SDE2 Interview Questions at Oracle

Explain Oracle's MVCC (Multi-Version Concurrency Control) and how it enables consistent reads without blocking writers. How does it differ from SQL Server's locking approach? What are the downsides of MVCC (undo log growth, long-running transactions)?

Design Oracle Cloud's IAM (Identity and Access Management) system. Thousands of customers, each with their own users, groups, and policies. How do you evaluate a permission check in under 10ms for every API call?

Explain Oracle's redo log and undo log. How do they work together to provide crash recovery and read consistency? Walk through what happens when a transaction commits, then the server crashes, then restarts.

Explain Oracle RAC (Real Application Clusters). How do multiple nodes access the same database storage? What is the Cache Fusion protocol? When would you choose RAC over a primary-replica setup?

Design a distributed SQL database that supports ACID transactions across shards. Explain two-phase commit (2PC), its failure modes, and how Google Spanner uses TrueTime to replace 2PC with a more scalable approach.

Oracle sells to enterprise clients with very long sales cycles. Describe a time you worked closely with a customer (internal or external) to solve a complex technical problem. How did you manage their expectations?