I have mapdb configured to persist all Items, along with restoreOnStartup. I have some temperature sensors that occasionally fail, so I’m using the Expire binding to set these Items to UNDEF if they don’t receive an update at their expected interval (this avoids having erroneous values showing in s…

This isn’t overly helpful but why don’t you fix the sensors? If it were me, I would put the effort there instead of compensating for their failure. To me, an unreliable sensor is not worth having. Your projected dummy value and rule is definitely an option. Why not simply not restore it on start…

I agree, this is a case where it makes no sense to restoreOnStartup. Beyond that, you can create a System started rule and postUpdate the restored state to those items which will reset the expire binding.

Thanks both for your replies. @Moxified Oh absolutely I’ll fix the sensors, I just want to ensure I gracefully handle any failure that may occur in the future. One of the reasons I’m doing this is to more easily spot if/when they do fail (battery exhaustion usually). Using UNDEF seems to work very…

What type of sensor is it? Can you use some form of heartbeat on it such as network monitor if it is ip based?

[image] AlexForrow: I wonder if that rule could go further than that and check lastUpdate itself to avoid waiting for the Expire binding to trigger. You can do pretty much anything you want to. [image] AlexForrow: Do you know of a better way of doing this, generally? I would not resto…

The sensor in question is an Jeenode board sending data into OpenHAB via the Serial binding, but I was planning to apply the same principles to various Z-Wave Fibaro sensors. I figured the great thing about checking the value is up to date is that it would detect various kinds of failure.

[image] rlkoshak: I would not restoreOnStartup. You already have to deal with the fact that the Items might be NULL at some point, so I would leave them as NULL until you get a valid reading. This ensures that you are not acting on stale and incorrect data. When the Item has a value you know th…

[image] AlexForrow: I figured the great thing about checking the value is up to date is that it would detect various kinds of failure. Absolutely. If you need to generate an alert or suchlike, it should work to put all relevant Items in a Group with an OR aggregation. A rule can watch for …

Mapdb: storing UNDEF or NULL

Add-ons Persistence Services

AlexForrow (Alex Forrow) January 12, 2018, 10:33pm 8

Ok cool I’ll give this a go. Thanks!

Automatic lighting control without timers