tl/dr: The technology we started building against (Titan) is probably dead. We're reopening the investigation for a backing technology.
Yesterday DataStax http://www.datastax.com/ announced http://www.datastax.com/2015/02/datastax-acquires-aurelius-the-experts-behind-titandb that they'd acquired http://www.datastax.com/2015/02/datastax-acquires-aurelius-the-experts-behind-titandb ThinkAurelius http://thinkaurelius.com/, the company for whom almost all the Titan developers work. The ZDNet article http://www.zdnet.com/article/datastax-snaps-up-aurelius-and-its-titan-team-to-build-new-graph-database/ made it pretty clear that they are killing the project
"We're not going to do an integration. The play here is we'll take everything that's been done on Titan as inspiration, and maybe some of the Titan project will make it into DSE Graph," DataStax engineering VP Martin Van Ryswyk said.
While its certainly possible that someone from the community will come out of the woodwork and continue Titan its now lost almost all of its top developers. It looks like there is some secret succession discussions going on but I'm not holding out hope that anything will come of it. This pretty much blows this project's schedule of having a hardware request by the end of the month and a publicly released beta at the end of March.
Anyway, we're reopening the investigation to pick a new backend. We're including more options than we had before as its become clear that open source graph databases is a bit of a wild west space. But there are people waiting on this. The developer summit made that clear. So we're not going to do the month long dive into each choice like we did last time. I'm not 100% sure exactly what we'll do but I can assure you we'll be careful.
I know you might want to talk about other options - you may as well stuff them on https://www.mediawiki.org/wiki/Wikibase/Indexing#Other_possible_candidates and we'll get to them. As always, you can check out our workboard https://phabricator.wikimedia.org/project/board/37/query/DwEBx9K4vaHo/ to see what we're actually working on.
Titan is still in the running assuming it gets active maintainers. OrientDB, which we evaluated last round, is still in there too. So too are GraphX and Neo4j. And ArangoDB. And Magnus' WDQ. We'd get much more involved in maintenance, I think. And writing a TinkerPop implementation Elasticsearch. That's not a serious contender. It'd get geo support for free but its really just a low bar to compare all the other options to.
Thanks,