[ZODB-Dev] Checking transaction status?

[JohnD.Heintz]

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Not that this is totally on topic, but I've implemented this module to he=
lp=20
us localize Transactions to threads.  (Also add commit callbacks and my o=
wn=20
version of TM.py if you're interested.)

I've slapped a ZPL licence header on it so have fun.

John

On Tuesday 10 July 2001 15:59, Jim Fulton wrote:
> ender wrote:
> > On Tuesday 10 July 2001 12:30, Greg Ward wrote:
> > >>On 10 July 2001, Christian Robottom Reis said:
> > >>> I think (know?) this can be done with threads, but my app is real=
ly
> > >>> single-threaded right now, and I don't want to have to think abou=
t
> > >>> that right now.
> > >>
> > >>My understanding is that you can do that with multiple Connections.
> > >>I've never tried it, though, so I don't know how it works and I can=
't
> > >>vouch for it.
> >
> > My understanding is that won't work. you could get separate object sp=
aces
> > with multiple connections but of limited utility since they wouldn't =
have
> > transaction isolation. the transaction semantics assign transactions
> > based on thread not connection which get its accessor installed as a
> > builtin. so all objects get registered in the same transaction and a
> > single commit would commit all of them (albeit to different connectio=
ns),
> > but still not the semantics of what christian wants.
>
> This is exactly right.  There are a couple of issues here:
>
>   - The transaction implementation needs to be replaceable,
>     so that you can implement different transaction management
>     policies. I'd like to see:
>
>     o Transactions moved into a separate package (from ZODB)
>
>     o Some attention given to making transactions more controllable.
>
>   - There has to be a way for objects find the transaction manager
>     globally. This seems to mean that there can only be one
>     transaction per thread. Maybe there should be a version of
>     get_transaction that lets you pass an argument (e.g. a connection)
>     that that could contain data for deciding what transaction to retur=
n.
>     Hm. This deserves some more thought.
>
> Jim
>
> --
> Jim Fulton           mailto:jim@digicool.com   Python Powered!
> Technical Director   (888) 344-4332            http://www.python.org
> Digital Creations    http://www.digicool.com   http://www.zope.org
>
> _______________________________________________
> For more information about ZODB, see the ZODB Wiki:
> http://www.zope.org/Wikis/ZODB/
>
> ZODB-Dev mailing list  -  ZODB-Dev@zope.org
> http://lists.zope.org/mailman/listinfo/zodb-dev

--=20
=2E . . . . . . . . . . . . . . . . . . . . . . .

John D. Heintz | Senior Engineer

1016 La Posada Dr. | Suite 240 | Austin TX 78752
T 512.633.1198 | jheintz@isogen.com

w w w . d a t a c h a n n e l . c o m

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