The best schema change is the one your API consumers never hear about. We designed Basalt so most changes are exactly that.
Additive changes are instant
Adding a column or a new event field is a metadata change. New writes carry the field, old rows return null, and every view keeps serving without a deploy.
Breaking changes run side by side
- Basalt builds v2 of the view in the background from the log.
- v1 keeps serving until v2 has caught up to the present.
- You switch traffic with one click, and can switch back.
In the console the whole flow is one screen with a progress bar and a diff of the two schemas. Teams ran 4,100 breaking migrations last quarter with no downtime.
Sigrún leads the query engine team in Reykjavík. Before Basalt she worked on storage at a Nordic payments company, where she learned to distrust any latency number without a percentile next to it.
