Missing keys

  • Fix
  • Cache 13

Difficulty 2 of 5

Of all lookups, 99 percent ask for IDs that do not exist. Normal cache entries do not stop these reads from reaching the source. Keep source CPU below 70 percent and p99 below 150 ms.

0:00. Source CPU is far above 70 percent. Graph: cache misses are almost equal to total lookups.

Play level

HTTP/2SQLUsers5,000 req/sRedis cache0.25 vCPU · 0.5 GBPostgres0.5 vCPU · 1 GB
HTTP/2SQLUsers5,000 req/sRedis cache0.25 vCPU · 0.5 GBPostgres0.5 vCPU · 1 GB
The board at the start of the level
Cache size and hit ratioDrag or use arrow keys to change the cache size

1,600 keys · hit 81% · mean 3.2 ms

Goals and limits

p99 latency
under 150 ms
CPU use
under 70%
Monthly cost
under 30 USD/mo
Parts you can add
Redis cache
Part limit
16
Edit limit
3
Traffic
5,000 req/s

Concepts

How players did

Player results load from the server.

All levels