{"id":"fdatasync-never-used","text":"No implementation uses `os.fdatasync()`, missing a safe optimization for append-only WALs where only data (not metadata like mtime) needs to reach disk.","truth_value":"IN","source":"entries/2026/05/29/topic-fsync-flush-distinction.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"explanation":{"steps":[{"node":"fdatasync-never-used","truth_value":"IN","reason":"premise"}]}}