[Zope-DB] Zope database connectivity

[Maciej Wisniowski]

> My error was about self.db attribute in
> '_v_database_connection' not about '_v_database_connection'
> attribute itself. During abort() of this resource manager
> self.db was None so self.db.rollback() failed. I'll check
> this again...
I've messed up things. Error that I've found is in
StoredProcedures in DCOracle2 -> SP.py and
this issue seems to be specific to DCOracle2 SP class.

SP class is ResourceManager that uses self._v_db
attribute that is in fact another ResourceManger.

When stored procedure in database raises an exception
self._v_db attribute of SP class instance disappears
(if it was created during same request). As a result
"AttributeError: _v_db" is raised when ResourceManager (SP)
is being aborted because it tries to call self._v_db.db.rollback().

I'm not sure why DCOracle2 treats SP as another
ResourceManager while it still uses same db connection as
the other ZSQLs etc. As a result if we have a lot of SP calls
during one request there is a lot of commits (rollbacks) to the same
db connection. Maybe it's something about caching procedure
objects in volatile attributes.

-- 
Maciej Wisniowski