pinterest_graph.adoc

The Pinterest Graph

This GraphGist is inspired by the blog Building a follower model from scratch, kudos to the Pinterest Engineers!

The model

The basic model is just users following users, something like the following.

CREATE (anders:User{name:'Anders'})
CREATE (michael:User{name:'Michael'})
CREATE (peter:User{name:'Peter'})
CREATE (peter)-[:owns_board]->(board1:Board{name:'board1'})
CREATE (peter)-[:owns_board]->(board2:Board{name:'board2'})
CREATE (peter)-[:owns_board]->(board3:Board{name:'board3'})
CREATE (anders)-[:follows_user]->(michael)

Action: User follows board

When a user follows a board, an explicit relationship can be created in the model.

MATCH (anders:User), (board1:Board)
WHERE anders.name='Anders' and board1.name='board1'
//create the follow relatoinship to board1
CREATE (anders)-[:follows_board]->(board1)

Find all users followed by Anders (exclicit and implicit)

With the explicit relationships, we can now infer all users that are of interest to the first user Anders. Some quirk is made here to get both categories returned in one column.

MATCH
//explicitly following users
(user:User)-[:follows_user]->(expl_following),
//implicitly following users via followed boards
user-[:follows_board]->()<-[:owns_board]-(impl_following)
WHERE user.name='Anders'
RETURN expl_following, impl_following