The Curious Case of… eager writing and minimally-logged operations

(The Curious Case of… used to be part of our bi-weekly newsletter but we decided to make it a regular blog post instead so it can sometimes be more frequent. It covers something interesting one of us encountered when working with a client, doing some testing, or were asked in a random question from the community.)

I had an email discussion with someone last week who was wondering about log backups and minimally-logged operations. Specifically they were confused as to how the log backup works if no checkpoint has occurred since the operation completed. Surely the data pages are still dirty in memory?