One of the things that was most challenging and still rough around the edges are backfills. Doing a BC breaking schema change in a chain of materialized view an

One of the things that was most challenging and still rough around the edges are backfills. Doing a BC breaking schema change in a chain of materialized view and repopulating can take a week or more for a big dataset. So having stable tooling to help guide that change was super helpful for some of our past migrations.