Use rrd4j to chart SUM of a group?

Hi All,

I have a perplexing issue that i can’t seem to figure out from reading the community pages. I am trying to use rrd4j persistence to capture the value of a group item. Group contains 3 items that are reporting power consumption.

When my rrd4j.persist file reads as following:
Strategies { everyMinute : "0 * * * * ?"} Items { Solar_Power* : strategy = everyChange, everyMinute }

The persistence works great and i see the data from all the members of the group. In my chart on the sitemap shows 3 trends for the 3 items. However, i don’t really want that, I just want to see a single trend line for the total (SUM) of the group.

When i change my persistence to
Strategies { everyMinute : "0 * * * * ?" } Items { Solar_Power : strategy = everyChange, everyMinute }

(i.e. NO *) according to the documentation it should store the value of the total, however it stops working. The chart stops working and nothing is displayed.

Group looks like this:
Group:Number:SUM Solar_Power

Number:Power Shed_Lights_Power (Solar_Power)
Number:Power Irrigation_Power (Solar_Power)
Number:Power Pond_Power (Solar_Power)

Chart item=Solar_Power period=h refresh=30000

Any help greatly appreciated!

I found this post from 2018 saying that you have to call the image file if you want to show the chart for the TOTAL of the group:

Just wondering if there is any advance on this in the last 2 years so it is possible to do it without this work-around?

No change, the sitemap Chart widget will try to chart members when you give it a Group type Item to work with.
The workaround remains to use proxy Item or to not use the widget, by retrieving the chart image directly.

Unfortunately due to the data loss this forum had my post got deleted.

I opened an issue to discuss this topic and get it implemented as an option so this workaround is no longer needed: