{"id":"logical-physical-separation-spans-topology-storage-and-deletion","text":"The architecture systematically separates logical semantics from physical state across three independent dimensions: topology (consistent hashing decouples ring positions from data placement, making node operations stateless), storage (message queue offsets survive partition trimming via base offset adjustment), and deletion (tombstones and delete markers decouple the logical fact of deletion from physical data removal), making logical-physical independence a cross-cutting architectural principle rather than a per-system choice.","truth_value":"IN","source":"","source_url":"","source_hash":"","justifications":[{"type":"SL","antecedents":["consistent-hashing-is-a-stateless-topology-abstraction","logical-abstraction-decouples-semantics-from-storage"],"outlist":[],"label":"Consistent hashing, queue offsets, and deletion metadata are three instances of the same logical-physical decoupling strategy"}],"dependents":["representation-decoupling-spans-module-and-architecture-scales","scaling-uses-logically-uniform-indirection"],"metadata":{"last_reviewed":"2026-06-06T06:26:57","review_result":"pass"},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"logical-physical-separation-spans-topology-storage-and-deletion","truth_value":"IN","reason":"SL justification valid","antecedents":["consistent-hashing-is-a-stateless-topology-abstraction","logical-abstraction-decouples-semantics-from-storage"],"label":"Consistent hashing, queue offsets, and deletion metadata are three instances of the same logical-physical decoupling strategy"},{"node":"consistent-hashing-is-a-stateless-topology-abstraction","truth_value":"IN","reason":"SL justification valid","antecedents":["ch-add-remove-idempotent","ch-migration-tracking-optional","ch-get-nodes-deduplicates-physical"],"label":"Idempotent ops + optional key tracking + auto-dedup = pure stateless routing function"},{"node":"ch-add-remove-idempotent","truth_value":"IN","reason":"premise"},{"node":"ch-migration-tracking-optional","truth_value":"IN","reason":"premise"},{"node":"ch-get-nodes-deduplicates-physical","truth_value":"IN","reason":"premise"},{"node":"logical-abstraction-decouples-semantics-from-storage","truth_value":"IN","reason":"SL justification valid","antecedents":["queue-abstraction-is-logical-not-physical","deletion-is-metadata-in-replicated-systems"],"label":"Message offsets and deletion metadata both create semantic layers that decouple consumers from physical storage state"},{"node":"queue-abstraction-is-logical-not-physical","truth_value":"IN","reason":"SL justification valid","antecedents":["message-delivery-guarantees-are-consumer-side","dmq-partition-offset-is-logical","dmq-dlq-is-regular-topic"],"label":"Consumer-side guarantees (depth-1) + logical offsets + DLQ-as-topic (both base) show the queue separates logical semantics from physical storage throughout"},{"node":"message-delivery-guarantees-are-consumer-side","truth_value":"IN","reason":"SL justification valid","antecedents":["dmq-delivery-semantics-in-poll","dmq-two-tier-offset-tracking"],"label":"The two-tier offset gap (current minus committed) is the mechanism that enables all three delivery modes — the broker just stores offsets, consumers choose semantics"},{"node":"dmq-delivery-semantics-in-poll","truth_value":"IN","reason":"premise"},{"node":"dmq-two-tier-offset-tracking","truth_value":"IN","reason":"premise"},{"node":"dmq-partition-offset-is-logical","truth_value":"IN","reason":"premise"},{"node":"dmq-dlq-is-regular-topic","truth_value":"IN","reason":"premise"},{"node":"deletion-is-metadata-in-replicated-systems","truth_value":"IN","reason":"SL justification valid","antecedents":["soft-delete-prevents-distributed-resurrection","append-only-versioning-makes-restore-non-destructive"],"label":"both depth-1 conclusions independently arrive at the same principle — never physically destroy data — but for complementary reasons (anti-resurrection vs non-destructive restore); combined they show this is a fundamental constraint of any system that replicates or versions state"},{"node":"soft-delete-prevents-distributed-resurrection","truth_value":"IN","reason":"SL justification valid","antecedents":["kv-store-deletes-use-tombstones","s3-delete-marker-hides-not-removes"],"label":"Both systems independently arrived at write-over-delete to prevent resurrection from unsynchronized replicas"},{"node":"kv-store-deletes-use-tombstones","truth_value":"IN","reason":"premise"},{"node":"s3-delete-marker-hides-not-removes","truth_value":"IN","reason":"premise"},{"node":"append-only-versioning-makes-restore-non-destructive","truth_value":"IN","reason":"SL justification valid","antecedents":["s3-version-list-append-only","gdrive-restore-creates-new-version"],"label":"Append-only version lists make restore a forward operation, not a rollback"},{"node":"s3-version-list-append-only","truth_value":"IN","reason":"premise"},{"node":"gdrive-restore-creates-new-version","truth_value":"IN","reason":"premise"}]}}