Re-add support for bulk_create

[dehnert]

Between 1.8.0 and 1.8.6 (#380), reversion used bulk_create when creating versions, which presumably dramatically improved performance when creating a revision with many changed model instances[1]. It sounds like the motivation for removing this was inability to get back object primary keys from bulk_create, but that has since been fixed on some popular databases -- Django 1.10 (released about a year and a half after #380) added some support (only PostgreSQL at the time). SQLite was added in Django 4.0, and MariaDB was added sometime in the middle. It looks like there's a convenient feature test for this (connection.features.can_return_rows_from_bulk_insert), so it would be nice if django-reversion could use bulk_create when feasible.

(I found #380 while trying to figure out why tons of queries were being used despite the changelog claiming reversion uses bulk_create, so if you don't re-add bulk_create support it might be nice to note the change somewhere?)

[1] I haven't benchmarked this specifically, but a script that creates several thousand objects went from 30 minute runtime to ~3 minutes by doing far more query batching, so I suspect this is significant.

[spapas]

Hello friends, this would be really useful to me also. I've got some objects that I create through bulk_insert or update with bulk_update and I am forced to save them one-by-one to have proper revisions.

[etianen]

I'm a bit short on time at the moment, but I'd be happy to take a PR that implemented this.

[stianjensen]

Hello friends, this would be really useful to me also. I've got some objects that I create through bulk_insert or update with bulk_update and I am forced to save them one-by-one to have proper revisions.

So this, specifically, is another problem than what's described in this issue! A workaround for your problem is explained here:
#925

Essentially, if you use bulk_create or bulk_update to update a lot of models in one query, also iterate over the objects and call add_to_revision on them (that does not by itself cause one immediate db query per model). Then, until this issue gets fixed, that will cause n queries upon save to create the n versions, but hopefully in the future, with a fix for this issue, that saving of the n versions will also itself be performed via only one bulk query (plus one extra query to save the Revision model instance).