This task is a continuation of ZBXNEXT-98 and is meant to deal with new challenges that were brought up by its implementation.

We currently use two strategies for spreading items in time: based on item ID and based on interface ID (for JMX items (since ZBXNEXT-555), for SNMP items (since ZBXNEXT-98) and for ICMP pings (since ZBX-7649)).

This is good and should work in most cases. However, in case of SNMP, with large switches like Cisco Nexus 9000 with hundreds and thousands of ports, there can be hundreds of thousands of items on a single host. Querying all these hundreds of thousands at the same time is not ideal.

So scheduling should be improved and currently two approaches were thought of.

One is to schedule items based on "itemid - itemid % modulo", where "modulo" is small for interfaces with few items and large for interfaces with a large number of items.

Another is to specify in the server configuration file how many pollers can process items for a single interface. For instance, at most 5 pollers per interface, so that hundreds of pollers do not assault a single device.