hysteresis - why does it work?

[globifrosch]

example from manual 4.13.4.Hysteresis:

({TRIGGER.VALUE}=0&{server:temp.last(0)}>20)|
({TRIGGER.VALUE}=1&{server:temp.last(0)}>15)


manual 4.3.1 List of supported macros:
TRIGGER.VALUE
0 - trigger is in OFF state
1 – trigger is in ON state
2 – trigger UNKNOWN

so... if i read the example, my understanding is that it won't trigger because a newly created trigger is in state UNKNOWN (2)?

- Thomas

[Alexei]

example from manual 4.13.4.Hysteresis:

({TRIGGER.VALUE}=0&{server:temp.last(0)}>20)|
({TRIGGER.VALUE}=1&{server:temp.last(0)}>15)


manual 4.3.1 List of supported macros:
TRIGGER.VALUE
0 - trigger is in OFF state
1 – trigger is in ON state
2 – trigger UNKNOWN

so... if i read the example, my understanding is that it won't trigger because a newly created trigger is in state UNKNOWN (2)?

- Thomas

I think you are right. First received value will make this trigger OFF, only next value could switch it to the ON (PROBLEM) state.

[globifrosch]

I think you are right. First received value will make this trigger OFF, only next value could switch it to the ON (PROBLEM) state.

ah ok, it won't trigger on the first, but will do on later values.

so maybe this would trigger on the first :

({TRIGGER.VALUE}#1&{server:temp.last(0)}>20)|
({TRIGGER.VALUE}=1&{server:temp.last(0)}>15)

[Alexei]

ah ok, it won't trigger on the first, but will do on later values.

so maybe this would trigger on the first :

({TRIGGER.VALUE}#1&{server:temp.last(0)}>20)|
({TRIGGER.VALUE}=1&{server:temp.last(0)}>15)

It is not quite correct, as there could be cases like:

TRUE->UNKNOWN->TRUE
and
FALSE->UNKNOWN->FALSE

For example, after Zabbix server restart.