[ZODB-Dev] Fixing POSKeyErrors :-)

[Chris Withers]

Jim Fulton wrote:
> 
> There's also a problem that we made cross-database references so easy to 
> make that they are made accidentally. 

There's also no way to say "actually, I want to *move* this object to 
this other storage.

Semantically, that's what my customer was trying to do...

> make them more explicit, at least optionally.  I think where people have 
> gotten into trouble is where they've mounted content trees into other 
> content trees and then moved objects between trees creating 
> cross-database references accidentally. 

Bingo. I should note that while I often make use of mounted storages for 
two reasons:

1. More control over object cache contents
2. Different packing schedules for different sections of the tree
    (ie: imported content is packed to nothing straight away, other stuff
     is never packed if I can help it)

...I rarely create cross-database references.

> In the longer term, multi-database GC is an option. I believe this will 
> be doable.

That would be handy, as would multi-database Undo as you mentioned later 
in the thread.

cheers,

Chris

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