IN THIS CHAPTER
Extended Events packages and objects
Starting XE sessions
Querying XE data with XPath
If it ain't broke don't fix it.
In my humble opinion, there's nothing broken with SQL Trace and SQL Profiler, wait states, and DMVs. I've found these tools satisfactory for monitoring and diagnostics.
Nulltheless, the shiny new Extended Events (XE) feature, new in SQL Server 2008, is faster and more extensible than SQL Trace. SQL Trace has an easy UI: SQL Profiler. Extended Events has no (Microsoft provided) UI, and it has a steep learning curve. XE is also compatible with Event Tracing for Windows (ETW). You don't need to learn Extended Events to be successful with SQL Server 2008 today.
So why learn Extended Events? Two reasons. First, Extended Events is powerful and more granular than SQL Trace. Second, Extended Events is strategic to Microsoft. It's the foundation for event analysis going forward.
The core of Extended Events is the Extended Events engine, which can handle any event, and because the payload (the data about the event) is XML based, the engine can include different data for different events as appropriate.
The engine can see events synchronously, but can process events and send event data to the target (the consumer of the event data) synchronously or asynchronously, which is an improvement over SQL Trace and enables Extended Events to handle a greater load than SQL Trace.
SQL Server MVP and all-around smart guy, Jonathan Kehayias, ...