Architecture & practice·Judgement and reasoning traps
latency and CPU rose together and you spent two hours on the CPU, which was a symptom of the same queue.
Correlation is not causation
Also calledspurious correlation
Two things moving together does not establish that one moved the other. In incidents this is the most expensive reasoning error available, because dashboards are full of correlated metrics and the compelling one is often downstream of the real cause. The way out is a mechanism: say out loud how A would cause B, and if you cannot, treat the correlation as a clue rather than as a conclusion.