1. Performance Tuning for SQL Developers through Execution Plans
Vladimir Oselsky
Performance Tuning for SQL Developers through Execution Plans

2. About the Speaker Vladimir Oselsky (Vlady)
@VladyOselsky (Twitter), voselsky (LinkedIn)
Born and raised in Siberia (it does get cold, and sometimes hot)
B.S. Software Engineering Technology (I know some .NET)
Various IT Jobs since 1998.
Starting in 2010 worked with SQL Server and Oracle.

3. Execution Plans
Is an attempt of SQL Server optimizer to calculate the most optimal route to retrieve the data. Estimated Plan: Possible plan SQL Server will use when executing a query. Actual Plan: Actual plan SQL Server used when executing a query.

4. Execution Plan Graphical Text XML
Graphical representation of steps SQL Server took to execute the query. (Easy to Read)
Text
Textual representation of steps, containing details about every operation. (Hard to Read)
SHOWPLAN_ALL, SHOWPLAN_TEXT, STATISTICS PROFILE
XML
XML representation of steps outlined in structured way. (Maybe easy for some)

5. Plan Cache
Plan Cache – The place SQL Server stores actual and estimated plans.
Lazywriter – process that cleans up plans from Plan Cache based on age and complexity.
DBCC FREEPROCCACHE – command to clear plan cache (DO NOT RUN IN PROD)

6. Plan Basics
Button for displaying Estimated Execution Plan

7. Plan Basics Plans are read from RIGHT to LEFT.
Note: Mention extra time to run Query.

8. Plan Basics
To get more details need to hover over specific icons or view properties screen
Note: Mention extra time to run Query.

9. Plan Basics
To get more details need to hover over specific icons or view properties screen
Note: Mention extra time to run Query.

10. Plan Basics
Text plan.
Note: Mention extra time to run Query.

11. Plan Basics
STATISTICS IO – Outputs information related to execution to messages tab
Note: Mention extra time to run Query.

12. Plan Basics
STATISTICS TIME – Outputs information related to execution to messages tab
Note: Mention extra time to run Query.

13. Plan Basics
XML Plan – One options is to run SHOWPLAN_XML command or right click on Actual Plan and select Show PLAN XML Option
Note: Mention extra time to run Query.

14. XML Plan
Note: Mention extra time to run Query.

15. Stored Plans System views can used to retrieve stored plans – DEMO 01
SELECT [cp].[refcounts]
, [cp].[usecounts]
, [cp].[objtype]
, [st].[dbid]
, [st].[objectid]
, [st].[text]
, [qp].[query_plan]
FROM sys.dm_exec_cached_plans cp
CROSS APPLY sys.dm_exec_sql_text( cp.plan_handle ) st
CROSS APPLY sys.dm_exec_query_plan( cp.plan_handle ) qp;
Note: Mention extra time to run Query.

16. Plan vs Plan Estimated vs Actual may be different Stale Statistics
Estimated Plans are invalid - DEMO 02
Cost for Parallelism is reached
Note: Mention extra time to run Query.

17. Graphical Plan Explained
Reference Material for further reading
List of all operators for SQL Server 2008R2
List of all operators for SQL Server 2017
Note: Mention extra time to run Query.

18. Possible Problems Scan Operations
Note: Mention extra time to run Query.

19. Possible Problems Other performance hindering candidates
Note: Mention extra time to run Query.

20. Possible Problems Other performance hindering candidates
Note: Mention extra time to run Query.

21. Possible Problems Physical JOIN Operations – DEMO 03 HASH MERGE LOOP
Note: Mention extra time to run Query.

22. Possible Problems IMPLICIT CONVERSION – DEMO 04
Note: Mention extra time to run Query.

23. SentryOne Demo
Download:

24. Q&A Send questions to: vlady.oselsky@gmail.com
Blog:
Thank you

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