Groupwise recording time of events

Hello,

I do my event-recordings to an external SQL-server.
In recorder it is possible to generally increase or decrease purging-time.
And so - by what I found out - after a couple of days I have no more access to my energy consumption data. However, this data and the value I have from it lives from a long storage time, so that I can compare my energy consumption a year ago with the current.
On the other hand I can cope with a short storage time for events like light turn off or on or opening doors.

It would therefore be nice to have event-groups that can be stored for a certain different duration.
Or maybe some data like energy data could be stored with less datapoints after purging to reduce space.