Exceeding the limit of limited private memory

We have a terrible experience with gae go. When our application was free, we never had a problem limiting the excess of soft private memory . We reached the quota, so we decided to pay. Our daily budget is $ 3. After activating the paid service, we were again able to use the site, and the quota was exceeded. After a few hours, we got the Exceeding Soft Private Memory restriction and could no longer see anything but this. I tried to clear some big data in the data warehouse, disable embedded attachments and still have no luck.

I did some tests in the code where the error occurs. After removing the access code for the data warehouse, create the site again. Thus, my conclusion is that access to the data warehouse, even to get very few objects, would cause an error like this. We are a little hopeless. We decided to use appspot to use the technology, but we get this because we cannot move on to development.

Below is the code that causes this error.

q := datastore.NewQuery("Course")
    courses := make([]courseData, 0)
    if keys, err := q.GetAll(c, &courses); err != nil {
        http.Error(w, err.Error(), http.StatusInternalServerError)
        return
    } else {
      for i := range courses {                 
          courses[i].Key = keys[i]
      }                           
    }

Any help you could extend for us would be greatly appreciated. Thank you in advance.