{"id":"system-has-no-undo-at-any-layer","text":"No layer in the system can reverse a completed operation: the WAL stores only new values with no before-images (making rollback structurally impossible), and transaction abort is a status-flag change that leaves all written versions on disk, meaning neither the storage layer nor the logical transaction layer supports undo.","truth_value":"IN","source":"","source_url":"","source_hash":"","justifications":[{"type":"SL","antecedents":["wal-has-no-before-images","abort-is-status-change-not-disk-rollback"],"outlist":[],"label":"WAL redo-only format and MVCC status-only abort independently confirm no undo capability exists at any layer"}],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"system-has-no-undo-at-any-layer","truth_value":"IN","reason":"SL justification valid","antecedents":["wal-has-no-before-images","abort-is-status-change-not-disk-rollback"],"label":"WAL redo-only format and MVCC status-only abort independently confirm no undo capability exists at any layer"},{"node":"wal-has-no-before-images","truth_value":"IN","reason":"premise"},{"node":"abort-is-status-change-not-disk-rollback","truth_value":"IN","reason":"premise"}]}}