Double entry
Difficulty 2 of 5
Each transfer posts a debit and a credit that sum to zero in the ledger, 400 transfers/s. The wallet reads 8,000 balances/s through a cache that keeps entries for 300 s. Balance reads must match the ledger. Keep mismatched reads below 2,500.
Outbox · 10 orders · 10 events · 0 lost
Goals and limits
- Data mismatches (Balances)
- under 2,500
- p99 latency (Balances)
- under 50 ms
- Error rate (Balances)
- under 0.1%
- Monthly cost
- under 40 USD/mo
- Parts you can add
- Change capture, Managed pub/sub, Redis cache, Postgres
- Part limit
- 8
- Traffic
- 8,000 req/s
Concepts
How players did
Player results load from the server.