feat: add graph queries timeout

[tipogi]

Pre-submission Checklist

For tests to work you need a working neo4j and redis instance with the example dataset in docker/db-graph

• Testing: Implement and pass new tests for the new features/fixes, cargo test.
• Performance: Ensure new code has relevant performance benchmarks, cargo bench

[tipogi]

There are two ways to apply a timeout to queries in Neo4j:

Global timeout

To set a global timeout for all transactions, modify the neo4j.conf configuration file. In that branch, the file path would be docker/.database/neo4j/conf/neo4j.conf:

db.transaction.timeout=1s

Verifying the Configuration

To verify if the global timeout configuration was successfully applied (after restarting the container), execute the following Cypher command:

CALL dbms.listConfig() YIELD name, value
WHERE name = 'db.transaction.timeout'
RETURN name, value;

Testing the Global Timeout

Run a query that exceeds the specified timeout, such as:

UNWIND range(1, 1000000000) AS i
RETURN i;

If the timeout is configured correctly, you should receive an error indicating that the query has timed out

Per query timeout

For more customized query timeouts, the APOC plugin is required. Follow these steps

Configuring the APOC Plugin

1. Download the APOC plugin from the releases page.
2. Move the downloaded .jar file to the plugins directory in our Neo4j setup, docker/.database/neo4j/plugins
3. Add Apoc configuration in docker-compose.yml

NEO4JLABS_PLUGINS: '["apoc"]'
NEO4J_dbms_security_procedures_unrestricted: 'apoc.*'
NEO4J_dbms_security_procedures_allowlist: 'apoc.*'

Restarting the Neo4j Container

1. Remove the data folder from the Neo4j directory (docker/.database/neo4j/data) to reset the database.
2. Restart the container to apply the changes

Using Per Query Timeout

Once the plugin is installed and the container is restarted, you can apply a timeout to specific queries using apoc.cypher.runTimeboxed

CALL apoc.cypher.runTimeboxed("MATCH (u1:User)-[f:FOLLOWS]-(u2:User)
 RETURN u1, f, u2",
 {}, 20)

If any query exceeding this limit will terminate with an error

[SHAcollision]

There are two ways to apply a timeout to queries in Neo4j:

Really excellent research and summary. Thank you for taking the time!