{
  "slug": "load-aware-hedging",
  "term": "Load-Aware Hedge (LAEDGE)",
  "aliases": [
    "LAEDGE",
    "LÆDGE"
  ],
  "definition": "LAEDGE is a per-shard scheduling policy that sends redundant queries to idle replicas only when no unserved query can use them.",
  "note": "At dispatch, queued first executions take priority over copies; an idle replica otherwise takes the oldest unfinished, unreplicated query. Plain LAEDGE does not cancel running copies. Cleanup cancellation stops a losing copy after completion; preemptive cancellation frees a replica for a new query. [primorac]\n\nThe dispatch-time rule does not guarantee that a running copy never delays later arrivals. Preemptively cancelling the newest copy can discard the one that would finish first. [primorac]",
  "related": [
    "hedged-request",
    "tied-request",
    "adaptive-replica-selection",
    "tail-latency"
  ],
  "citations": [
    {
      "id": "primorac",
      "title": "Primorac, Argyraki and Bugnion. When to Hedge in Interactive Services. NSDI 2021, pp. 373-387; sections 4-6, Algorithm 1.",
      "url": "https://www.usenix.org/system/files/nsdi21-primorac.pdf",
      "accessed": "2026-11-13"
    },
    {
      "id": "hesela",
      "title": "Hesela. Load-aware hedging and the dispatch-time boundary.",
      "url": "https://hesela.com/analyses/storage-tail-slowdowns-raid-fanout/#load-aware-hedging",
      "accessed": "2026-11-13"
    }
  ],
  "status": "research",
  "advantages": [],
  "limitations": [
    {
      "text": "The evaluation concerns in-memory, CPU-bound search; it does not establish a storage-device speedup. A longer scheduler-to-replica round trip can reduce throughput.",
      "citationIds": [
        "primorac"
      ]
    }
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-11-13",
  "provenance": [
    "Full proceedings paper checked, especially Algorithm 1 and sections 4, 5 and 6; simulation and cloud implementation are separate evidence.",
    "No reproduction or hardware experiment; publication year is not a deployment claim."
  ]
}