Yeah so that would totally be a useful thing to have, but there's no urgency. If you're going to implement this by running a pillow it seems like you might as well just not filter it and add the doc_type in there (also indexed). Querying it for just `CommCareCase`s will still be easy.

Not sure we've ever put that many rows in a single table before on our infrastructure, but this seems like an innocuous enough way to test that. Postgres can obviously handle that amount of data, so if anything happens it'd just be indicative of a bed setup on our part that we should fix ASAP if we want to start moving things over