[Zope-dev] ZEO TempStorage: Odd behavior on ZEO restart

[Leonardo Rochael Almeida]

On Wed, Jul 14, 2010 at 19:22, Benji York <benji at benjiyork.com> wrote:
> [...]
>
> Let me make sure I understand your setup: you have a TemporaryStorage
> running on a central server that is exposed via ZEO to clients.  Right?
>
> So, when the ZEO server restarts the temp storage is reset (it's
> contents don't survive a restart by design), but the clients don't know
> all the objects they "know" about in the temp storage just disappeared.
> Therefore when they go to load one (because it wasn't in their object or
> ZEO caches), the load fails.
>
> Not surprising really.

What could be surprising is that, since the objects are not in the
object cache or the ZEO cache, how can the clients 'know' about them
to request them?

And the answer is probably that there are other objects which ARE in
the object cache, or the ZEO cache and that hold references (ghost
objects in the case of the object-cache) to the objects in the
zeo-distributed temporary storage.

So, perhaps, Sebastian can avoid a Zope restart if he finds a way to
flush all caches. Flushing the object caches is easy, it's in the
Control_Panel. Flushing the ZEO cache is something else. Perhaps he
can run with a 0-sized ZEO cache for the TempStorages?

Cheers,

Leo