The worst pain comes from falling in the same hole twice.
When you do the work to solve a performance problem, it is often a good idea to add meters in your ongoing, always-running set of meters, to watch for the return of that problem.
Remember the line from Casablanca? “Round up the usual suspects.“ It is often the case that what caused the previous performance problem is the first thing blamed for the next one. Every minute spent working on the wrong problem is wasted time and lost opportunity. Having that extra meter running can help you quickly determine if the same old problem is back, or there is a new mystery to solve.