[Zope-dev] Re: [ZODB-Dev] Getting rid of ZODB versions (was Re: [ZWeb] Are Versions evil?)

[Christian Robottom Reis]

On Fri, Jul 16, 2004 at 08:39:52PM +0200, Dieter Maurer wrote:
> > In either case, if you have
> >resource contention, you are probably out of luck.
> 
> Luck is not a binary concept ;-)
> 
> Our current most essential use case for "Version"s is reindexing
> large catalogs. Reindexing can take hours. It is bad when
> the reindexing fails due to a write conflict. It is much
> more acceptable when an intervening occational catalog update
> fails with a "VersionLockError".

I am so happy Dieter happens to come up with a perfect Zope-compatible
use-case to justify this.

This is *so* true for any application that isn't a Web application. When
you have long-running transactions with lots of objects being modified,
it is certainly better to deny access to someone else up-front ("This
resource is unavailable. Go get some coffee.") than to let this person
start and then have them either conflict at the end or have *you*
conflict at the end. Yes, it's not something to be used as a rule, but
for certain operations it is just *so* essential.

Take care,
--
Christian Robottom Reis | http://async.com.br/~kiko/ | [+55 16] 3361 2331