Hi!

We have an app that we want to run on the edge platform. In the app, there is a graph visualization of data where the user can choose which variable to show, with to and from date. 

When I use the API:

/DataService/Data/variableID

The return shows data from every second like this:

The maximum length of points is 2000, so in the end, i get this:

The problem is: If the user want to visualize an entire month, the API will return every datapoint from every second the data has changed. As far as I see, there is no way to choose the "resolution", so for example 1 property every hour, 1 property every day etc.

Of course, this is possible to filter out in code, but I am worried that I would spam the API, as there probably is a limit to how many calls you can make each minute?

Has anyone worked around this before?

Hi,

in order to reduce the need for big data requests there is one think you can do that I know of. In the Data Service it is possible to create aggregations which are pre-calculated. For example you want a mean temperature in an hourly cycle which otherwise gets checked every second. This would reduce the requested data by a factor of 3600. 

In order to create this pre-calculated aggregation you have to open the DataService UI and edit the variable under the aggregation tab. Of course this is not a dynamic solution but might already help you. You can find further information in the Data Service documentation v1.6 under "8.1 adding a variable"

Hi,

for your Use Case the Data Service offers the /calculateTrend API. When calling this API you can define which aggregation (min, max, avg. etc.) should be applied, the aggregation cycle and the timespan you want to get the data for.

Example Body

As this is calculated on demand this can be to slow for your requirements. For that you can create a pre-calculate aggregation. Either you configure that in the UI or as well use the API for that. For creating calculations the Data Service offers the /aggregations API. After you created the API you can call as well the /calculateTrend API. When calling this the pre calculated aggregation is then used to accelerate the request.