Flow results should be deleted after a time period if there has not been an acknowledgement to delete them already. This will save disc space for results that are not going to be retrieved by the client.
The default time period to delete the results should be sufficiently long enough (say 30 days for example). The time period should also be configurable via the node configuration.
Check if flows are running, if there are not then this would be a good time to delete checkpoints so they don't collide with running statements from flows
This should include the deletion of failed flows as well