Databases Reference
In-Depth Information
example, when a long I/O operation occurs, you might want to record the SQL Server statement to
which the event was related. All the information collected is sent to a
target
where it's stored. This
could be something as simple as a l at i le, but Extended Events also provides a few advanced storage
options that can process the collected data rather than just store it. Figure 13-1 provides an illustra-
tion of this basic process.
Event
Occurrence
Additional
Event Data
Event
Action
Target
Operating
System File
Simplified Extended Events Session
FIGURE 13-1
Where the Name Extended Events Comes From
Although the name Extended Events provides a clue as to what it's about, it is not as prescriptive as
something like Resource Governor. The Extended Events feature within SQL Server takes its name
partly from a high-performance troubleshooting feature in the Windows operating system called
Event Tracing for Windows (ETW), a low-level debugging tool that exposes kernel-level events
generated by applications or device drivers. It is normally used by developers during development
and troubleshooting. Some SQL Server tuning experts use it to obtain very detailed performance
data from Windows. ETW has been around since Windows Server 2000, and it introduced the
Windows kernel concepts of controllers, providers, and consumers of event data, terminology
that's still used today.
Rather than get very technical, it is sufi cient to know that the Extended Events feature was built on
the fundamental design principles of ETW, in terms of both its architectural design and its object-
naming conventions. The events it refers to are simply “things that happen” within your system,
such as a query being executed, a physical i le being read, or a memory request being granted —
similar to what you are used to seeing in Proi ler, but there are more of them, covering more areas.
Fortunately for us, SQL Server hides all this low-level complexity and just exposes objects and com-
mands that we can relate to as database professionals.
Search WWH ::
Custom Search