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

On Jan 30, 2014, at 9:42 AM, Galder Zamarreño <galder(a)redhat.com&gt; wrote: > On Jan 21, 2014, at 11:52 PM, Mircea Markus <mmarkus(a)redhat.com&gt; wrote: > >> 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. > Not sure if it simplifies things TBH if the configuration is the same. IMO, it just adds clutter. Not sure I follow: having a cache that contains both Cars and Persons sound more cluttering to me. I think it's cumbersome to write any kind of querying with an heterogenous cache, e.g. Map/Reduce tasks that need to count all the green Cars would need to be aware of Persons and ignore them. Not only it is harder to write, but discourages code reuse and makes it hard to maintain (if you'll add Pets in the same cache in future you need to update the M/R code as well). And of course there are also different cache-based configuration options that are not immediately obvious (at design time) but will be in the future (there are more Persons than Cars, they live longer/expiry etc): mixing everything together in the same cache from the begging is a design decision that might bite you in the future. The way I see it - and very curious to see your opinion on this - following an database analogy, the CacheManager corresponds to an Database and the Cache to a Table. Hence my thought that queries spreading multiple caches are both useful and needed (same as query spreading over multiple tables).