Hello,
The bug report contains a more detailed explanation of the patch, but
there are some points I thought might lead to some discussion.
First a quick summary of the issue: mod_session writes out the session
every request even if there aren't any changes to the data. This makes
some sense when the session has a max age and the expiry value needs to
be refreshed. However, there isn't likely to be much benefit in
repeatedly refreshing the expiry by a few milliseconds, possibly
generating database traffic each time. This patch proposes a new
directive to define an interval of time where the expiry doesn't need to
be refreshed if there are no session data changes.
1. We had a hard time coming up with a name for the directive. The patch
goes with SessionExpiryUpdateInterval, being the interval of time that
may pass before updating the expiry value is required. I don't know if
there are any existing directives with a similar function that we should
mimic instead.
2. The patch includes a behavior change independent of the new directive
when using sessions without a max age: if the data hasn't changed, don't
write out the session. Most noticeably, this means new sessions that
never get data are discarded without being saved.
3. I wasn't sure how best to add tests for a new directive since the
test server won't start if the directive is missing. The patch that
includes the test changes look for the 2.5 version to know the new
directive is there, and will require a modification if/when the
directive is back-ported to 2.4 to enable the new tests.
https://bz.apache.org/bugzilla/show_bug.cgi?id=57300
Thanks for your consideration.
--
Paul Spangler
LabVIEW R&D
National Instruments
