Jim Fulton wrote:
On Jan 29, 2007, at 5:46 PM, Philipp von Weitershausen wrote:
After refreshing a product, Zope 2 uses the following stanza in App.RefreshFuncs.autoRefresh() to let the ZODB know that it should invalidate its pickle caches:

        ... refresh products
        from ZODB import Connection

That is really weird code.  It looks very brittle.

That way, persistent objects will use the newly reimported classes instead of continuing to use the old, no longer current classes.

I suppose that was the intent.

For grok I tried to implement the same mechanism and copied that code almost verbatimly, only to find out it doesn't seem to work. Persistent objects will still be instances of the classes that should have been thrown away during the re-import of modules.

Testing product refresh with both Zope 2.9 and 2.10 produces errors for me while Zope 2.8 works, which leads me to the assumption that a cache invalidation bug was introduced after ZODB 3.4. Is anybody else seeing this?

The way that connections were managed changes quite a bit in 3.4.

I'm a bit surprised nobody else has complained about this so far...

Maybe people finally stopped using product-refresh because it doesn't work

What do I have to do to make it work reliably? I'd like to avoid having
to restart all of Zope. (Note that this is grok on Zope3, not
necessarily Zope 2).

Help with tracking this down would be greatly appreciated.

Shane originally wrote this. Maybe he could help out. I'm not interested myself. In fact, I'l be happy to see this code get ripped out. If it stays in it needs a doctest to prevent future regression and to explain how to use it, including what it's semantics and limitations are.

So, are there any alternatives that let me refresh modules w/o server
restarts AND make the ZODB aware of this? Would closing and reopening
the database altogether be an option? I would assume it would leave the
connections that other threads have to the database in a funny state,
but I don't understand a whole lot about ZODB internals so I'm just

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