Estimate document backlog growth during a provider outage
The design has no answer for how long a backlog takes to drain after the parser is unavailable for an hour.
- Focused work estimate
- 5h + prerequisites
- Priority in the scenario
- Medium
- Engineering practice
- Queueing · Capacity planning
Estimated field mix
- Performance engineering50%
- System design30%
- Site reliability20%
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 procurement portal extracts metadata from uploaded documents. Product wants a responsive upload flow; security wants parser failures isolated from customer-facing processes.
Setup prerequisites
- Create synthetic upload metadata and a fake processing provider.
- Treat diagrams as proposals; implement only local contract probes.
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
- ABOUND-101 · Translate document-processing expectations into a bounded workload model
- ABOUND-102 · Draw the document trust boundary with authoritative state owners
- ABOUND-103 · Write the decision record for direct-to-storage document upload
- ABOUND-104 · Specify a document lifecycle that survives parser retries
- ABOUND-105 · Design the transactional dispatch contract for extraction work
- ABOUND-106 · Define extraction-provider deadlines and uncertain completion semantics
Acceptance criteria
- Calculate arrivals, stored bytes and queued work during outage.
- Model recovery with explicit service-time and concurrency assumptions.
- Identify when admission must slow or stop.
Implementation constraints
- Use a spreadsheet or executable script with hypothetical values, not invented measurements.
Verification to include
- Calculate backlog for the declared baseline assumptions.
- Increase arrival rate above recovery capacity and show the queue does not drain.
Deliverables
- Capacity model and outage sensitivity script
Rollout and recovery
Use the model to set a reviewed admission proposal; revise with real measurements before production sizing.
Value of the work
For the engineer: Practice boundary decisions backed by executable consistency and failure checks.
For the team: Review architecture tradeoffs with explicit assumptions before infrastructure commitment.
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.