I'm often encountering systems that are designed for very short queries processing small numbers of rows where the number of connections from the app servers is

I'm often encountering systems that are designed for very short queries processing small numbers of rows where the number of connections from the app servers is configured to be far greater than the number of CPUs. Since those systems are doing very little IO, configuring connection pools to start with much more connections than the DB has CPUs and to add more if the connections are busy (i.e. DB is getting slower, probably because it is highly loaded), is guaranteed to cause resource contention on the DB and escalate the issue in case something goes wrong. Its a total waste and yet the most common configuration in the world.