[Twisted-Python] Using sqlalchemy in twisted.

[Eero Nevalainen]

Peter Cai wrote:
> If you Google "sqlalchemy twisted", you can see my post is on the top:
> 
> http://groups.google.com/group/sqlalchemy/browse_thread/thread/c802749c9d0dd6
> 
> I've been busy for a long time so I didn't considered this question
> anymore.  But occasionally, I got some new ideas today.
> 
> I was suggested to sandbox sqlalchemy into process contains a single thread.
> At that time, I thought it was just the same as using deferToThread
> and makes no scenes to have the overhead of IPC.
> 
> But now I see the benefits.
> 
> A single thread process makes it possible to use a sqlalchemy session
> as a cache.  That would greatly reduce the chances to lookup database.
> This could not be done with deferToThread because it uses thread pool.
>  So there shall be more than one session and the state of cached
> objects will conflict.
> 
> But there are still one problem : how to transfer a sqlalchemy object
> between 2 process?  Some kind of serialization and de-serialization is
> needed.  Without test, it's too early to tell if it works.
> 

Is there a reason why multiprocessing could not be used?

http://docs.python.org/library/multiprocessing.html#exchanging-objects-between-processes

-- 
Eero Nevalainen