[Mailman-developers] More mailman locking issues

[John Viega]

Well, if one of the lists was left unlocked, there was probably a
bug...  Anyway, WRT. locking, I think that several things need to
happen minimum:

1) Locks should insert a time stamp.  After x seconds (30?) you can
lose the lock.  Anything such as the archiving software should use
that time to copy the archive over to a tmp file and nulling out the
old file so that other procs can overwrite (Not that hard).

2) A version of Load() should be written that doesn't call Lock()
(call it LoadUnlocked() I guess).  Change things that don't care to
use it (Even easier).

3) Make sure Lock() uses portable calls (might require a bit of research).

I can look into this stuff next week, but if anyone wants to do it
sooner, let us know and feel free...

John

On Tue, May 05, 1998 at 03:28:28PM -0400, Ken Manheimer wrote:
> Another issue with mailman locking - i think it's coarse grained, and
> needs to be refined.  For example, this morning someone noticed that
> the umbrella listinfo page on python.org was hanging, because, it
> turns out, one of the lists was left in a locked state.  (Not sure how
> that happened - it usually doesn't.)  Well, the umbrella listinfo (and
> admin) pages open the lists only for the sake of determining which are
> public ones - no writing is actually required, so a lock isn't really
> required.
> 
> It might be sufficient to offer a way to open a list "read-only", such
> that no locking is done.  I think it would be better, however, to
> refine the locking system such that lists are not locked until they
> enter an operation that changes the list data in a way that will
> eventually need to be written.  This would probably take a more effort
> than a "read-only" kluge, but may not be too bad.
> 
> I guess this is one for the todo list.  (Wish i had gobs of time to
> continue to hack on a these sorts of things - they're not very big or
> hard, but there is a bunch of them, and they need to be done right.)
> 
> Ken
> 
> ------------------------------------------------------
> Mailman-developers maillist  -  Mailman-developers@python.org
> http://www.python.org/mailman/listinfo/mailman-developers