graph: show "significant figures" instead of decimal places

[matthiasr]

• What Grafana version are you using?
  4.3.2

• What datasource are you using?
  Prometheus

• What OS are you running grafana on?
  Linux

• What did you do?
  Created a single-stat with € unit, specified "2 decimals" precision

• What was the expected result?
  €1.2K or €1200, €460

• What happened instead?
  €1.23K, €456.78

The shortening of the value (1K instead of 1000) makes this even more confusing, but as a feature I would also like this for un-shortened numbers. Sometimes a number is known not to be exact and I'd rather only display a certain number of significant figures. Currently, I can only specify "decimals" (right of the point) while significant figures might already end left of the point.

For shortened units this is even worse because the precision implied varies wildly (plus/minus 3 figures).

This could either replace the Decimals or be an additional option.

[marcelgsteiger]

This or a similar feature is especially helpful for displaying counters, e.g. energy counters.

One thing that could perhaps be done easily, is prohibiting the automatic conversion of units to K, M, G... some way. To begin, one could stop the conversion as soon as zero decimal places have been specified. For example:
if I specify Watt as units with 0 decimal places, 1100 W will remain this way and never convert to 1 kW; whereas if I specify one decimal place, it will be displayed as it does currently (as 1.1 kW) .

This way we could alleviate the problem without introducing a completely new feature.

Zabbix (which I use as a backend to grafana) has the following solution to this problem: It allows to specify the unit with a modifier. Example: If I define the unit as dWh (deciwatthours), it will convert to Wh, kWh, MWh etc. as usual. However, if I prepend the unit with an exclamation mark ( !dWh ) it will always be shown as dWh. For energy counters, this is very helpful: I have energy counters with a 1 dWh resolution and want to display the exact value. In a diagram with a counter starting at about 1.75 MWh on the y-axis it looks like this:

Sorry, some numbers are cut off from the graphic, but the idea can be seen. Zabbix is less than perfect in rendering graphic, this is why I prefer Grafana...

#38493 was my original post about this. It would be nice if we could do something like this in grafana, too. So I add my suggestion here.

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This issue has been automatically closed because it has not had any further activity in the last 30 days. Thank you for your contributions!