Improvements to freshness monitors

We’ve improved our automated freshness monitor to better handle weekly patterns. We've sometimes heard customers refer to these as “bimodal” thresholds… meaning one threshold during weekdays, and a different threshold during weekends. These are valuable when the table updates during the week, but not (or less frequently) on the weekend.

Specific changes:

• We more accurately recognize weekends. We previously had hardcoded support for Sat/Sun weekends. Now, we dynamically recognize weekends regardless of where they fall in the week (e.g. Fri/Sat, or when there’s just a single day “off”)
• Tighter thresholds in the “active” period of the week. About 5% of tables that we’re tracking have had their thresholds reduced by >25% from this change!
• Thoughtful thresholds in the “off” part of the week. So if the table doesn’t start back up on Monday, we’ll alert.

In the future, we’ll extend these improvements to “Time since last row count change”, and also add bimodality for day/night behaviors.