Here’s something odd. If you do an online search for “SQL Server latch promotion”, a number of top hits (e.g. this, this and this) don’t actually concern latch promotion, but rather an obscure informational message that seemed to come out of the woodwork in 2008 R2: Warning: Failure to calculate super-latch promotion threshold.”.
Somewhere among those hits you’ll find one of the very few sources around latch promotion, Bob Dorr’s excellent “How it works” blog post. One thing that bugs me about this picture is that latch promotion clearly isn’t that much talked about until people see unusual messages in their error logs.
Continue reading “The Latch Files 3: Superlatch promotion threshold”