We use a ScrollableResultsImpl to stream big search results to the client instead of fetching them in one go. The ScrollableResultsImpl keeps a window of data so you can scroll forth and back, but does not clean out data outside of the window. This leads to OutOfmemory exceptions in our use case. I have patched the ScrollableResultsImpl in our environment to clean out all data not in the current window, which fixes the problem for us.