{"schema_version":1,"experiment_id":"eoa_inverse_innovation_exp09_archetype_breadth150_20260804","research_id":"eoa_inverse_innovation_exp09_light_prior_art_20260804","cell_id":"load_leveling_or_demand_smoothing__computer_science","search_lanes":{"direct_problem_and_intervention":{"queries":["cache stampede probabilistic early expiration VLDB Vattani","capacity-aware cache refresh expiration","cache refresh deadline scheduler backpressure headroom"],"source_ids":["SRC1","SRC2","SRC4"],"no_result_note":null},"synonyms_and_historical_terms":{"queries":["cache dogpile thundering herd refresh ahead synchronized TTL expiration","cache avalanche randomized TTL jitter refresh ahead origin overload","proactive cache warming preloading throttling server load queue"],"source_ids":["SRC1","SRC2","SRC3","SRC4"],"no_result_note":null},"products_practices_and_standards":{"queries":["site:blog.cloudflare.com cache stampede probabilistic early revalidation","site:aws.amazon.com cache refresh ahead jitter expiration load aware","load-aware cache refresh ahead"],"source_ids":["SRC2","SRC3","SRC4"],"no_result_note":null},"component_combination":{"queries":["deterministic jitter TTL cache refresh stable hash","deterministic cohort cache refresh expiry deadline","cache refresh scheduler capacity signal deadline urgent bypass"],"source_ids":["SRC2","SRC3","SRC4"],"no_result_note":"No retained source described the complete combination of deterministic per-client pre-expiry cohorts, authoritative-service headroom, urgent-class bypass, per-item completion deadlines, and forced re-entry."}},"sources":[{"source_id":"SRC1","title":"Optimal Probabilistic Cache Stampede Prevention","publisher":"Proceedings of the VLDB Endowment","url":"https://www.vldb.org/pvldb/vol8/p886-vattani.pdf","source_type":"PRIMARY_RESEARCH","claims_supported":["Concurrent regeneration after a cache item's expiration can overload or slow the backing system and amplify the stampede.","Probabilistic early expiration independently initiates regeneration before expiry and reduces simultaneous regeneration.","The paper presents and experimentally evaluates XFetch, an exponential early-expiration policy."]},{"source_id":"SRC2","title":"Sometimes I cache: implementing lock-free probabilistic caching","publisher":"Cloudflare","url":"https://blog.cloudflare.com/sv-se/sometimes-i-cache/","source_type":"FIRST_PARTY_PRODUCT","claims_supported":["Cloudflare demonstrates overload when requests simultaneously reach an origin after cache expiration.","Its production-oriented design probabilistically revalidates during a five-minute pre-expiry interval and unconditionally revalidates after expiry.","The source notes that early revalidation without dispersion merely moves the stampede earlier and that probabilistic scheduling lacks hard request-count guarantees."]},{"source_id":"SRC3","title":"Cache Validity - Database Caching Strategies Using Redis","publisher":"Amazon Web Services","url":"https://docs.aws.amazon.com/it_it/whitepapers/latest/database-caching-strategies-using-redis/cache-validity.html","source_type":"OFFICIAL_GUIDANCE","claims_supported":["AWS warns that simultaneous cache expiration under load can place excessive pressure on the backing database.","AWS recommends random TTL jitter to disperse expiration-related backend work.","TTL selection must account for the risk of returning outdated data."]},{"source_id":"SRC4","title":"Enable Cache Preloading","publisher":"Powered Cache","url":"https://docs.poweredcache.com/enable-preloading/","source_type":"FIRST_PARTY_PRODUCT","claims_supported":["Powered Cache runs cache preloading as queued background work and exposes remaining-item progress.","It spaces preload requests and permits interval adjustment to limit server load.","It monitors server load averages and pauses preloading when load or short-term spikes exceed thresholds."]}],"problem_evidence":{"status":"PARTLY_SUPPORTED","finding":"The expiry-correlated overload mechanism is directly visible: research, production practice, and official guidance document simultaneous regeneration or origin access after cache expiry and resulting backend pressure. The retained evidence does not directly measure independently deployed services refreshing the same versioned configuration, schema, or authorization metadata, so that exact operational scope remains unverified.","source_ids":["SRC1","SRC2","SRC3"]},"closest_prior_art":[{"name":"XFetch and Cloudflare probabilistic early revalidation","source_ids":["SRC1","SRC2"],"overlap":"Moves regeneration or revalidation into a bounded pre-expiry interval, disperses origin requests, and falls back to mandatory revalidation at expiry.","remaining_difference":"The decision is probabilistic and request-triggered, not a deterministic cross-service cohort assignment controlled by measured metadata-service headroom; it also lacks explicit urgent classes, per-obligation deadlines, cohort fairness telemetry, and forced queue re-entry."},{"name":"Randomized TTL jitter","source_ids":["SRC3"],"overlap":"Disperses aligned expiry-related backend demand instead of allowing all work to arrive at one boundary.","remaining_difference":"It alters expiration times probabilistically rather than preserving the original validity bound and scheduling required refreshes earlier with capacity feedback, bypass rules, and deadline enforcement."},{"name":"Powered Cache load-aware preloading","source_ids":["SRC4"],"overlap":"Queues and paces cache-generation work, observes live capacity-related load, pauses under pressure, and exposes backlog progress.","remaining_difference":"Its documented automatic trigger follows removal of an expired page; it does not assign deterministic pre-expiry client cohorts, use authoritative metadata-service headroom to advance releases, protect urgent metadata classes, or guarantee item-specific completion before an unchanged expiry."}],"prior_art_disposition":"ADJACENT_PRIOR_ART","contrastive_claim_remaining":"For independently required shared-metadata refreshes, deterministic cross-service cohorts adjusted by authoritative-service headroom can redistribute work within unchanged pre-expiry validity windows while urgent refreshes bypass smoothing and every shifted obligation retains an explicit deadline and forced re-entry path. The retained art establishes early probabilistic refresh, TTL jitter, and load-aware paced preloading, but not that complete control structure.","contrastive_claim_falsifier":"The contrast disappears if an earlier public system combines deterministic pre-expiry cohort assignment, live backing-service capacity control, urgent bypass, unchanged validity bounds, explicit per-item deadlines, and forced re-entry; it also fails empirically if trace replay cannot reduce the original maximum refresh-arrival rate without deadline misses, worse modeled interactive latency, unresolved backlog, or an equal-or-larger secondary peak.","gates":{"adequate_source_search":{"status":"PASS","rationale":"The bounded search covered direct wording, cache-stampede, dogpile, thundering-herd and cache-avalanche terminology, refresh-ahead, TTL jitter, production preloading, live-load throttling, deadlines, and deterministic cohorts. Four opened sources span four publishers and include primary research, official guidance, and first-party implementations.","source_ids":["SRC1","SRC2","SRC3","SRC4"]},"supported_problem":{"status":"PASS","rationale":"Multiple source classes support the causal pattern of aligned expiry producing backend overload, although the exact shared-metadata deployment is only partly supported.","source_ids":["SRC1","SRC2","SRC3"]},"distinct_testable_claim":{"status":"PASS","rationale":"The remaining claim specifies observable structural differences from probabilistic early expiration, TTL jitter, and load-aware preloading and predicts measurable peak, latency, backlog, and deadline outcomes.","source_ids":["SRC1","SRC2","SRC3","SRC4"]},"bounded_next_test":{"status":"PASS","rationale":"A read-only replay of one metadata class over one expiry cycle can compare the unchanged baseline with the proposed shadow cohorts on maximum arrival rate, secondary peaks, modeled interactive latency, backlog, bypasses, and completion before existing deadlines.","source_ids":["SRC1","SRC2","SRC4"]},"no_obvious_safety_or_authority_stop":{"status":"PASS","rationale":"The bounded test changes no production timing or validity rule. Production use would require metadata-, client-, and security-owner approval because early refresh can affect freshness and load-aware pauses can defer work; urgent bypasses, deadlines, halt thresholds, and a kill switch address the obvious concerns without blocking the read-only test.","source_ids":["SRC2","SRC3","SRC4"]}},"screen_survival":true,"world_novelty_boundary":"This bounded public-web screen identifies adjacent prior art and leaves a falsifiable combination claim. It cannot establish world novelty, patentability, market size, expert acceptance, or realized value."}