Upthread [0], you can find some notes and an explanation from one of the devs that they actively work around the GC, because the approach it uses just... Doesn't work for this kind of workload.
> This percentage can be configured by the GOGC environment variable or by calling debug.SetGCPercent. The default value is 100, which means that GC is triggered when the freshly allocated data is equal to the amount of live data at the end of the last collection period. This generally works well in practice, but the Pebble Block Cache is often configured to be 10s of gigabytes in size. Waiting for 10s of gigabytes of data to be allocated before triggering a GC results in very large Go heap sizes.
> This percentage can be configured by the GOGC environment variable or by calling debug.SetGCPercent. The default value is 100, which means that GC is triggered when the freshly allocated data is equal to the amount of live data at the end of the last collection period. This generally works well in practice, but the Pebble Block Cache is often configured to be 10s of gigabytes in size. Waiting for 10s of gigabytes of data to be allocated before triggering a GC results in very large Go heap sizes.
[0] https://news.ycombinator.com/item?id=24485931