[ZODB-Dev] undo / non-undoable

[Harm_Kirchhoff at mail.digital.co.jp]

 No, positively no. I never packed it. In fact, if I go into the data.fs 
with a disk editor, I can see that the data for 2003 is still present.
I already recovered the data by brutally copying a backup of the data.fs, 
but next time, I would like to do it more elegantly and I would like to 
understand the problem, because the undo feature is a good thing, which I 
would like to be able to use.

The problem is the same as in the sample code, that I attached in my 
previous message. There, too, I never pack (as you can see). Nevertheless, 
the transaction seem to become non-undoable and I do not understand why. 
It must have something to do with the way I save data in the example.

Harm

----- 転送者:  Harm Kirchhoff/JP/Schneider 転送日: 2004/02/17 12:43 -----


Jeremy Hylton <jeremy at zope.com>
2004/02/17 12:04
jeremy へ返信してください

 
        宛先:   Harm_Kirchhoff at mail.digital.co.jp
        cc:     zodb-dev at zope.org
        件名:   Re: [ZODB-Dev] undo / non-undoable


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