Didn't click your link so missed you were talking about my blog post.
I appreciate your interest in my blog post about Active Sessions, a topic I've devoted two decades to exploring. I rarely document my thoughts, but I recently put together the following post in a single evening. I acknowledge it could benefit from further refinement, so your feedback would be invaluable. If there are any aspects you believe need more elaboration or clarity, please don't hesitate to let me know.
A Comprehensive Guide to Understanding the AAS Metric in Databases
Their use of "sessions" is everywhere. AAS (average active session count) and all over the insights, including the activity bar. I'm just trying to map those back to exact things I can query myself from pg_stat_activity.
Just trying to get my head firmly around the RDS session number and associated performance/saturation. It says a session is any request waiting on a response from the server, so I am wondering if that's equivalent to selecting all from pg_stat_activity where state is active, and this would include all concurrent parallel workers, maintenance stuff, etc.
If you are referring to something in the RDS documentation or monitoring, could you provide a link to it, or an excerpt of it?