I bump version numbers when I patch. If you want to jump to some arbitrary high version number(s) just so those e2 guys know that our stuff is better than theirs, then feel free to apply such a patch. (:

Leaving the file open complicates rotating the log. I don't know how the log is currently rotated, but for the minor price of writing a log line (which shouldn't take long at all) being about 3 times as slow (according to your benchmarks), I'd rather stick with the open/close cycle so that whatever rotation scheme is in place works.

Eliminating nearly all of the open/close'ing would be fine if we go with a log rotation scheme that restarts apache after the log file is rotated such that the time during which log lines could go to either file is minimized.