Pages, B-Trees, LSM Trees, and WALs
Storage engines organize durable state around page-sized I/O, ordered indexes, append-friendly structures, and logs that make recovery possible.
Planned model
Apply inserts and reads to a B-tree and an LSM-style design. Animate page splits, memtables, flushes, compaction, WAL records, and write amplification.
Questions
- Which writes must become durable before acknowledgement?
- Why do B-trees and LSM trees favor different workloads?
- Where do read, write, and space amplification arise?
Exercise
Choose a storage layout for an append-heavy workload with recent-key reads and state the compaction and recovery costs.