Random vs keyed partitions
A random partition spreads events evenly, but two events of one user can reach different consumers. A keyed partition sends all events of one user to one consumer, in order. At 1,000 events/s over 8 consumers, random partitions deliver 18,463 events out of order. Keyed partitions deliver none.
13 deliveries · 10 payments applied · 0 charged twice
Case 1
1,000 events/s go to 8 consumers, and each event needs 2 ms of CPU. The events of one user must finish in the order sent. Queue lag must stay below 5 s.
| Measure | Goal | Random partitions | One partition for each user |
|---|---|---|---|
| Out of order | none | 18,463 Fail | 0 Pass |
| Queue lag | under 5 s | 0 s Pass | 0 s Pass |
| Monthly cost | 72 USD/mo | 72 USD/mo | |
| p99 latency | 56 ms | 56 ms | |
| Error rate | 0% | 0% |