Geo - Make schedulers responsible for initial backfill smart
Problem to solve
The Geo schedulers responsible for backfilling mechanism are responsible for the most expensive queries that Geo runs. Even with FDW enabled, we noticed that the performance could not be satisfactory for large instance like GitLab.com.
First, we need to make have 100% sure that our log cursor is reliable and we don't miss any event then we can make the schedulers smarter. They should stop themselves as soon as the initial backfill is complete.
To accomplish this we can check during the initial backfill only projects, uploads, job artifacts, etc that the id is lower than the first one seen by the log cursor.