Re: [infinispan-dev] Infinispan Query entity discovery (Was: Re: new Infinispan Query API - ISPN-194)

Infinispan Query as it might not have discovered all types yet (1)

2011/4/29 Israel Lacerra <israeldl(a)gmail.com&gt;: > What about use D) and also give a way to user specify the default classes to > all queries? Yes that's the idea; but we need to figure out how the user specifies the default classes; so far nobody liked any proposal. Sanne > > On Wed, Apr 27, 2011 at 5:10 AM, Emmanuel Bernard < emmanuel(a)hibernate.org&gt; > wrote: >> >> On 27 avr. 2011, at 08:57, Sanne Grinovero wrote: >> >> > 2011/4/27 Emmanuel Bernard <emmanuel(a)hibernate.org&gt;: >> >> Users can put indexed or nit indexed superclasses in the query target >> >> type. That would not work for you as you can't discover known subtypes wo >> >> scanning or having a closure of types somewhere. >> > >> > sure they can with Hibernate Search. but should they be able with >> > Infinispan Query? >> > If the answer is yes, then we still need to find an alternative. >> >> Well it's an OO query and thus subtype polymorphism should apply. >> >> > >> > >> >> On 26 avr. 2011, at 23:32, Sanne Grinovero < sanne.grinovero(a)gmail.com&gt; >> >> wrote: >> >> >> >>> Hello, >> >>> I'm forking off this thread, as we never resolved how to cope with the >> >>> main issue: >> >>> >> >>> how is Infinispan Query going to be aware of which entities are to be >> >>> considered as default targets for a Query? >> >>> >> >>> the realistic ideas so far: >> >>> A) class scanning: seems nobody liked this idea, but I'll still >> >>> mention it as the other options aren't looking great either. >> >>> B) scan known indexes (need to define what the "known indexes" are as >> >>> we usually infer that from the classes) >> >>> -- could enforce a single index >> >>> C) have to list all fully qualified class names in the configuration >> >>> D) don't care: consider it a good practice to specify all targeted >> >>> types when performing a Query. >> >>> E) please suggest :) >> >>> >> >>> The currently implemented solution is D, as it requires no coding at >> >>> all :) >> >>> considering the simplicity of it I'm liking it more the more I think >> >>> about it; I could even polish the approach by adding a single line to >> >>> log a warning when the user doesn't respect the best practice, or to >> >>> mandate it. >> >>> >> >>> Considering that when a Query is invoked specifying the target types >> >>> there is no doubt we know the classes, I could add a warning in case >> >>> the Query is performed without specifying the type: in that case it >> >>> usually implies the query targets all known types, which is always >> >>> fine when using Hibernate Search, but could be inconsistent with >> >>> Infinispan Query as it might not have discovered all types yet (1), so >> >>> a very simple solution is to mandate the type parameter. >> >>> >> >>> [1] - when the Cache interceptor hits an event adding a new type, the >> >>> Search engine is reconfigured. >> >>> >> >>> thoughts? >> >>> >> >>> Sanne >> >>> >> >>> >> >>> 2011/4/5 Emmanuel Bernard <emmanuel(a)hibernate.org&gt;: >> >>>> >> >>>> On 5 avr. 2011, at 13:38, Sanne Grinovero wrote: >> >>>> >> >>>>> 2011/4/5 Emmanuel Bernard <emmanuel(a)hibernate.org&gt;: >> >>>>>> >> >>>>>> On 5 avr. 2011, at 12:20, Galder Zamarreño wrote: >> >>>>>> >> >>>>>>> >> >>>>>>> On Apr 4, 2011, at 6:23 PM, Sanne Grinovero wrote: >> >>>>>>> >> >>>>>>>> </snip> >> >>>>>>>> >> >>>>>>>> there's one catch: >> >>>>>>>> when searching for a class type, it will only include results >> >>>>>>>> from >> >>>>>>>> known subtypes. The targeted type is automatically added to the >> >>>>>>>> known >> >>>>>>>> classes, but eventually existing subtypes are not discovered. >> >>>>>>>> >> >>>>>>>> Bringing this issue to an extreme, if the query is not targeting >> >>>>>>>> any >> >>>>>>>> type, and no indexed types where added to the grid (even if some >> >>>>>>>> exist >> >>>>>>>> already as they might have been inserted by other JVMs or >> >>>>>>>> previous >> >>>>>>>> runs), all queries will return no results. >> >>>>>>>> How to solve this? >> >>>>>>>> - class scanning? >> >>>>>>> >> >>>>>>> Nope, too expensive. >> >>>>>>> >> >>>>>>>> - explicitly list indexed entities in Infinispan configuration? >> >>>>>>> >> >>>>>>> No >> >>>>>>> >> >>>>>>>> - a metadata cache maintaining a distributed&stored copy of known >> >>>>>>>> types >> >>>>>>> >> >>>>>>> That sounds more appealing. It could be a good middle ground until >> >>>>>>> Search can search for types. >> >>>>>> >> >>>>>> Do you have any specific idea in mind? >> >>>>>> >> >>>>>> To magically find types: >> >>>>>> - we scan every file system, databases, caches available to the >> >>>>>> app and look for Lucene metadata => unrealistic >> >>>>>> - there is some kind of convention on where the indexes are and we >> >>>>>> do index scanning at startup => scanning are very likely to be slower that >> >>>>>> class scanning (potential remote access, bigger dataset etc) >> >>>>>> - we enforce one or a fixed number of Lucene indexes for all data >> >>>>>> in Infinispan => not sure that's a good idea but this can be explored >> >>>>>> - we somehow ask the framework using HSearch to fill up classes >> >>>>>> >> >>>>>> other approaches? >> >>>>> >> >>>>> why was class scanning discarded in the first answer? as H. Search >> >>>>> can >> >>>>> auto-discover classes by working on top of JPA entity autodiscovery, >> >>>>> I >> >>>>> guess that each application node could look into it's own known >> >>>>> classpath. >> >>>>> After all if some type is not visible to him as it was added from >> >>>>> another node from a different app, he won't be able to return >> >>>>> instances of it either. >> >>>>> We could face the opposite problem of building metadata of classes >> >>>>> people doesn't mean to index in this cache. >> >>>> >> >>>> Right. scanning (class or index) will be a bit aggressive and could >> >>>> build unneeded metadata (or even worse, return unexpected classes). >> >> >> >> >> _______________________________________________ >> infinispan-dev mailing list >> infinispan-dev(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/infinispan-dev > >