Zabbix server health template should include the newly introduced metric: zabbix[preprocessing], which provides stats of the preprocessing manager:

• queued - the number and size of queued values that require preprocessing (counter)
• direct - the number and size of values that did not require preprocessing (counter)
• queue - The count of values enqueued in the preprocessing queue (same as zabbix[preprocessing_queue])

JSON:

{
        "queued": {
                "count": 0,
                "size": 0
        },
        "direct": {
                "count": 0,
                "size": 0
        },
        "queue": 0
}