Re: [infinispan-dev] Design change in Infinispan Query

On 10 avr. 2012, at 19:10, Sanne Grinovero wrote: > Hello all, > currently Infinispan Query is an interceptor registering on the > specific Cache instance which has indexing enabled; one such > interceptor is doing all what it needs to do in the sole scope of the > cache it was registered in. > > If you enable indexing - for example - on 3 different caches, there > will be 3 different Hibernate Search engines started in background, > and they are all unaware of each other. > > After some design discussions with Ales for CapeDwarf, but also > calling attention on something that bothered me since some time, I'd > evaluate the option to have a single Hibernate Search Engine > registered in the CacheManager, and have it shared across indexed > caches. > > Current design limitations: > > A- If they are all configured to use the same base directory to > store indexes, and happen to have same-named indexes, they'll share > the index without being aware of each other. This is going to break > unless the user configures some tricky parameters, and even so > performance won't be great: instances will lock each other out, or at > best write in alternate turns. > B- The search engine isn't particularly "heavy", still it would be > nice to share some components and internal services. > C- Configuration details which need some care - like injecting a > JGroups channel for clustering - needs to be done right isolating each > instance (so large parts of configuration would be quite similar but > not totally equal) > D- Incoming messages into a JGroups Receiver need to be routed not > only among indexes, but also among Engine instances. This prevents > Query to reuse code from Hibernate Search. > > Problems with a unified Hibernate Search Engine: > > 1#- Isolation of types / indexes. If the same indexed class is > stored in different (indexed) caches, they'll share the same index. Is > it a problem? I'm tempted to consider this a good thing, but wonder if > it would surprise some users. Would you expect that? I would not expect that. Unicity in Hibernate Search is not defined per identity but per class + provided id. I can see people reusing the same class as partial DTO and willing to index that. I can even see people using the Hibernate Search programmatic API to index the "DTO" stored in cache 2 differently than the domain class stored in cache 1. I can concede that I am pushing a bit the use case towards bad-ish design approaches. > 2#- configuration format overhaul: indexing options won't be set on > the cache section but in the global section. I'm looking forward to > use the schema extensions anyway to provide a better configuration > experience than the current <properties />. > 3#- Assuming 1# is fine, when a search hit is found I'd need to be > able to figure out from which cache the value should be loaded. > 3#A we could have the cache name encoded in the index, as part > of the identifier: {PK,cacheName} > 3#B we actually shard the index, keeping a physically separate > index per cache. This would mean searching on the joint index view but > extracting hits from specific indexes to keep track of "which index".. > I think we can do that but it's definitely tricky. > > It's likely easier to keep indexed values from different caches in > different indexes. that would mean to reject #1 and mess with the user > defined index name, to add for example the cache name to the user > defined string. > > Any comment? > > Cheers, > Sanne > _______________________________________________ > infinispan-dev mailing list > infinispan-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/infinispan-dev _______________________________________________ infinispan-dev mailing list infinispan-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/infinispan-dev