Recovering problems with change function and throttling preprocessing

[iprok]

Hello! I have trigger with function "change(/StorageAlpha/smart.disk.attribute.reallocated_sector_ct[sdw sat])>0" the item used has "Discard if unchanged with heartbeet (6h)" preprocessing and 1m interval. The trigger with "OK event generation" set to "Expression" worked as expected closing the problems in >= 6h hours. I had supposed that using "nodata(/StorageAlpha/smart.disk.attribute.reallocated_sector_ct[sdw sat],5m)=1" will close the trigger in 5m in case of no further changes. But it closes in 6h5m usually and sometimes (rarely) in even more time. And I stopped understanding its logic completely.

Please explain how nodata works with the throttling rule and why it works as described and my situation? And is it possible to close it quicker that 6h without changing throttling rule?

[cyber]

change>0 works only if your values are growing. It is not a 0|1 answer, changed|not changed, it is a amount of difference... thus >0 must be a positive number... if it goes 1->0, change is -1. You can use "abs" funtion to make it non-negative. Then each change can be calculated with >0 (abs(change(/host/item))>0

trigger can be caclulated only if there is a incoming value. if you discard item values for 6h, there can be no trigger calculation.