Neo4j cypher query poor performance

Question

I have these nodes:

1. user{user_id}: users
2. thread{thread_id, published_date, like_count, comment_count, view_count}: posts
3. tag_id{tag_id}: the tag of the post

And these relationships:

1. (user) - [: FOLLOWED] -> (tag) // the user follows the tag
2. (thread) - [: BELONG_TO] -> (tag) // the post belongs to tag
3. (user) - [: READ] -> (thread) // user reads the post

Now I want to query 5 posts belong to tag user follow user has not read that thread, and that thread must be up to date, order by point DESC. I created index on User(user_id), Tag(tag_id), Thread(thread_id) and i run this cypher query from the browser:

MATCH (u:User)-[:FOLLOWED]->(t:Tag)<-[:BELONG_TO]-(th)
WHERE u.user_id = 3 AND NOT EXISTS((u)-[:READ]->(th))
WITH u.user_id AS user_id, th.thread_id AS thread_id,
t.tag_id AS tag_id,duration.inDays(datetime(),
datetime(th.published_date)).days AS days,
(0.5*th.like_count + 0.3*th.comment_count + 0.2*th.view_count) AS point
ORDER BY days DESC
RETURN DISTINCT thread_id SKIP 0 LIMIT 5

With just 1 node in database (also embedded ) took 235 ms. Obviously something is going wrong. What could be the problem. Pleace hepl me

Answer 1

In your MATCH you have a bi-directional pattern.

(t:Tag)<-[:BELONG_TO]->(th)

Do you have set an index or constraint on :User(user_id) ?