Prefer using custom IDs for node/relationship - Amazon Neptune

Prefer using custom IDs for node/relationship

Neptune allows users to explicitly assign IDs on nodes and relationships. The ID must be globally unique in the dataset and deterministic to be useful. A deterministic ID can be used as a lookup or a filtering mechanism just like properties; however, using an ID is much more optimized from query execution perspective than using properties. There are several benefits to using custom IDs -

  • Properties can be null for an existing entity, but the ID must exist. This allows the query engine to use an optimized join during execution.

  • When concurrent mutation queries are executed, the chances of concurrent modification exceptions (CMEs) are reduced significantly when IDs are used to access nodes because fewer locks are taking on IDs than properties due to their enforced uniqueness.

  • Using IDs avoids the chance of creating duplicate data as Neptune enforces uniqueness on IDs, unlike properties.

The following query example uses a custom ID:

Note

The property ~id is used to specify the ID, whereas id is just stored as any other property. 

CREATE (n:Person {`~id`: '1', name: 'alice'})

Without using a custom ID: 

CREATE (n:Person {id: '1', name: 'alice'})

If using the latter mechanism, there is no uniqueness enforcement and you could later execute the query: 

CREATE (n:Person {id: '1', name: 'john'})

This creates a second node with id=1 named john. In this scenario, you would now have two nodes with id=1, each having a different name - (alice and john).