Press "Enter" to skip to content

Getting Wait Info From Extended Events

Grant Fritchey shows how to get wait information for particular sessions from the system_health extended event:

On your servers, any of them that are SQL Server 2008 or newer, right now, unless you’ve performed actions to prevent this, you’re running the Extended Events system_health session. It’s just happening, currently, on all your servers. Nothing you need to do about it at all. I’ll be a lot of you never even knew it was there.

If you follow the link you can see all the various types of information being gathered by the Extended Event system_health session. I won’t detail all of it here. Let me just provide a little context around how the session works. First and foremost, similar to the error log, this session consists of four files, each 5mb in size, rolling over as they get filled. For systems with a very high degree of activity, that means the information here may only be hours old. However, for most of us, this provides days, if not weeks worth of information about the behavior of your system.

The system_health extended event misses a lot of stuff, but it’s quite useful when you don’t have a purpose-built monitoring solution in place.