obviously the connector cannot handle aggregations. Direct Discovery is a feature which uses SQL aggregation queries only which consists of a GROUP BY clause and aggregation functions (count/min/max/sum/avg etc. for charts).
Usually this functionality is only provided by a real database. I wonder if you're going to implement this in a connector..
The reason I would like to use my own custom connector is that I don't the Qlikview to be soliciting my database whenever the user selection changes.
Also, because of the size of the data I need to pull, I would like to be able to stream it during run time so that it is not loaded in-memory all at once.
To address this problem I was thinking about creating my own datastore and use a custom connector to query it and stream it back to Qlikview.