> ## Documentation Index
> Fetch the complete documentation index at: https://docs.breakscale.tech/llms.txt
> Use this file to discover all available pages before exploring further.

# Cache aside

> What happens when the hit rate falls

The cache absorbs most reads. Lower the hit rate and the database takes the whole load.

## What to watch

The database only ever sees the misses. At an 85 percent hit rate it takes about 30 requests a second out of 200. Drag the hit rate down to 0.3 and it is instantly over its 133 a second ceiling, with no change in load at all.

## What it is made of

| Component | Count |
| --------- | ----: |
| Cache     |     1 |
| Client    |     1 |
| Database  |     1 |
| Service   |     1 |

## Under load

Measured by running this design through the simulator at multiples of its own offered rate of 200 requests a second. Twenty seconds of simulated time, one fixed seed, so the same numbers come out every time.

<Note>This design holds 800 requests a second with 0% errors. At 1200 it is losing 3% of them.</Note>

| Offered | Goodput |     p99 | Errors |
| ------: | ------: | ------: | -----: |
|     200 |     204 |  61.9ms |     0% |
|     300 |     302 |  73.9ms |     0% |
|     400 |     417 |  80.3ms |     0% |
|     500 |     522 | 108.6ms |     0% |
|     600 |     633 |  95.6ms |     0% |
|     800 |     820 | 143.6ms |     0% |
|    1200 |    1066 | 313.8ms |   3.2% |
|    1600 |    1520 | 320.7ms |   8.1% |

<Card title="Open this example" icon="play" href="https://breakscale.tech">
  Load **Cache aside** from the Examples menu and drag the traffic slider yourself.
</Card>