[ZODB-Dev] TemporaryStorage and ZEO2

[Jan-Wijbrand Kolman]

Hello,


At the risk of addressing this to the wrong people or asking very 
silly things, I have a question regarding TemporaryStorage and ZEO2.

Infrae develops Silva and does the deploy Silva on a ZEO cluster. 
Since Silva heavily depends on sessioning and since the loadbalancer 
in use does not garantuee an end-user to connect to the same ZEO 
Client node once a session is "started", these sessions need to be 
shared over the nodes.

We used to use (on a ZEO1 setup still) the bsddb3Storage to store the 
sessions in, using ExternalMount to mount this "session storage" on 
the ZC.

Now that we want to migrate to Zope2.6.1, DBTab and ZEO2, I started 
investigating the possibilty to use a TemporaryStorage on the ZEO 
StorageServer (the DBTab documentation suggests this is possible).

So far I got this working, but to do so I had to subclass 
TemporaryStorage and adding three methods to this subclass: 
supportsTransactionalUndo, supportsVersion and supportsUndo (all 
returning 0). ZEO2 seems to assume that these attributes are available 
on the Storage implementation.

Now the question: is there any reason for TemporaryStorage not to 
implement these methods? (other than, maybe, noone got arround doing 
so yet :)

I'm happy to provide more details on my setup, if needed!


TIA
regards,
jw

-- 
Jan-Wijbrand Kolman
jw@infrae.com