ReferenceGlossary
GC pause
Time when a garbage collector stops or slows the application to find and free memory that is no longer used. Pauses usually hit only some requests, so they show up in tail latency, such as the p99, more than in the average.
Runtimes
In Quorum#
When an App Server's heap is more than 70% full, its collector pauses up to 2% of requests. Java pauses 30 ms with G1, 150 ms with Parallel, or 1 ms with ZGC, which costs 10% of throughput and 15% more memory. Go pauses only 1 ms but spends up to 25% more CPU, which Go GC tuning trades against memory. In the GC pause storm Incident the heap fills further and 5× as many requests pause.
Read next#
Memory leak, Percentile (p50, p95, p99), Tail at scale, JIT warmup