Hedged requests

  • Tune
  • Scale 16

Difficulty 4 of 5

One of 16 replicas answers 200 ms late. After the timeout, the client sends the request again to the pool, up to 2 times. Tune the timeout. Keep p99 under 100 ms, errors under 0.1 percent and CPU use under 56 percent.

Play level

HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2Users3,200 req/sLoad balanc…2 vCPU · 2 GBNode API2 vCPU · 2 GBNode API2 vCPU · 2 GBNode API2 vCPU · 2 GBNode API2 vCPU · 2 GBNode API2 vCPU · 2 GBNode API2 vCPU · 2 GBNode API2 vCPU · 2 GBNode API2 vCPU · 2 GBNode API2 vCPU · 2 GBNode API2 vCPU · 2 GBNode API2 vCPU · 2 GBNode API2 vCPU · 2 GBNode API2 vCPU · 2 GBNode API2 vCPU · 2 GBNode API2 vCPU · 2 GBNode API2 vCPU · 2 GB
HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2HTTP/2UsersLoad…Node…Node…Node…Node…Node…Node…Node…Node…Node…Node…Node…Node…Node…Node…Node…Node…
The board at the start of the level
A page waits for its slowest callDrag or use arrow keys to change the calls per page

Calls per page: 20 · 18% of pages wait 2.0 s

Goals and limits

p99 latency
under 100 ms
Error rate
under 0.1%
CPU use
under 56%
Monthly cost
under 200 USD/mo
Traffic
3,200 req/s

Concepts

How players did

Player results load from the server.

All levels