ZODB.POSException.ConflictError on attribute assignment
I'm getting a ZODB.POSException.ConflictError in the following code in a Custom Zope Product, and I'm hoping someone can enlighten me on how to fix it. # nd is a folder with a sub-folder "Categories # "NDCategory" is a custom Zope product I wrote that does not have anything called "bogus" defined. categories = nd.Categories.objectValues('NDCategory') for cat in categories: cat.bogus = [] Can anyone explain this to me? Thank you in advance, Brian Rosenthal -------------------- Brian Rosenthal General Partner, RoboCommerce, LLC brian@robocommerce.com http://www.robocommerce.com 800-644-7626
zope-dev@rosenthaltechnologies.com wrote:
I'm getting a ZODB.POSException.ConflictError in the following code in a Custom Zope Product,
Google for "ConflictError Zope" and read, a lot. These are to be expected due to Zope's concurrency model, but if end users are seeing them then your application needs restructuring.
# nd is a folder with a sub-folder "Categories # "NDCategory" is a custom Zope product I wrote that does not have anything called "bogus" defined. categories = nd.Categories.objectValues('NDCategory') for cat in categories: cat.bogus = []
how many categories are there and how often does this code get executed? cheers, Chris -- Simplistix - Content Management, Zope & Python Consulting - http://www.simplistix.co.uk
how many categories are there and how often does this code get executed?
It's only one user and within one request where this is happening. I'm using ZEO. There must be something I fundamentally don't understand about how I assign an attribute to an object in the ZODB. If you have any insight nere, I'd appreciate it. Best, Brian On Fri, 01 Sep 2006 09:40:24 +0100, "Chris Withers" <chris@simplistix.co.uk> said:
zope-dev@rosenthaltechnologies.com wrote:
I'm getting a ZODB.POSException.ConflictError in the following code in a Custom Zope Product,
Google for "ConflictError Zope" and read, a lot. These are to be expected due to Zope's concurrency model, but if end users are seeing them then your application needs restructuring.
# nd is a folder with a sub-folder "Categories # "NDCategory" is a custom Zope product I wrote that does not have anything called "bogus" defined. categories = nd.Categories.objectValues('NDCategory') for cat in categories: cat.bogus = []
how many categories are there and how often does this code get executed?
cheers,
Chris
-- Simplistix - Content Management, Zope & Python Consulting - http://www.simplistix.co.uk
-------------------- Brian Rosenthal General Partner, RoboCommerce, LLC brian@robocommerce.com http://www.robocommerce.com 800-644-7626
On 9/1/06, zope-dev@rosenthaltechnologies.com <zope-dev@rosenthaltechnologies.com> wrote:
I'm getting a ZODB.POSException.ConflictError in the following code in a Custom Zope Product, and I'm hoping someone can enlighten me on how to fix it.
# nd is a folder with a sub-folder "Categories # "NDCategory" is a custom Zope product I wrote that does not have anything called "bogus" defined. categories = nd.Categories.objectValues('NDCategory') for cat in categories: cat.bogus = []
Feels like you might be miss interpreting what a ConflictError is. With some hand waving... ConflictErrors are _not_ a mechanism for prohibiting attribute assignment because that attribute already exists. Instead ConflictErrors are a mechanism to prohibit inadvertent concurrent updates of the same attribute. (Or in older ZODB's, even concurrent reading of an attribute that is being written too.) Check the traceback for your ConflictError to get some details about just what is in conflict. Also might be worth a look in the access logs to see what else might be happening on the server at about the same time. Cheers Michael
Michael Dunstan wrote at 2006-9-2 10:58 +1200:
... ConflictErrors are _not_ a mechanism for prohibiting attribute assignment because that attribute already exists. Instead ConflictErrors are a mechanism to prohibit inadvertent concurrent updates of the same attribute. (Or in older ZODB's, even concurrent reading of an attribute that is being written too.)
A minor correction: not concurrent updates to the same attribute but of the same persistent object. -- Dieter
participants (4)
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