tangentlabs/django-oscar — comment on commit 63175fb31a9a3d5a274d324b44d2b12969292257
File: oscar/apps/product/abstract_models.py line 49
By AndrewIngram:

It may not need to be 1024, but it's quite probably that it'll need to be greater than 255. Reason being that the slug is generated based on the all the parent nodes, so it could end up being a lot longer than it would be if it was just based on the current node.

We had the same problem with migrations on Landmark, I don't know if we found a good workaround for it. The issue seems limited to MySQL though.