[xwiki-devs] [Proposal] Strategy for migrating to the new Model

Hi devs, Just wanted to share my vision of how we should tackle migrating to the new Model. I see the following steps: * Step 1: Define new model interfaces (status: in progress) * Step 2: Implement a "bridged" version which uses the oldcore (status: in progress). * Step 3: Start moving code to use the new API as the new API and its implementation progress. Note: we should start using the produce of step1 and step2 ASAP to tune the details (status: not started) * Step 4: At the same time, start a new implementation based on a RDBMS (probably hibernate-based, to be decided) (status: not started). I'd also like that we start other implementations not based on a RDBMS just to prove that it works with other storages. Ideally I'd like some NoSQL impl (Caleb maybe?) and I'd also like to try a Git-based implementation (using jgit) * Step 5: Deprecate all our search apis located in XWikiHibernateStore and make everyone use the new QueryManager module. This needs some tuning on the QueryManager for missing stuff but that's doable (I need to send some proposal on missing stuff). (status: in progress). The idea here is to decouple search from storage. Note that we'll need to write some translator from HQL to XWQL or the new search query language. * Step 6: As we progress in step 2, 3, 4, introduce a configuration parameter to decide which implementation to use ("bridged", etc) so that users can start playing with new implementations (status: not started) * Step 7: Rewrite a new Importer/Exporter that exports everything (all the data in the current DB) + all configuration files/data. To see what we are currently not exporting, see http://platform.xwiki.org/xwiki/bin/view/AdminGuide/Backup#HUsingtheXWikiEx… This new exporter should probably be based on the XWiki Streams module being developed here: https://github.com/xwiki-contrib/wiki-stream (status: in progress but not active) * Step 8: When users want to migrate from one implementation ("bridged" for ex) to a new implementation they export their wiki, set the new implementation in the configuration file and reimport. (status: not started) For me Step3 can almost begin (I probably need one or 2 more weeks to be ready to have some use cases implemented and I'll send a vote to merge my work in feature-newmodel branch in master - Would be good if you guys start looking at it and give comments to be ready for this). Then we need volunteer for Step 4 for: * new RDBMS implementation. Who? * noSQL impl. Cassandra? other? Who? * git implementation. Vincent WDYT about the plan? In term of time required it's probably going to take us about a year to have a first working version for all the steps by working at a leisurely pace. Thanks -Vincent