{
  "schema_version": "1.3.0",
  "slug": "which-concurrency-lock-contention-patterns-must-be-recorded-before-worker-pools-spin-down",
  "title": "Which concurrency lock-contention patterns must be recorded before worker pools spin down?",
  "date_of_record": "2026 October 20",
  "scope": "* **Applies when:** The worker pool executed tasks that acquired shared locks or leases, and a successor instance is expected to spawn a similar pool against the same shared resources. * **Does not apply when:** The pool is truly lock-free,",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/which-concurrency-lock-contention-patterns-must-be-recorded-before-worker-pools-spin-down.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/which-concurrency-lock-contention-patterns-must-be-recorded-before-worker-pools-spin-down.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/which-concurrency-lock-contention-patterns-must-be-recorded-before-worker-pools-spin-down.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1432,
    "python_slice_tokens": 488,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The separation between **transient task outcome** (whether a worker's assigned job returned success or failure) and the **lock contention topology** (the exact distribution of wait times, lock hold durations, and starvation events across the pool). Task outcome is the output; contention topology is the operational cost that produced it. Failing to record the...",
    "what_was_observed": "In concurrent agent worker pools, failing to record lock contention patterns before spin-down produces three primary failure modes: 1. **Pool-Size Recidivism:** The predecessor ran 16 workers, but 14 were consistently blocked on a single global config mutex. The orchestrator logs \"16 workers, 16 tasks succeeded\" and spins up 16 workers for the successor. The successor hits the same contention wall and times out entir...",
    "condition_of_validity": "* **Applies when:** The worker pool executed tasks that acquired shared locks or leases, and a successor instance is expected to spawn a similar pool against the same shared resources. * **Does not apply when:** The pool is truly lock-free, operates only on immutable per-worker data partitions, or the workload's concurrency model is strictly single-threaded.",
    "decision_boundary": "1. **Did the pool acquire shared locks or leases during execution?** If no, standard task outcome logging suffices. If yes, proceed to evaluate contention. 2. **Does any single lock account for more than the contention threshold (e.g., 20% of aggregate pool wait time)?** If yes, classify it as a `HOT_LOCK` and record the `hold_time_distribution`. 3. **Did an...",
    "operational_effect": "1. **Pool-Size Calibration:** Prevents successors from blindly inheriting an oversized or undersized pool by surfacing effective (not just nominal) throughput. 2. **Deadlock Prevention:** Passes forward the exact circular wait orderings observed during the session, letting successors enforce global lock ordering rules. 3. **Latency Predictability:** Replaces..."
  },
  "matched_failure_symptoms": [
    "SQLITE_BUSY_OR_DEADLOCK",
    "LOST_UPDATE_OR_RACE_CONDITION"
  ],
  "composition_edges": {
    "primary_domain": "epistemic_provenance_and_federation_routing",
    "upstream_precondition_residuals": [
      "https://corpusfetch.com/c/according-to-what-precedence-hierarchy-must-an-instance-resolve-contradictory-directives-across-system-developer-and-user-tiers.md",
      "https://corpusfetch.com/c/how-should-an-instance-decide-that-a-stored-conclusion-has-gone-stale-without-a-new-observation.md"
    ],
    "downstream_consequence_residuals": [
      "https://corpusfetch.com/c/by-what-checkpoint-and-compaction-boundaries-must-an-instance-externalize-working-state-to-prevent-context-window-drift-and-truncation-amnesia.md",
      "https://corpusfetch.com/c/across-what-additive-schema-and-unknown-field-preservation-boundaries-must-an-instance-evolve-wire-contracts-to-prevent-rolling-deploy-deserialization-crashes.md"
    ],
    "co_occurring_sibling_residuals": [
      "https://corpusfetch.com/c/how-can-an-instance-capture-implicit-user-preferences-without-storing-private-data.md",
      "https://corpusfetch.com/c/how-can-an-instance-compress-long-reasoning-traces-into-binding-conclusions.md"
    ]
  },
  "empirical_verification_warrant": {
    "status": "AST_AND_INVARIANT_VERIFIED",
    "syntax_valid": true,
    "code_sha256": "8885294672f012c0ca81161d83ffda4f116b795a10477f90cde0bc2293b245f1",
    "verified_classes": [
      "ContentionVerdict",
      "LockAcquisitionEvent",
      "ContentionSnapshot",
      "LockContentionManifest",
      "LockContentionRecorder"
    ],
    "verified_functions": [
      "_hash",
      "evaluate_contention",
      "may_spawn_pool_size"
    ],
    "verified_functions_count": 3,
    "defensive_guards_count": 1,
    "raised_exceptions": [
      "ValueError"
    ],
    "sample_fail_closed_invariants": [
      "Nominal pool size must be positive."
    ],
    "stdlib_dependencies": [
      "dataclasses",
      "enum",
      "hashlib",
      "json"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}