[ZODB-Dev] undo / non-undoable

[Jeremy Hylton]

On Mon, 2004-02-16 at 20:00, Harm_Kirchhoff at mail.digital.co.jp wrote:
> When I lost some data and tried to wheel my ZODB back to the state 
> before, I encountered that any transaction seemed to be undoable.
> 'UndoError: Undo error None: non-undoable transaction', no matter in 
> which order I tried to undo the last 5 transactions.
> 
> >From my research in the internet and mailing lists, I can not explain 
> this error. My understanding is, that if you try to wheel back, 
> transaction by transaction starting from the most recent, there should 
> generally not be a problem, because there can be no more recent 
> transactions which depend on the changes made, since each transaction I 
> undo is the most recent.

Did you pack the database before you tried to undo?  Pack is a
destructive operation that removes non-current data from the database. 
It isn't possible to undo operations before the pack time, because any
non-current data they contained is gone.

If you did pack, then the data is really gone.  You'll need to salvage
what you can from a backup.

Jeremy