I just update my Zabbix frontend from 3.2 to 4.0.0 and noticed that it became much slower.

I enabled "debug mode" in 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, so this is an almost fresh database (with old hosts, templates, etc...). I wonder why it's so slow now?