[Zope] Data Insert Problems

[Dieter Maurer]

Jay Zeemer wrote at 2005-3-21 15:46 -0500:
>I am currently running into an issue with an application I am working.  I
>have a form, currently 5 fields but will soon grow to be much larger, and
>when I run 50 conncurrent users against it from Open STA.  Of the 50
>attempts I am seeing about 60% of them actually completed in the SQL
>database, I am seeing an error of:
>
>ZODB conflict error at
>/VirtualHostBase/http/server.domain.com:80/VirtualHostRoot/dir1//dir2/submit
>/processForm (27 conflicts since startup at 2005-03-21T13:33:44)

This means that several requests tried to concurrently
write to the same object.
>
>Most of what I have found in digging is that data write intensive
>applications may have this issue, but I was wondering if anyone could
>recommend away around this?  Could any one tell me what is happening that is
>causing this, the processForm object writes out to a SQL database, not to
>the ZODB??  

A relational database can have the same issues as the ZODB
(transaction aborts due to concurrent conflicting writes).
A good database adapter will map this case to a
"ConflictError".

However, it is more likely that you write to the ZODB indeed -- probably
unexpected. There is a patch around (from me) that
makes "ConfictError" reports more informative. Search
for it an apply it. The additional information allows to
identify the object being wriiten to concurrently.

-- 
Dieter