[pmwiki-users] Re: Re: Re: Using AllRecentChanges as a shared page between fields

[Patrick R. Michaud]

On Mon, Jul 25, 2005 at 12:10:31AM +0200, Joachim Durchholz wrote:
> >2. Because cleanup processes sometimes come in and destroy the files 
> >in /tmp, which isn't always helpful to PmWiki.
> 
> "not always helpful" would be an understatement, but the cleanup
> processes don't delete files that haven't been touched in days. I'd
> assume that PmWiki doesn't need its temporaries around for such a long
> time - or does it?

They aren't always "temporary"  -- sometimes PmWiki needs a scratch
pad where it can store data across invocations.  For example, the 
.lastmod file is used to help manage browser page caching (and soon 
page formatting), but .lastmod might not be updated for a very long 
time if there aren't any updates.  If the file disappears it won't 
cause things to stop working, but it does mean that PmWiki will 
stop making use of caches, because it has no idea when the last 
modification took place.  (Similar arguments can be held for .mailposts.)

> I'm got a PAM module installed that sets up a separate directory 
> for each process in /tmp. This eliminates race conditions that are 
> otherwise commonplace around the creation of a temporary file. 

Of course, this would also invalidate PmWiki's purpose for having a 
work directory, which is to allow one process to easily communicate 
status information to other later processes. 

Pm