Hi Mark, Many thanks for giving this a try; Your work looks impressive, it's very advanced for an initial dialect contribution, covering many advanced cases already. So kudos for that!
Please find some remarks and questions below. Cheers, --Gunnar 2015-07-17 17:16 GMT+02:00 Mark Paluch <mpal...@paluch.biz>: > Hi there, > > I created a Redis module for Hibernate OGM, based on OGM 4.2. Redis is a > Key-Value store supporting Lists, Hashes (Maps), Sorted Sets, ... > > I took the Infinispan/CouchDB approach storing entities and associations as > JSON documents within Redis Hashes. A Map<Object, Map<Object, Object>> > corresponds with a Redis Hash. > > The entity table maps to the Hash Id, the entity Id to the key of the hash > and the set of columns is enclosed within a JSON (currently). Supported > features are: > > * Composite Id's > * Embedded associations > * External associations > * I saw you create a hash per entity type, using the ids as keys within this hash and a JSON document modelling the properties of a given entity instance. Have you considered to store JSON documents on the "top-level" instead? This would require to encode the table name into the key as well (similar to as we do it for CouchDB): "Order:123" -> ... . The reason I am asking is that I am wondering whether it may be a source of contention and/or whether it may pose scaling issues if all entities of one type are stored within a single hash. Using JSON for the actual entity contents seems reasonable and a common approach in the Redis world from what I've read, so +1 for doing this from me. How would the "more native" approach look like you describe below? Would we have to serialise everything ourselves into String/byte[]? If so, I am not sure whether that's of much usefulness actually and I'd be inclined to go the JSON route exclusively. As you say, it also works nicely for hierarchical structures. * The id is used as key and also part of the JSON value. Could it be removed from the latter? * Do you have any ideas how Redis-specific structures could be exposed which do not map exactly to entities, e.g. Lists stored directly via some key? * Our option system could be used to expose specific settings such as TTL for given entities * Is there any form of transaction support in Redis we could leverage? and I guess many more, that I'm currently not aware of :-) > > There are various ways (JSON, Java-serialized simulating Documents) how to > store data within Redis. > Another approach could be storing Tuples within Redis more native, since > they are in the end Maps, somehow. However, mapping tuples to Redis fit a > native storage but raises questions about Id's, limited data type support > (there is no equivalent for nested lists/maps). So the more native approach > would require distributing data amongst various data types, depending on > the supported features, and would require more IO's. > > My impl can be used to interoperate with other clients from the C, Ruby, > Python, Node.js, ... worlds. The JSON is clean and does not look awkward on > the first look. > > The current code can be found below > https://github.com/mp911de/hibernate-ogm/tree/redis. Most TCK tests pass, > only some 15 tests fail. Mostly due to enum and JTA support. Couldn't > figure out, how to fix it, so need your help to figure it out. > I'll take a closer look at your change asap. Could you create a pull request from your branch against the upstream repo? Then we can have a discussion right there. Hope, I made you hungry for the Redis OGM module. Let's start a discussion > based on my proposal for inclusion and let's see, where we end up. > Yep, it looks very promising and I think it'd be great to have support for Redis in OGM :) We'll need your continued help though to make it happen and evolve it in the future as Redis itself and OGM core advance. Best regards, Mark > _______________________________________________ > hibernate-dev mailing list > hibernate-dev@lists.jboss.org > https://lists.jboss.org/mailman/listinfo/hibernate-dev > _______________________________________________ hibernate-dev mailing list hibernate-dev@lists.jboss.org https://lists.jboss.org/mailman/listinfo/hibernate-dev
