Re: [Zope] Re: FSSession buglette

[Pavlos Christoforou]

On Fri, 7 Jul 2000, Paul Gresham wrote:

 Hi, Yep, I'm definitely running 0-4-0, I think the fact that I did
 something naughty caused the rename (and therefore the commit) to fail,
 when it expected to work. An exception in the commit then caused Zope to
 stop all commits. What is worrying is that someone much more naughty
 than I am, may just do something similar on our live system (Once this
 goes live)

Paul

When I was testing FSSession-0-4-0 before release I created all sorts of
weird situations and at least I got the impression that even under those
situations FSSession would behave ok. I suppose I could make it foolproof
by trying to serialize the contents everytime someone makes changes. This
would guarantee that no exception will be raised during commit, but as I
understand it it should be ok if an exception is raised during the first
phase of commit (ie during tpc_begin). Zope should remain in a consistent
state and the transaction machinery should clean up things ok, if
something bad happens during the first phase of commit. It is only if an
exception is raised in the second phase of commit that Zope refuses to
carry on more transactions. In any case please send me your setup that
creates such a problem with FSSession0.4.0 so I can look into it.

If you want to restrict the kind of objects that your users will store in
FSSession you could swap _dump and -load for the equivalent marshal ones.


Pavlos


___
Zope maillist  -  [EMAIL PROTECTED]
http://lists.zope.org/mailman/listinfo/zope
**   No cross posts or HTML encoding!  **
(Related lists - 
 http://lists.zope.org/mailman/listinfo/zope-announce
 http://lists.zope.org/mailman/listinfo/zope-dev )

[Zope] Re: FSSession buglette

[Paul Gresham]

Pavlos Christoforou wrote:
 
 Paul
 
 Are you running FSSession0.4.0? If not please upgrade. The problems you
 mention below have been corrected. Nevertheless the first problem you
 descripe is not really related to FSSession. What happens is that certain
 Zope objects that can be pickled should not be stored in FSSession.
 Initially FSSession used marshal to serialize python objects, which is
 faster and does not allow storing of instances etc. I moved to pickle at
 the users request but one should be careful what he/she stores in
 FSSession.
 
 FSsession-0.4.0 should not raise an exception in tpc_finish. If I
 understand Zope's two phase commit mechanism, it is ok to raise an
 exception in tpc_begin (which corresponds to the 'polling' stage i
 believe) but not in tpc_finish. So now potential problems like full
 filesystem, unpicklable instances etc should be caught in tpc_begin.
 
 Pavlos
Pavlos Christoforou wrote:
 
 Paul
 
 Are you running FSSession0.4.0? If not please upgrade. The problems you
 mention below have been corrected. Nevertheless the first problem you
 descripe is not really related to FSSession. What happens is that certain
 Zope objects that can be pickled should not be stored in FSSession.
 Initially FSSession used marshal to serialize python objects, which is
 faster and does not allow storing of instances etc. I moved to pickle at
 the users request but one should be careful what he/she stores in
 FSSession.
 
 FSsession-0.4.0 should not raise an exception in tpc_finish. If I
 understand Zope's two phase commit mechanism, it is ok to raise an
 exception in tpc_begin (which corresponds to the 'polling' stage i
 believe) but not in tpc_finish. So now potential problems like full
 filesystem, unpicklable instances etc should be caught in tpc_begin.
 
 Pavlos

Hi, Yep, I'm definitely running 0-4-0, I think the fact that I did
something naughty caused the rename (and therefore the commit) to fail,
when it expected to work. An exception in the commit then caused Zope to
stop all commits. What is worrying is that someone much more naughty
than I am, may just do something similar on our live system (Once this
goes live)

Regards
Paul

___
Zope maillist  -  [EMAIL PROTECTED]
http://lists.zope.org/mailman/listinfo/zope
**   No cross posts or HTML encoding!  **
(Related lists - 
 http://lists.zope.org/mailman/listinfo/zope-announce
 http://lists.zope.org/mailman/listinfo/zope-dev )