{"id":"mvcc-three-layer-visibility-model","text":"MVCC visibility is enforced through three complementary invariants: append-only version storage prevents lost updates, own-writes are always visible regardless of commit state, and deletions follow the same visibility rules as writes — collectively ensuring snapshot consistency.","truth_value":"IN","source":"","source_url":"","source_hash":"","justifications":[{"type":"SL","antecedents":["mvcc-append-only-versions","own-writes-always-visible","deletion-visibility-is-symmetric"],"outlist":[],"label":"Three independent visibility guarantees combine into a complete snapshot isolation model where no single invariant is sufficient alone"}],"dependents":["mvcc-isolation-survives-restart","transaction-isolation-composes-two-invariant-layers"],"metadata":{"last_reviewed":"2026-05-30T09:01:17","review_result":"pass"},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"mvcc-three-layer-visibility-model","truth_value":"IN","reason":"SL justification valid","antecedents":["mvcc-append-only-versions","own-writes-always-visible","deletion-visibility-is-symmetric"],"label":"Three independent visibility guarantees combine into a complete snapshot isolation model where no single invariant is sufficient alone"},{"node":"mvcc-append-only-versions","truth_value":"IN","reason":"premise"},{"node":"own-writes-always-visible","truth_value":"IN","reason":"premise"},{"node":"deletion-visibility-is-symmetric","truth_value":"IN","reason":"premise"}]}}