[ZODB-Dev] POSKeyError on startup

[Eoin Curran]

In message <200310030901.09319.tdickenson at geminidataloggers.com>, Toby Dickenson writes:
>On Thursday 02 October 2003 21:54, Paul Boots wrote:
>> At 11:10 +0100 2-10-03, Eoin Curran wrote:
>
>> >POSKeyError: 0000000000000006
>
>oids are allocated sequentially, so your storage has lost the seventh object 
>ever created! Thats quite distinctive. 
>
>Have you run fsrefs to confirm that this is the only missing object? Or is 
>this just the first one to get noticed out of a catastophic loss?

This seems to be the only one. I noticed these errors while i was adding
a new user to the acl_users, but never got any errors apart from key #6.

i don't have a script called fsrefs in my zope distribution. Is it 
available elsewhere?

>
>On a storage created today with zope 2.6.2, oid 6 is a TemporaryFolder 
>instance. Is that a clue to anyone? its not to me.
>
>This sort of damage can be fixed, but it needs surgery. You will need to 
>confirm the type of the object that has been lost, then create a substitute 
>object somewhere else in Zope. Next open the storage outside of Zope, use the 
>storage API to load the pickle of the subsitute object, and store it as oid 
>6.

I'll look into doing this, but with the amount of data that there was,
it may not be worth doing. Is there an easy way to output the contents of
the file in a way that i might pull the important bits out by hand?

>
>> Oops - I'd say start again (with a backup plan).
>> When you can't get to the object causing the error you're basicaly screwed.
>>
>> Does anyone no what sort of events trigger this error?
>> I've had it and never got around the cause. It's a nasty and scary error
>> that made me drop a level in trusting Zope.
>
>If you need for your storage to absolutely never lose objects, then you may 
>want to look at DirectoryStorage. I created it after getting the "you're 
>basicaly screwed" feeling for the second time.
>
>http://dirstorage.sourceforge.net/

great. i'll check that out also.

thanks,

    eoin.