1. SQL Server Performance Tuning
Old-School Practical Guide
Denis Reznik
Data Architect at Intapp
Microsoft Data Platform MVP

2. Sponsors
Gold sponsors:
Silver sponsors:
Bronze sponsors:

3. About me Denis Reznik Kyiv, Ukraine Data Architect at Intapp
Microsoft Data Platform MVP
Co-Founder of Ukrainian Data Community Kyiv
Co-author of “SQL Server MVP Deep Dives 2”

4. Agenda
Data Collection
Data Analysis
Query Optimization
4 |

5. SQL Server Management Studio
Tools
SQL Profiler
Performance Monitor
SQL Server Management Studio

6. Indexes and Statistics
Quick Overview

7. Heap
1K .. 5K
12K .. 15K
22K .. 41K
7K .. 8K
51K .. 71K k
6K .. 7K
10K .. 11K
9K .. 10K
8K .. 9K
1M .. 2M
5K .. 6K
15K .. 21K
21K .. 22K
41K .. 51K
71K .. 1M
2M .. 3M

8. … … Clustered Index 1 .. 1M 1 .. 2K 2K+1 .. 4K 1M-2K .. 1M 1 .. 300
,5K
1,5K K …

9. … … Index Seek SELECT * FROM Users WHERE Id = 523 1 .. 1M 1 .. 2K
2K K
1M-2K .. 1M …
,5K
1,5K K …

10. … … Index Scan SELECT * FROM Users 1 .. 1M 1 .. 2K 2K+1 .. 4K
1M-2K .. 1M …
,5K
1,5K K …

11. … … Index Range Scan SELECT * FROM Users WHERE Id BETWEEN 700 AND 1700
1 .. 2K
2K K
1M-2K .. 1M …
,5K
1,5K K …

12. … … Non-Clustered Index Non-Clustered Index (Name) SELECT * FROM Users
A .. Z
SELECT * FROM Users
WHERE Name = 'John Dow'
A .. C
C .. K
X .. Z …
Clustered Index
(Id)
1 .. 1M
Heap
1 .. 2K
2K .. 4K
1M-2K .. 1M
1 .. 2K
2K K
1M-2K .. 1M …

13. Index Allocation Map (IAM)
Allocation Order Scan
Index Allocation Map (IAM)
Extent 1
Extent 2
Clustered Index (Id)
Extent N
1 .. 1M
Extent 1
Extent N
1 .. 2K
2K K
1M-2K .. 1M …

14. Statistics SELECT * FROM Users WHERE Id BETWEEN 2100 AND 2500
800
2000
2800
4500
5400

15. Parameter Sniffing and Dynamic SQL
Quick Overview

16. Parameter Sniffing - Stored Procedure
Query Processor
EXEC AnnualSalesReport
@UserId = 1
EXEC AnnualSalesReport
@UserId = 22
SQL Server Cache
Procedure cache
Procedure cache
Query executes using the query plan created for
@UserId = 1
Plan created and cached for the
@UserId = 1

17. Parameter Sniffing - Parametrized Query
Query Processor
sp_executesql N'SELECT * FROM Users WHERE Id int', 1
SELECT * FROM Users WHERE Id
SELECT * FROM Users WHERE Id
sp_executesql N'SELECT * FROM Users WHERE Id int', 22
SQL Server Cache
Procedure cache
Procedure cache
Plan created and cached for the
@Id = 1
Query executes using the query plan created for
@Id = 1

18. Dynamic SQL – Multiple Plans
Query Processor
SELECT * FROM Users WHERE Id = 1
SELECT * FROM Users WHERE Id = 22
SQL Server Cache
SELECT * FROM Users WHERE Id = 1
Procedure cache
Procedure cache
Procedure cache
Query executed using the query plan, created for the first query.
New query plan created and cached. Query executed using newly created plan.
New query plan again created and cached. Query executed using newly created plan.

19. Summary
Data Collection
Data Analysis
Query Optimization
19 |

20. Sponsors
Gold sponsors:
Silver sponsors:
Bronze sponsors:

21. Thank You!
Denis Reznik
@denisreznik