1.7 and 1.71

When I use piwik 1.7, MYSQL database connection number can achieve 200 or so, but cause the system to very slow. today I upgrade to piwik 1.71, the system became faster, but the database connection number becomes very smaller, maximum only 38. Why?

Because we fixed a performance issue in 1.7.1: Performance regression in tracker for high traffic website · Issue #2944 · matomo-org/matomo · GitHub