In order to fully maintain data integrity and ensure good transactional behavior, Neo4j supports the ACID properties:
- atomicity: If any part of a transaction fails, the database state is left unchanged.
- consistency: Any transaction will leave the database in a consistent state.
- isolation: During a transaction, modified data cannot be accessed by other operations.
- durability: The DBMS can always recover the results of a committed transaction.
- All database operations that access the graph, indexes, or the schema must be performed in a transaction.
- The default isolation level is
- Data retrieved by traversals is not protected from modification by other transactions.
- Non-repeatable reads may occur (i.e., only write locks are acquired and held until the end of the transaction).
- One can manually acquire write locks on nodes and relationships to achieve higher level of isolation (
- Locks are acquired at the Node and Relationship level.
- Deadlock detection is built into the core transaction management.