinator either, which means you could have a read that returns null > despite it being in the store/loader. > > And even looking at [4] it talks about singleton being used so not every > node writes to the underlying store, which implies it being shared. > > I think we have enough proof to update this so a singleton store requires a > shared store, but I wanted to make sure we weren't missing something here. > > Thanks, > > - Will > > [1] > http://infinispan.org/docs/9.0.x/user_guide/user_guide.html#_configuration_2 > [2] > https://github.com/infinispan/infinispan/blob/master/core/src/main/java/org/infinispan/configuration/cache/PersistenceConfigurationBuilder.java#L108 > [3] https://github.com/infinispan/infinispan/pull/4382#discussion_r65360312 > [4] > https://github.com/infinispan/infinispan/blob/master/core/src/main/java/org/infinispan/persistence/support/SingletonCacheWriter.java#L40 > _______________________________________________ > infinispan-dev mailing list > infinispan-dev@lists.jboss.org > https://lists.jboss.org/mailman/listinfo/infinispan-dev _______________________________________________ infinispan-dev mailing list infinispan-dev@lists.jboss.org https://lists.jboss.org/mailman/listinfo/infinispan-dev
