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

[Ross Patterson]

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.

Ross