SQL Server Execution Plans - Red Gate Software

Chapter 1: Execution Plan Basics
• Showplan Statistics Profile – This event generates the actual execution plan in the
same way as the T-SQL command STATISTICS PROFILE. It still has all the shortcomings
of the text output, including only supplying a subset of the data available
to STATISTICS XML in T-SQL or the Showplan XML Statistics Profile event in SQL
Server Profiler. The Showplan Statistics Profile event is on the list for deprecation.
• Showplan XML – The event fires with each execution of a query and generates an
estimated execution plan in the same way as SHOWPLAN_XML. This is the event you
want in most cases. The others should be avoided because of the load they place on the
system or because they don't return data that is usable for our purposes.
• Showplan XML for Query Compile – Like Showplan XML above, but it only fires on a
compile of a given query.
• Performance Statistics – Similar to the Showplan XML For Query Compile event,
except this event captures performance metrics for the query as well as the plan. This
only captures XML output for certain event subclasses, defined with the event. It fires
the first time a plan is cached, compiled, recompiled, or removed from cache.
• Showplan XML Statistics Profile – This event will generate the actual execution plan
for each query, as it runs.
Capturing all of the execution plans, using Showplan XML or Showplan XML Statistics
Profile, inherently places a sizeable load on the server. These are not lightweight event
capture scenarios. Even the use of the less frequent Showplan XML for Query Compile
will cause a small performance hit. Use due diligence when running traces of this type
against any production machine.
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