[ovs-discuss] RFC: incremental computation for OVN with DDlog

[Justin Pettit]

> On Nov 7, 2018, at 8:10 AM, Ben Pfaff <blp at ovn.org> wrote:
> 
>> For those of us doing work right now to add new features to OVN, how should
>> we approach the conversion to DDlog? As an example, I have some multicast
>> work in progress that will add some new northbound data. It also introduces
>> ovn-northd changes to generate logical flows and southbound data.
>> 
>> My assumption is that I should focus 100% on the C implementation for now.
>> When should I consider adding the analogous DDlog changes?
> 
> The DDlog implementation has a lot of catching up to do.  I think that
> other OVN efforts should focus on the C implementation.  Applying recent
> changes to DDlog should not add much to the DDlog work.

To add to this a bit, I'd recommend making sure that you make sure to include unit tests for any new C functionality that's added.  I think the way we're going to do this is allow the DDlog to run in parallel and report any diffs between its output and the C version.  The unit tests will make sure that it gets caught immediately.

--Justin