How does FlockDB compare with neo4j?

hop of those help? Flockdb is still Yet to be released by Twitter, which means the current version you are seeing won't run properly. Going by the history of commits i guess within a couple of days you can see a stable version which you can build and test.
Compared to something like Neo4J you can say Flockdb is not even a graph database. The toughest part of a graph database is how many levels of depth it can handle. From the little documentation of Flockdb it seems like it can't handle more than 1 level of depth. Where FlockDb wins compared to DBs like Neo4J is it's low latency, high throughput and inherent distributed nature.

I wish this helpful for you This answer should be taken with a healthy dosage of salt because I'm not 100% about your requirements.
First and most obviously, this paper is from Twitter (Personilised page ran - SALSA). I know at some point the head of their recommendations / personalisation said they used it with a bunch of other techniques (This is from Oct'11) https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-snc7/300267_581958426587_2140504611_n.jpg

hope this fix your issue Not sure that lists of parameters are converted. Single entities are converted into their id's.
So if you convert the Criterions into their graph-id's you can do:

@Query("MATCH (c:Criterion) WHERE ID(c) IN {0} return c")
List<Criterion> getAllCriteria(List<Long> criteria);

I think the issue was by ths following , I have a following query. The goal of the query is to get all the nodes except certain nodes , The exception is for this line :

WHERE NOT exist(u.password) AND NOT u

WHERE NOT EXISTS(u.password)
AND u1 <> u