Re: Rollback?

Wolfgang Keller <[email protected]> Mon, 18 Sep 2006 13:56:34 +0200
Newsgroups gmane.comp.python.modeling
Message-ID <[email protected]>
>> Is the possibility to rollback changes on the roadmap of Modeling? This is 
>> for the case where several instances of an application using modeling run 
>> in 
>> parallel at different sites, and a transaction needs to be distributed over 
>> more than one instance of the application...
> 
> I'm not sure to understand what you mean by "a transaction needs to be 
> distributed over more than one instance".

Well, a distributed transaction.

Two database servers, two applications, one application on each server, both 
applications use modeling for persistence and are connected to each other 
through RPC.

But I figured out that it will be more efficient to simply link the 
underlying databases with multi-master replication instead of doing it at the 
application level.

So don't bother for my stupid question...

> Explicit database-locking would be called Pessimlistic Locking, where 
> modifying an object implies acquiring a lock on the corresponding database 
> column(s) until changes are saved (or discarded).  This feature is on the 
> TODO list, but development has not started yet.

Any realistic estimate when it will be available?

In a transaction-intensive application, not having pessimistic locking will 
mean getting lots of transaction failures, I guess? And lots of handwork to 
clean up afterwards...

What I am in fact looking for is something that allows transactions at the 
object level to be as ACID as PostgreSQL transactions at the database level.

Am I just dreaming?

TIA,

SIncerely,

Wolfgang Keller

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