{"id":"wal-seq-num-is-monotonic-not-page-lsn","text":"WAL `seq_num` increases monotonically across all records but is not stamped onto data pages, so there is no mechanism to detect whether a replayed operation was already applied — making replay non-idempotent against the underlying store.","truth_value":"IN","source":"entries/2026/05/29/topic-redo-vs-undo-logging.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"explanation":{"steps":[{"node":"wal-seq-num-is-monotonic-not-page-lsn","truth_value":"IN","reason":"premise"}]}}