An hourly spike that made every request four hundred milliseconds slower for two seconds moved the average by nine milliseconds and was invisible in every graph anyone looks…
7.0 changed the default primary shard count from five to one, which is a considerable behavioural change hidden in a release note. The old default was widely agreed…
A tool firing requests as fast as it can with no pause measures how quickly the server can be saturated, which corresponds to no real number of users.…
Memoising a callback stops it changing identity between renders, which only matters if something downstream is comparing identities — and by default nothing is. The two have to…
An instrumenting profiler records every function call, which changes the timings it is measuring — small fast functions look disproportionately expensive because the overhead is per call. Sampling…
Caching Composer or npm downloads previously meant a layer holding the cache directory, which bloats the image and is invalidated whenever anything above it changes. The cache lives…