[Mailman-Developers] Re: [Mailman-Users] Big problems with stale lockfiles on large list...

[Nigel Metheringham]

Someone wrote (I got completely lost with the attributions in this and 
can't find the original):-
> I ran into a strange little problem today -- I'm using time() to
> generate a filename for a temporary directory. Works great; until
> you start running multiple processes on a 2 CPU machine. I started
> having two processes get the same time() value (which is
> impossible on a single CPU system) and fight over the same
> directory. I'm now doing a random() based sleep to get away from
> this.

claw at kanga.nu said:
> Bad bad bad bad.  You've just decreased the incidence of collisions,
> not their fact or possibility.  The standard *nix approach is to use
> the process ID which is guaranteed unique.  If you're not running an
> *ix, just have one process use numerically even tempfile names, and
> the other odd. 

Actually you would be better advised to go the Maildir filename 
approach - the filename is made up of the time(), the pid and a machine 
specifier of some form.  That  won't have clashes unless you can wind 
through your pids in under a second (although the current proposals for 
random pids worries me somewhat).

	Nigel.
-- 
[ Nigel Metheringham           Nigel.Metheringham at InTechnology.co.uk ]
[ Phone: +44 1423 850000                         Fax +44 1423 858866 ]
[ - Comments in this message are my own and not ITO opinion/policy - ]