I just upgraded my zabbix server and frontend to 4.0.0 and noticed that the frontend became much much slower.

I enabled "debug mode" for my admin user and here is what it shows:

******************** Script profiler ********************
Total time: 3.977146
Total SQL time: 0.026631
SQL count: 30 (selects: 20 | executes: 10)
Peak memory usage: 4.5M
Memory limit: 2147483648

I removed all the historical data and trends before the upgrade, so this is an almost fresh database, so it's definitely not SQL related.

All my websites load within 50ms, so I wonder what's wrong with the new frontend that it takes almost 4 seconds to process almost none data?