[Zope-CMF] [Explanation] really slow CMF

[Dieter Maurer]

We are currently releasing a professional site based on CMF.

Unfortunately, it was really slow. Even the simplest request
took 0.8 s upward on a really fast machine.

It turned out that the debugging mode was responsible for this
behaviour. Profiling revealed that about 95 % of the time
was spent in the function "posixpath.walk", used by the
"Filesystem Directory View" to determine whether it is still
up to date.
Switching to non-debug mode reduced the duration of simple
request by two orders of magnitude (7 ms rather than 840 ms).


Thus, when you see a slow CMF, consider switching to non-debug mode.


There are probably less expensive ways to let "Filesystem Directory View"
determine whether it needs to reload its data. It probably should
only check the modification time of the folder (to detect
deleted or added objects) and let child objects ensure they are
up to date if and only if they are really accessed...



Dieter