I just ran into something similar to this too. On our test setup we're naming files by the hour. The last rolled file for each hour isn't getting closed properly, with the name still being xyz-timestamp.tmp(I guess it eventually will once we hit a file limit? I think there was some code floating about to limit the number of open files, closing the oldest as necessary)
Any thoughts on how to decide when to roll? Add a configuration for a fileroller, allowing configuration for how long it waits till closing inactive files?