Hello,
We`ve got problem with restarting zabbix-server and it`s database operations.
During restarting of zabbix-server executed query:
"select max(id) from history_log where id between 0 and 9223372036854775807"
That caused to heavy load on database and 3-hour delay of starting service. The service is waiting for ending of that query, and starts only after parsing all data. Database size is 5Tb running on PostgreSQL 9.5