OceanBase Internals: Transactions, Replay, SQL Engine, and Unit Placement
Why These Paths Matter OceanBase targets high availability and scalability in a shared-nothing cluster. The core engineering challenge is to make four critical subsystems work together with predictable latency and correctness: Write transactions must be durable, replicated, and efficiently committed. Tablet replay must recover state quickly and safely. SQL parse to execute must optimize well while respecting multi-tenant constraints. Unit placement must map tenants to physical resources without fragmentation. This article focuses on motivation, design, implementation highlights, and tradeoffs, using concrete code entry points from the OceanBase codebase. ...