[openstack-dev] A proposal for RPC-friendly objects

Dan Smith dms at danplanet.com
Tue May 7 00:52:51 UTC 2013

Hi Matthew,

> *Possible Cons:*
>    - Possible performance issues, for example, some code that updates
> a bunch of objects in a list, may not realize that each save() is
> going across 2 amqp servers to reach the DB. This could be worked
> around by adding a 'bulk update wrapper object' and using that (and
> having it do the actual saving at the end). I'm in favor of something
> like:
> with Transaction() as t do:
>   for obj_id in ids:
>      obj = Obj.get_by_id(obj_id, t)
>      obj.foo = 'x'
>      obj.save()

Yep, this could be cool. I don't think we have any situations where we
bulk-modify objects and write them back with a single call, at least
none that come to mind. However, the thought I had for optimizing the
get-all case could probably be used to optimize the write case,
even above what we have today:

If we have an object called Instance, we could also have an Instances
object which is a collection of Instance objects. It would provide the
get-all and get-all-by-foo methods. It could also provide a set-all
method that would effectively call .save() on any of the items it
contains that are dirty.



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