{"id":"lsm-requires-wal-hash-does-not","text":"The LSM tree uses a separate WAL (`lsm.py:14-64`) for crash recovery because its memtable is volatile; the hash index writes directly to the append-only data file, which serves as its own recovery log and needs no WAL.","truth_value":"IN","source":"entries/2026/05/29/topic-ddia-chapter3-hash-indexes.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"explanation":{"steps":[{"node":"lsm-requires-wal-hash-does-not","truth_value":"IN","reason":"premise"}]}}