[ZODB-Dev] Re: Local transactions and mount points

[Jeremy Hylton]

On Mon, 2004-02-23 at 14:40, Dieter Maurer wrote:
> A transaction can (in principle) work as a commit monitor
> for a set of commit clients. Such clients are connection
> to several ZODB storages, relational database connections,
> transactional mail services, ....
> The transaction coordinates the various connections in a two phase
> commit during commit.

Coordination is an important part of the transaction API.  It allows
coordinated activities without requiring explicit connections between
the resources involved in the activity.

> For this to work, all connections must have the *same* transaction.
> This is not the case in the "setLocalTransaction" mode.
> You can use this mode only when you have a single (ZODB) connection:
> no support for multiple ZODB connections, no support for connections
> to relational databases or other transactional subsystems.

If you have multiple ZODB connections, you could call
setLocalTransaction() on each of them and pass the same transaction.  In
this case, you're opting for explicit coordination instead of the
implicit coordination you get by default.

Jeremy