[Zope-dev] Session Errors

[Dieter Maurer]

Hi Chris,

Chris McDonough wrote at 2003-3-15 12:40 -0500:
 > ...
 > - The first is that turning off read conflicts allows for the potential
 >   for the session data bucket and the session data index to become out
 >   of sync.  I admit that I knew this already, but haven't figured out
 >   a way around it yet without having massive numbers of conflicts.
 >   That said, it may be that we can't avoid them and I may turn this
 >   behavior off in the next revision.  Another alternative is to
 >   use a nonpersistent index, but that has other challenges ( it
 >   could also prevent the shared use of session data between ZEO
 >   clients).

You know that we use a Transience implementation with minimal
(and not very essential) administrative data which
is immune to inconsistencies and can be used across several
ZEO clients (although we do not use that).

We have good experience with this implementation.

 > - The second is an unidentified (yet) bug in TemporaryStorage.  Most of 
 >   the code for TemporaryStorage came right out of the Berkeley
 >   "Packless" storage.  I should probably try to replicate this under
 >   load (this should not be difficult).To verify the assertion that
 >   there really is a bug in TemporaryStorage without much trouble,
 >   you could temporarily put your transient object container
 >   (session_data) in the main database and point the session data
 >   manager at it and run for a while under this config.  This is
 >   not recommended for production as it will cause main database
 >   bloat, however.

The problem might also be the "MountPoint" -- with the
connection to the TemporaryStorage not correctly synchronized
with the transaction.


Dieter