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

Benji York benji at benjiyork.com
Thu Jul 15 02:20:02 EDT 2010


On Wed, Jul 14, 2010 at 6:59 PM, Leonardo Rochael Almeida
<leorochael at gmail.com> wrote:
> On Wed, Jul 14, 2010 at 19:22, Benji York <benji at benjiyork.com> wrote:
>> [...]
>> 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.

Indeed.  My jet lag ate that part of the story.  Thanks.

> 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?

If this were me, I'd use a non-temporary storage and implement an expiry
policy for the results cache.  The bforest package would be a good start
(http://pypi.python.org/pypi/zope.bforest).

In fact, I would expect they already have an expiry policy in place, so
they might be able to just start using a non-temporary storage right
away.
-- 
Benji York


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