On Sat, Oct 4, 2008 at 6:00 PM, Josh Heitzman <[EMAIL PROTECTED]> wrote:

> As far as transactions go, the global coordination is already there at
> the entity group level (if it wasn't, then there wouldn't be any
> transactions at all).  Sure it will be more costly at the entity level
> then at the group level, but it will still be less costly then
> layering the equivalent on top of the data store API in the python
> application code.  Allowing transactions spanning entity groups,
> doesn't mean that entity groups and non-spanning transactions need be
> eliminated.  Leave it the application developer to choose the
> appropriate transaction type as needed.

You're right, application-wide transactions don't have to subsume
entity-group transactions; you could, after all, put every entity in
your application in a single entity group. They are, however, still
inherently unscalable. Entity groups mean that global coordination is
*not* required, only that there is a "home" for each entity group. As
long as the entity groups are small, this responsibility can be split
across machines quite easily.


Dave.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups 
"Google App Engine" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at 
http://groups.google.com/group/google-appengine?hl=en
-~----------~----~----~----~------~----~------~--~---

Reply via email to