See https://www.zabbix.org/wiki/Docs/specs/ZBXNEXT-1574 for detailed specification.
Start Zabbix server process is slow for a lot of triggers
ERROR [file:db.c,line:1582] Something impossible has just happened
don't show triggers that haven't changed state if expression is changed
Update ids loop
Faster trigger update on startup
The "show unknown events" checkbox on the events monitoring page
Server has long startup times when the database server is 10ms away