Sheet 11

DLQ, Retry Topics & Reprocessing Logic

4-tier exponential backoff schedule, failure probability modeling, dead-letter storage, and drain throughput.

Daily DLQ Messages1,782,060 msgs/day (2.97%)

Exponential Retry Tier Progression

Tier 15s

5s delay

order.retry.5s

Transient network glitch

Tier 215s

10s delay

order.retry.30s

Database connection blip

Tier 335s

20s delay

order.retry.5m

Downstream payment timeout

Tier 475s

40s delay

order.retry.40s

Final automated attempt

Dead-Letter75s+

Indefinite delay

order.dlq

Route to DLQ for manual inspection

Batch Reprocessing Capacity

Reprocess Batch Size1,000 msgs

Reprocess Workers4 Worker Threads

Throughput Rate267 msgs/min

Full 24h Drain Time111.4 hours

Preserved Dead-Letter JSON Envelope

{
  "event_id": "evt_99824bf201",
  "topic": "order.events",
  "failed_at": "2026-09-10T14:32:10.451Z",
  "error_code": "PAYMENT_GATEWAY_TIMEOUT",
  "retry_count": 4,
  "original_payload": {
    "order_id": "ord_1002931",
    "user_id": "usr_882194",
    "amount_cents": 8990,
    "currency": "USD",
    "idempotency_key": "idem_9a87f4c2"
  },
  "error_stack": "TimeoutError: Gateway did not respond within 3000ms after 4 retries"
}