[Zope-CMF] CMF write performance as poor as Plone?

[Tres Seaver]

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Ross Patterson wrote:
> Tres Seaver <tseaver at palladion.com> writes:
> 
>> Ross Patterson wrote:
>>> Tres Seaver <tseaver at palladion.com> writes:
>>>
>>>> Andreas Jung wrote:
>>>>> On 23.11.2008 11:57 Uhr, Charlie Clark wrote:
>>>>>> Am 23.11.2008 um 09:24 schrieb Andreas Jung:
>>>>>>
>>>>>>> This issue is independent of the client-side. ab2 and cmf/plone were
>>>>>>> running on the same (fast) machine.
>>>>>> Is this really content that is suited for the ZODB?
>>>>> I am talking of the standard content-types that are available in CMF and 
>>>>> Plone like Document, News etc.
>>>> Are you trying to proceess feed content, one document per request?  You
>>>> should be batching up that content, to get better amortization of the
>>>> indexing overhead.
>>>>
>>>> You should also be checking for conflict errors:  they would result in a
>>>> *large* performance hit.
>>> Quick question.  How much of the write concurrency problem comes from
>>> the fact that the ZPublisher retries the entire *request* on
>>> WriteConflict instead of just trying to committing the transaction
>>> again?
>> It can't retry the commit:  the point is that the conflict can't be
>> resolved using the values read from the database at the start of the
>> transaction.  We have to redo the whole request, re-reading any objects
>> in the context of a new transaction;  otherwise, we would be back to
>> "last write wins", which is a lose.
> 
> Not really what I meant, sorry for being unclear.  I meant how much of
> the write performance problem comes from the overhead of redoing the
> whole request, rendering templates and such?  I'm just wondering if
> anyone has quantified that.

I doubt anyone has done so:  the results would likely be highly
dependent on the specific application.

Back in the day, the render-time penalty was one of the reasons I
disliked self-posting forms (for updates):  I preferred the
"update-and-redirect" model, both to avoid rendering during / after the
update, and also to avoid screwing up the browser cache with POST requests.


Tres.
- --
===================================================================
Tres Seaver          +1 540-429-0999          tseaver at palladion.com
Palladion Software   "Excellence by Design"    http://palladion.com
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