[Zope] duplicate or 'echoing' REQUEST?

[Jim Abramson]

Thanks.  Well it's not actually good news.  I use Oracle9i!

If these are ZODB Conflict Errors, should I expect to see them in the
event log?  (My ORA-00001 errors are there but I see no conflict
errors.)

Lets say I moved all my db logic into external modules, hiding any
references to database connections or result objects completely from the
ZODB and any ZODB-based assets like DTML, PythonScript etc...would you
expect this to solve the problem?

Jim


-----Original Message-----
From: Chris McDonough [mailto:chrism at plope.com] 
Sent: Tuesday, August 31, 2004 4:57 PM
To: Jim Abramson
Cc: zope at zope.org
Subject: Re: [Zope] duplicate or 'echoing' REQUEST?

This is almost certainly due to a ZODB phenomenon known as a conflict
error.  You can probably google around for "zope conflict error" or
"zodb conflict error" to get a sense of what these are, or read the
"Sessions" chapter of the Zope Book for a short overview.

The easiest way to prevent needing to think about it is to use an RDBMS
with transaction support (I suspect you're using MySQL tables without
InnoDB, right?).  If you can't do that, and you can't live with the
result of the conflict errors, you'll need to really dig into Zope guts
to prevent duplicate insertions; this is not recommended.

On Tue, 2004-08-31 at 16:35, Jim Abramson wrote:
> Hi there,
> 
> Running 2.6.0 we have a curious intermittent syndrome involving what 
> we _suspect_ to be multiple identical incoming POST requests.
> 
> To be honest, this could be any number of things happening...however
the 
> most obvious one (user clicking submit twice on the same form) has 
> been eliminated, after quite a bit of testing on various browsers 
> (clicking submit as many times as possible before the current html 
> page/form "leaves" does not reproduce the issue).
> 
> The problem ends up manifesting with unique-key violations from the 
> external rdbms, where it's trying to update or insert some row twice 
> in succession.  Or, more annoyingly, quiet double-insertion of some 
> submitted data.
> 
> Before we turn zope upside down and shake the hell out of it, has 
> anyone out there experienced a similar situation, or know of a 
> programming or configuration error that might lead one to expect this 
> behavior?
> 
> Thanks for any advice,
> 
> Jim
> 
> 
> 
> 
> ______________________________________________________________________
> _______________________________________________
> Zope maillist  -  Zope at zope.org
> http://mail.zope.org/mailman/listinfo/zope
> **   No cross posts or HTML encoding!  **
> (Related lists -
>  http://mail.zope.org/mailman/listinfo/zope-announce
>  http://mail.zope.org/mailman/listinfo/zope-dev )