Storage, Execution & Recovery Internals
Database System Architecture
A DBMS is a set of cooperating control planes: SQL is parsed and bound into a logical statement, rewritten and optimized into a physical plan, executed against transactional storage, and supported by logging, cache, and maintenance services. The boundaries vary by engine; the data and durability invariants do not.
- The catalog gives names physical meaning.
- Rewrite and optimization answer different questions.
- Execution crosses concurrency and storage boundaries.
- Background work is part of foreground correctness.
- Component boundaries are not universal APIs.
- Queues reveal overload location.
| Stage | Consumes | Produces / invariant |
|---|---|---|
| Parse | SQL text | Syntax tree; no object identity yet |
| Bind/catalog | Tree + metadata snapshot | Resolved and typed statement |
| Rewrite/optimize | Logical semantics + statistics | Equivalent executable strategy |
| Execute | Plan + transaction context | Rows/effects under visibility rules |
| Storage/recovery | Page requests + log records | Durable, recoverable state |