[Grok-dev] Dolmen and its releases

Souheil CHELFOUH trollfot at gmail.com
Fri Oct 23 09:52:32 EDT 2009

I released a new version :

If people are interested to review it, i'll be most happy
Thank you Martin for your tips and feedback.

2009/10/23 Souheil CHELFOUH <trollfot at gmail.com>:
> What you say only worths for the Blobs.
> For a non-blob file, it makes sense to keep a separate file.
> It's easy to provide a non Persistent version of a blob
> It's not for a File, since zope.app.file inherit itself from Persistent.
> There is at least on interest motivating a separate blob object,
> containing a Blob:
> It can be moved out of your object and act as a normal object.
> That being, providing a "BlobValue" is trivial
> providing a FileValue is senseless
> I wonder what the performace impact is, keeping a BlobFile with an
> independant connection as an attribute.
> It can think of several usecases, that would modify the BlobFile
> itself and not the object containing it.
> How do you solve that, in Plone, to handle an object containing a
> named blob file ?
> I didn't see any solution provided for that in plone.namedfile
> 2009/10/23 Martin Aspeli <optilude+lists at gmail.com>:
>> Souheil CHELFOUH wrote:
>>> After discussing this matter with several persons, it appears that the
>>> fact the File has its own _p_jar is not really a problem.
>>> As the file is often a "big" chunk of data, it makes sense to has a
>>> separate object, in the zope point of view, so when you load our
>>> object containing a file, you don't load the file with it.
>>> Performance wise, i'd say it doesn't have a negative impact, it's more
>>> than balance by that situation.
>>> What do you guys think ?
>> I think it depends on your use case:
>>  - if you've got a big file, it should be a blob; in this case, the
>> blob container (which also stores filename etc) probably shouldn't be a
>> separate persistent object, since the blob is one already.
>>  - if you have a small file and you will render its contents often when
>> the object is loaded, avoiding a separate object load may be beneficial
>> Martin
>> --
>> Author of `Professional Plone Development`, a book for developers who
>> want to work with Plone. See http://martinaspeli.net/plone-book
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