1. Query Profiling Options in SQL Server
Karol Papaj
Query Profiling Options in SQL Server

3. Karol Papaj SolidQ SQL Server BI SQL Server High Availability
SQL Server Relational Engine
@KarolPapaj

4. Execution plan with estimates
What’s Execution Plan
Instructions how to
perform a given query
Execution plan with estimates
how many rows each node
will have to process
Execution plan with
runtime statistics

5. Why we need Estimated Plan?
Performance troubleshooting (why is your query slow?)
Estimated
Serial? Parallel?
Seek? Scan?
Loop?Merge?Hash?
Serial? Parallel?
Seek? Scan?
Loop?Merge?Hash?

6. How Developer Can Get Estimated Plan
SET SHOWPLAN_TEXT
SET SHOWPLAN_XML
SET SHOWPLAN_ALL
Ctrl+L or “Display Estimated Execution Plan” in SSMS

7. How Developer Can Get Estimated Plan
Demo
How Developer Can Get Estimated Plan

8. Why we need Actual Plan?
Performance troubleshooting (why is your query slow?)
Actual
Duration? SQL Server 2014 SP2 and higher
Number of rows
Cardinality estimation error?
Missing filter condition
Outdated statistics
Memory used
Threads used
Degree of parallelism

9. How Developer Can Get Actual Plan
SET STATISTICS PROFILE
SET STATISTICS XML
Ctrl+K or “Include Actual Execution Plan” in SSMS

10. How Developer Can Get Actual Plan
Demo
How Developer Can Get Actual Plan

11. How DBA Can Get Estimated Plan?
Showplan XML event in Profiler
query_pre_execution_showplan in Extended Events
sys.dm_exec_cached_plans

12. How DBA Can Get Estimated Plan
Demo
How DBA Can Get Estimated Plan

13. How DBA Can Get Actual Plan?
Showplan XML Statistics Profile in Profiler
query_post_execution_showplan in Extended Events

14. How DBA Can Get Actual Plan
Demo
How DBA Can Get Actual Plan

16. 2
Problems

17. 1

18. Legacy profiling infrastructure CPU Overhead

19. Lightweight infrastructure
SQL Server 2016 SP1
query_thread_profile
extended event
DBCC TRACEON(7412,-1) GO
Enabled by
TF 7412

20. Lightweight infrastructure
Demo
Lightweight infrastructure

21. Profiling Infrastructure CPU Overhead
Source:

22. 2

23. query_thread_profile
QUERY_PLAN_PROFILE
SQL 2016 SP2 CU3
SQL 2017 CU11
SQL 2019
query_thread_profile
extended event
SELECT COUNT (*)
FROM Sales.SalesOrderHeaderEnlarged;
OPTION (USE HINT('QUERY_PLAN_PROFILE'));
QUERY_PLAN_PROFILE
hint

24. Demo
QUERY_PLAN_PROFILE

25. How to use QUERY_PLAN_PROFILE without touching a code
Query_ID
Profiling 1 2
Configuration table
Plan Guide

26. QUERY_PLAN_PROFILE Practical Usage
Demo
QUERY_PLAN_PROFILE Practical Usage

27. Be careful on getting Actual Execution Plan from production on SQL Server before 2014 SP2/2016
SQL 2014 SP2/2016 better
SQL 2016 SP1 much better
(enable lightweight infrastructure if CPU usage is < 95% on your server)
SQL Server 2019 has lightweight infrastructure enabled by default
SQL 2016 SP2 CU3/2017 CU11/2019 even better! (query_plan_profile_hint)

28. QUESTIONS ?
#SQLCLINIC

29. Resources MS SQL Tiger Team blog:
Execution Plan Reference by Hugo Kornelis:

30. THANK YOU !