[ZODB-Dev] Data lossage

[Dieter Maurer]

Paul Winkler wrote at 2003-9-3 12:09 -0400:
 > ...
 > The problem: 
 > I've experienced intermittent data loss over the past few weeks.
 > There were two instances, the first involving about 10 different
 > objects. Both times, the pattern was something
 > like:
 > 
 > 1) content administrator changes something
 > 2) a few days pass
 > 3) content administrator goes back to the object and reports
 > that changes from #1 have vanished - object has reverted
 > to an earlier state (or, if it was new, the object has vanished).

As a file storage only looses information during a pack
(and you reported there were no pack operations in the meantime),
this sounds not very likely.

Probably, the object has not been changed in the first place or
someone reverted to an earlier state explicitly.
I once analysed a similar problem. It turned out that a colleague
had deleted a folder and later recreated through an "import".
Unfortunately, the imported object contained somewhat old data...


I patched "fsdump" to allow to specify a start and end
transaction. This way, all transactions in some interval
can be specified.
However, when you site has a moderate number of modifications,
it may be a huge task to look through several days of transaction
logs...
When you know the affected object ids (your changing object
and that of its container), you can search through the "fsdumg"
Output for these OIDs.


Dieter