How to debug session error

[11175]

My rails (1.1.6) wep application has been working fine for months, with
15 000 user per day. never had any problem with session.

Then I added a new feature to my app, and, after 4 to 6 hours, sessions
start to be lost.
I mean, i set a session["a"] = stuff, at the next call, session["a"]
will be nil !!!
So my user can not login...because of the session["user_id"]

If i restart my application, it works fine for an extra 4 to 6 hour.

If i rollback my application to before the new feature, it works fine.

here is my new feature:

begin
        timeout(15) do
    puts system( EXECUTE AN OPENOFFICE MACRO )
  end
rescue Timeout::Error => err
  log
rescue Exception => err
  log
end

So the new feature is to upload user file, and handle then with an
openoffice macro with a system command...

Sometime, the command fail...

Could it be possible that this command have some impact on the rails
session managment system ?

My session are stored in a Mysql DB.

Please help, any clue are welcome

[Frederick_Cheung]

My rails (1.1.6) wep application has been working fine for months,
with
15 000 user per day. never had any problem with session.

Then I added a new feature to my app, and, after 4 to 6 hours,
sessions
start to be lost.
I mean, i set a session["a"] = stuff, at the next call, session["a"]
will be nil !!!
So my user can not login...because of the session["user_id"]

If i restart my application, it works fine for an extra 4 to 6 hour.

If i rollback my application to before the new feature, it works fine.

here is my new feature:

begin
       timeout(15) do
   puts system( EXECUTE AN OPENOFFICE MACRO )
end
rescue Timeout::Error => err
log
rescue Exception => err
log
end

You may be running into the problem I wrote about here: http://www.texperts.com/2007/05/01/race-conditions-in-rails-sessions-and-how-to-fix-them/

Short version: because you've got such a long running action, it is
very likely that you'll get concurrent requests from the same user and
the different updates to the session overwrite each other.

Fred