A table sorted by inclusive time puts the entry point at the top and tells you nothing; sorted by exclusive time it hides the structure. The graph shows…
8.0 went GA in April and the correlated subquery can retire. The plans before and after, the recursive CTE that replaces a loop, and the upgrade nobody expects.
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…
Guessing what is large in a bundle is unreliable, and the answer is frequently one dependency that pulled in a locale file for every language on earth. The…
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…
A single profile tells you where the time goes and leaves the question of whether that is unusual. A comparison between two profiles answers the question you actually…
A 400ms pause on every request, once an hour, caused by a cache cleanup nobody thought of as expensive. Redis is single-threaded, and freeing memory is work.