Steps to reproduce:

1. Zabbix 4.0/4.4 with 0.5TB history and 0.1TB trends with partitioning (MySQL/Percona/MariaDB);
2. use zabbix_sender/zabbix trapper to gather history from file with timestamps;
3. send unixtime value equal 0;

Result:

1. history syncer stuck doing query:

   select distinct itemid from trends where clock>=0 and itemid in (<very long list of itemids>)
   

2. MySQL-based DB does not provide global index on partitioned tables - this means full scan for all 365 partitions (trends) due to the requirement get data starting from clock equal 0 even if local indexes are presented for table;

Problems:

1. in case of a database partitioning any query trying to get values from the first partition to the last will cause full scan without index;
2. data with unixtime 0 or out of the defined range useless;

Expected:

1. trends should be recalculated only within defined period of time;
2. drop/not accept history values for the not defined history/trends periods of time;
3. if possible avoid full scan queries for trends re-calculation in case partitioning is used;