Easy to measure, sure, but that's different than impact on performance. You're much more likely to get a bigger win from analyzing database schema, divide-and-

Easy to measure, sure, but that's different than impact on performance. You're much more likely to get a bigger win from analyzing database schema, divide-and-conquering the workload, tuning the algorithms in the critical path, or even choosing _what_ gets cached. If tuning the cache eviction is the main thing it is probably because that's the only thing.