{"id":"hash-index-all-keys-in-memory","text":"Both Bitcask implementations keep every live key in an in-memory dict (`keydir` / `_index`), meaning the key set must fit in RAM; there is no disk-based fallback for partial index spill.","truth_value":"IN","source":"entries/2026/05/29/topic-ddia-chapter3-hash-indexes.md","source_url":"","source_hash":"","justifications":[],"dependents":["hash-index-is-memory-bound-by-design"],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"hash-index-all-keys-in-memory","truth_value":"IN","reason":"premise"}]}}