Java

Tell me about Cassandra: consistency, guarantees, features

How are partition key, clustering key, and secondary index organized in Cassandra?

Do you have any questions about the Adapter SMEF3 project?

What other options for solving the problem of concurrent write-offs exist (pessimistic locking, optimistic locking, serializable isolation)?

In which memory area is ConcurrentHashMap stored? Which container should be used for storing metrics?

PostgreSQL task: ensure balance consistency and protection against negative balance with 10 concurrent withdrawal requests.

How to speed up queries to a transaction table with a billion records over the last month for a specific account?

Task on multithreading: thread-safe metric collector with efficient increment, key — string, value — counter.

What is a consumer group in Kafka?

Do you write tests? What types of testing do you use?

What experience do you have with Redis? What data structures and commands have you used?

What are virtual nodes (vnodes) in Cassandra and how do transactions work?

What was the most challenging feature you are proud of?

Why is LongAdder more efficient than AtomicLong under high contention? Under what conditions does LongAdder work effectively?

Tell us about a complex authorization task when transitioning from monolith to microservices.

Why did you use a secondary index on status and updated_at in Cassandra? How did you perform analytical queries?

What is the GIN index used for in PostgreSQL?

What type of index should be used for querying account_id and created_at?

Tell us about delivery semantics in Kafka (at most once, at least once, exactly once)

Tell about your development experience and in which direction you want to grow?