Paul Randal re-continues a series:
In the first part of this series I introduced basic terminology around logging so I recommend you read that before continuing with this post. Everything else I’ll cover in the series requires knowing some of the architecture of the transaction log, so that’s what I’m going to discuss this time. Even if you’re not going to follow the series, some of the concepts I’m going to explain below are worth knowing for everyday tasks that DBAs handle in production.
Note: as I progress through this series and talk about aspects of the log, there are often little edge-cases or weird behaviors in niche circumstances that have been added or changed over the years. I’ll ignore those unless I specifically want to call them out, otherwise the posts would be riddled with rat-holes and mazes of twisty-turny little passages (yes, I loved ’80s text-based adventure games 🙂 that would distract from the main things to learn about in each post.
Click through for a primer on virtual log files, log blocks, and log sequence numbers.