RSM

.......PS. [ZBXNEXT-4732] new server side changes for ZBXNEXT-4131

- Caching templates and templated items.
- Gathering items involved in trigger expression (expression.c),
  and using them to gather tags (trigger.c).
- For each item involved in event, recursively traversing now cached template tree to find (host/template)
  where the item was defined. Gathering tags from that host. (dbconfig.c)