{"id":"representation-decoupling-spans-module-and-architecture-scales","text":"Representation decoupling operates at two architectural scales through the same principle: within modules, input representations are separated from storage representations (dataclasses vs dicts, coordinator writes vs raw replicas); across the architecture, logical semantics are separated from physical state (offsets survive partition trimming, hash positions decouple from topology, delete markers decouple from data removal) — both enabling independent evolution of interfaces and implementations at their respective granularities.","truth_value":"IN","source":"","source_url":"","source_hash":"","justifications":[{"type":"SL","antecedents":["input-and-storage-representations-are-decoupled","logical-physical-separation-spans-topology-storage-and-deletion"],"outlist":[],"label":"Representation decoupling at module scale and architecture scale are the same principle at different granularities"}],"dependents":[],"metadata":{"last_reviewed":"2026-06-06T06:26:57","review_result":"pass"},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"representation-decoupling-spans-module-and-architecture-scales","truth_value":"IN","reason":"SL justification valid","antecedents":["input-and-storage-representations-are-decoupled","logical-physical-separation-spans-topology-storage-and-deletion"],"label":"Representation decoupling at module scale and architecture scale are the same principle at different granularities"},{"node":"input-and-storage-representations-are-decoupled","truth_value":"IN","reason":"SL justification valid","antecedents":["email-service-input-storage-decoupling","kv-local-put-vs-raw-separation"],"label":"both decouple the external write representation from internal storage format"},{"node":"email-service-input-storage-decoupling","truth_value":"IN","reason":"premise"},{"node":"kv-local-put-vs-raw-separation","truth_value":"IN","reason":"premise"},{"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"}]}}