django-reversion: Version.object_id lookups too slow

In cases where the pk field of a given model is not an int, the object_id_int is not being used. If a lot of rows exists for this model, it makes the lookups very very slow.

These look ups can be made considerably faster by adding a db_index=True attribute to the text field.

It seems South does allow creating a schemamigration for this and it runs with sqlite and postgresql. Also, Django adds a type specific index (if db supports it).

Is there any reason why this can’t be added?