Measure assignment lock behavior without claiming a throughput guarantee
Operators need to choose a polling interval and concurrency limit based on observed contention in the local prototype.
- Focused work estimate
- 3h + prerequisites
- Priority in the scenario
- Medium
- Engineering practice
- Database observability · Concurrency testing
Estimated field mix
- Database engineering50%
- Performance engineering30%
- Quality engineering20%
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
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Project context
A fictional inspection service assigns review jobs to staff. Polling clients sometimes claim the same job and a disconnected client can finish work after reassignment.
Setup prerequisites
- Create synthetic jobs and two independent database clients.
- Use explicit state methods and an injected clock.
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
- ACLAIM-101 · Define assignment states and their required database fields
- ACLAIM-102 · Order eligible jobs with a stable tie break
- ACLAIM-103 · Scope work assignment queries to the operator's organization
- ACLAIM-104 · Claim one pending job atomically under competing pollers
- ACLAIM-105 · Issue a monotonically increasing assignment generation on every reclaim
- ACLAIM-106 · Renew assignment leases without extending a completed job
- ACLAIM-107 · Finish a job and publish its result reference in one transaction
- ACLAIM-108 · Reclaim expired assignments using current row authority
Acceptance criteria
- Record database/runtime versions and synthetic job count.
- Measure lock waits and claim outcomes at fixed concurrency levels.
- Keep correctness assertions enabled during every run.
Implementation constraints
- Repeat each local condition three times; results describe only that environment.
Verification to include
- Run identical workloads at one and four pollers and record observations.
- Hold a long transaction and verify timeouts remain bounded without duplicate claims.
Deliverables
- Contention probe and observation report
Rollout and recovery
Use observations to propose conservative local limits; restore lower concurrency if claim failures rise.
Value of the work
For the engineer: Practice database concurrency, leases and transactional invariants.
For the team: Review whether assignment authority remains reliable during contention and recovery.
Evidence boundaries
Outcome Evidence: Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs.
Ownership Evidence: Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence.