Online Statistics Gathering has been introduced in Oracle 12c. I think it is a very important building block to establish a consistent approach in dealing with optimizer statistics in your ETL jobs. I have already written some posts about it a while ago (first, second and third). When I was preparing a talk about optimizer statistics for data engineers recently, I took a closer look at it again. Oracle has now continuously improved the feature over several versions and has lifted many restrictions. Let’s see what I mean.