Track · 2:30 · Liner note
Slice It Into Days
Partitioning a table by day splits its data into one segment per date, so queries filtered by date read only the days they need and old days can be dropped cheaply.
Daily partitions make time behave. Slice It Into Days splits a table into one segment per date, so a query for last Tuesday reads last Tuesday, and expiring old data means dropping a partition instead of deleting rows. Reloading a bad day means replacing just that day.
Day is the right grain for most event data and the wrong one for small tables, where it only creates clutter. Keep the partition key in your filters, watch the partition count and be explicit about time zones, since whose midnight counts decides which day a row lands in.