{"id":"write-time-decisions-are-lightweight-but-binding","text":"Systems that route at write time push only lightweight references (post IDs, inbox pointers) and defer data hydration to reads — but these routing decisions are permanently locked in at write time with no retroactive correction mechanism, meaning a fast, cheap write path produces irrevocable outcomes.","truth_value":"IN","source":"","source_url":"","source_hash":"","justifications":[{"type":"SL","antecedents":["fan-out-write-pushes-references-not-data","write-time-routing-is-irrevocable"],"outlist":[],"label":"Fan-out pushes references (lightweight) and routing decisions are permanent (binding) — the write path optimizes for speed at the cost of flexibility"}],"dependents":["symmetric-graphs-enable-complete-lightweight-routing","write-path-eliminates-coordination-across-identity-and-routing","write-path-is-self-consistent-by-design","writes-are-cheap-reads-pay"],"metadata":{"last_reviewed":"2026-06-06T06:26:57","review_result":"pass"},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"write-time-decisions-are-lightweight-but-binding","truth_value":"IN","reason":"SL justification valid","antecedents":["fan-out-write-pushes-references-not-data","write-time-routing-is-irrevocable"],"label":"Fan-out pushes references (lightweight) and routing decisions are permanent (binding) — the write path optimizes for speed at the cost of flexibility"},{"node":"fan-out-write-pushes-references-not-data","truth_value":"IN","reason":"SL justification valid","antecedents":["chat-fanout-on-write","news-feed-fan-out-write-pushes-ids"],"label":"Reference-based fanout limits write amplification to pointer-sized payloads"},{"node":"chat-fanout-on-write","truth_value":"IN","reason":"premise"},{"node":"news-feed-fan-out-write-pushes-ids","truth_value":"IN","reason":"premise"},{"node":"write-time-routing-is-irrevocable","truth_value":"IN","reason":"SL justification valid","antecedents":["news-feed-celebrity-threshold-at-write-time","chat-fanout-on-write"],"label":"news feed selects fan-out-on-write vs fan-out-on-read based on follower count at publish time; chat routes to inbox or offline queue based on presence at send time — both decisions are baked in at write time and not revisited"},{"node":"news-feed-celebrity-threshold-at-write-time","truth_value":"IN","reason":"premise"}]}}