[Zope-dev] [Bug] Zope's transaction behaviour flawed

[Dieter Maurer]

Toby Dickenson wrote at 2003-2-3 17:04 +0000:
 > On Sunday 02 February 2003 3:40 pm, Dieter Maurer wrote:
 > > Zope's current transaction behaviour is essentially:
 > >
 > > 1   ## request starts
 > > 2   transaction.begin()
 > > 3   try:
 > > 4        object= REQUEST.traverse(...)
 > > 5        mapply(object,...)
 > > 6        transaction.commit()
 > > 7   except:
 > > 8        transaction.abort()
 > > 9        handle_error()
 > > 10  ## request ends
 > >
 > >
 > > This is flawed as error handling is done outside of a transaction.
 > >
 > >    Potential changes during the error handling spill over
 > >    uncontrolled into another request and are there
 > >    either committed or aborted as part of this request.
 > ...
 > 
 > and I 
 > think 
 > there is a flaw in this explanation. Surely any changes that leak out fro
 > m 
 > one request will will be be aborted before they can do any damage, during
 >  the 
 > call to transaction.begin() on line 2.
 > 
 > The doc string from transaction.begin is:
 > 
 >         '''Begin a new transaction.
 > 
 >         This aborts any transaction in progres.
 >         '''
 > 
 > (I should have a chance to experiment with this tomorrow)
Then, we must find another explanation for Andrews observation:

  He observed heavily inconsistent (Zope) session data
  when he accessed the session during error handling.
  The problem went away when he did not do that.

@Andrew:
  Can you check your log files whether
  the events would be consistent with rollbacks at the start
  of the next request.


Dieter