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

On Jan 15, 2014, at 1:42 PM, Emmanuel Bernard <emmanuel(a)hibernate.org&gt; wrote: > By the way, people looking for that feature are also asking for a unified Cache API accessing these several caches right? Otherwise I am not fully understanding why they ask for a unified query. > Do you have written detailed use cases somewhere for me to better understand what is really requested? IMO from a user perspective, being able to run queries spreading several caches makes the programming simplifies the programming model: each cache corresponding to a single entity type, with potentially different configuration.

Besides the query API that would need to be extended to support accessing multiple caches, not sure what other APIs would need to be extended to take advantage of this? > > Emmanuel > > On 14 Jan 2014, at 12:59, Sanne Grinovero <sanne(a)infinispan.org&gt; wrote: > >> Up this: it was proposed again today ad a face to face meeting. >> Apparently multiple parties have been asking to be able to run >> cross-cache queries. >> >> Sanne >> >> On 11 April 2012 12:47, Emmanuel Bernard <emmanuel(a)hibernate.org&gt; wrote: >>> >>> 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 >> _______________________________________________ >> 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 Cheers, -- Mircea Markus Infinispan lead (www.infinispan.org) _______________________________________________ infinispan-dev mailing list infinispan-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/infinispan-dev