[Twisted-Python] Twisted.Persisted ~ ZODB

[Kevin]

you might also look at http://modeling.sourceforge.net/

it is definitely different than other persistance layers in python- but 
if you have a background similar to mine, it will feel more comfortable 
to some of these other systems.

good luck,
kevin

Jp Calderone wrote:

> Eugene Coetzee wrote:
>
>> Hi,
>>
>> Being new to both Twisted and ZODB and not finding too much info on 
>> Twisted.Persisted by googling I have decided to post this question.
>>
>> I have also noticed a few projects running Twisted "on top of"  ZODB 
>> as it were.
>>
>> I get the impression that Twisted.Persisted is more of an utility 
>> add-on  to Twisted whereas ZODB is a full fledged object database.
>
>
>   That is true.  Nothing in twisted.persisted is usable by itself as a 
> persistence mechanism for a non-trivial application.
>
>   AOT and Marmalade are graph serialization formats.  Neither supports 
> new-style objects very well, IIRC.  Even if they do, neither is 
> particularly quick, nor provides anything beyond simple storage of a 
> complete object graph, hardly the only requirement for a database.
>
>   dirdbm is a cute toy, but not again really useful as a non-trivial 
> data store.  It's slow and fragile, and doesn't provide any 
> functionality beyond what the bsddb module in Python 2.3 provides.
>
>   sob is a handy front-end to AOT, Marmalade, pickle, and tac files.
>
>   crefutil is helper code for aot and jelly and perhaps some other 
> serialization modules.
>
>   The styles module has all the cool code.  It lets you pickle 
> otherwise unpickleable types and provides the Versioned class, which 
> lets you deal with mixing old data with new code.
>
>>
>> Still - I  would very much like to  use Twisted.Persisted for 
>> trancient data/metadata in a new project I'm tackling cause it is 
>> always good to minimize dependencies and I know I can use postgreSQL 
>> with Twisted for heavy duty stuff - which I still believe a better 
>> option than OODB.
>
>
>   Unless you have very little data, and you don't care _terribly_ if 
> you lose it, twisted.persisted probably isn't going to do it for you.
>
>>
>> How does Twisted.Persisted  compare to ZODB - if such a comparison 
>> can be made? Any other OODB's to be considered for use with Twisted?
>
>
>   You might look at Atop.  It's somewhat lighter weight than ZODB. 
> http://www.divmod.org/ has some docs, but it needs more.  It also 
> isn't distributed separately from Quotient yet (but is easily 
> separable once you download it).
>
>>
>> I would also very much appreciate some links to on-line docs/examples 
>> regarding Twisted.Persisted if they exist.
>> kind regards,
>>
>
>   I wish I could point you at something, but I hope the above has been 
> an adequate substitute.
>
>   Jp
>
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