Besides what Phil mentioned below, I can't write more than one record to the WAL. You're closing the file after every write, the second time you write the error `seek data/rebuf.tmp: file already closed` is returned.
I also think your rotation will delete the wrong segment when you have more than ten segments - imagine you're writing rebuf-1 to rebuf-10 - what's the "oldest file" to delete now? Besides, should you really delete those files?
I also think your rotation will delete the wrong segment when you have more than ten segments - imagine you're writing rebuf-1 to rebuf-10 - what's the "oldest file" to delete now? Besides, should you really delete those files?