[Twisted-Python] Twisted.Persisted ~ ZODB
python at praxsys.com
Thu Jul 1 19:07:13 EDT 2004
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.
Jp Calderone wrote:
> Eugene Coetzee wrote:
>> 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.
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