This document discusses strategies for optimizing database performance through physical design and indexing. It begins by describing the journey of a transaction through the database and factors that can degrade performance. Various physical designs are proposed for different scenarios involving storage configuration, database file placement, and raid levels. The document also covers indexing strategies, including the types and organization of indexes, and how they support different data access patterns. Coding best practices are outlined such as maximizing index coverage and avoiding unnecessary sorting.

1. Indexing strategies and good physical
designs for performance tuning
Kenneth Ureña
http://www.sqlcr.com
@sqlcr
/SpanishPASSVC

2. Agenda
 The journey of a transaction
 Performance degradation factors
 Physical Designs
 Indexing
 Coding best practices

3. THE JOURNEY OF A TRANSACTION

4. Actual empty
Virtual
Log
File
Truncated
- Sequential Access
- Just 1 file Active
- Recommended
Raid 1 ó 1 + 0
- Commit, backup log
trigger I/O
- Random Access
- Multiple datafiles Active
- Recommended Raid 1/1+0
5+0 / 5
- Checkpoint, backup, load /
unload Cache
Full Empty Full Empty
Empty Full Empty Full

5. PERFORMANCE DEGRADATION
FACTORS

6. Hardware Software
DB Performance Degradation life cycle
Overload
Degraded PerformanceCPU / Memory
Storage
Peripheral
Database
Data
Algorithm

7. • Sata, SAS, SSD (Types of Hard Drives)
• Big performance difference between Sequential IO vs
Random IO
• IOPS (In Out Per Second)
• IOPS Estimated = 1 / ((seek time / 1000) + (latency / 1000))
Storage
Reference
http://www.cloudbyte.com/docs/Whitepaper_CloudByte_Measuring-Storage-Performance.pdf

8. • Average read seek time: 3.4 ms
• Average write seek time: 3.9 ms
• Average latency: 2.0 ms
• Seek time = (Average read seek time + Average write seek time) / 2
= (3.4 + 3.9) / 2 = 3.65 ms
• IOPS Estimated = 1 / ((seek time / 1000) + (latency / 1000))
= 1 / ((3.65/1000) + (2.0 / 1000)
= 176.9911 ~ 175 IOPS
SAS - 600GB 15K - Seagate
Reference
http://www.seagate.com/www/en-us/products/enterprise-hard-drives/cheetah-15k#tTabContentSpecifications

9. Raids
• Raid 0
• Raid 1
• Raid 5
• Raid 1 + 0

10. Raid 0 (Stripping)
 Logical Drive Characteristics
 IOPS = #Disk * IOPS Estimated
 Size = #Disks * Size disk
 Pros
 High performance
 Low cost
 Cons
 Fault tolerance
2
4
6
1
2
3
4
5
6
1
3
5
Raid 0
(Striping)
Disk1 Disk2
Logical
Drive

11. Raid 1 (Mirroring)
 Logical Drive Characteristics
 IOPS = (#Disk / 2) * IOPS Estimated
 Size = (#Disk / 2) * Size disk
 Pros
 Fault tolerance
 Cons
 Higher cost
1
2
3
4
5
6
Raid 1
(Mirror)
Disk1 Disk2
Logical
Drive
1
2
3
4
5
6
1
2
3
4
5
6

12. Raid 5
 Logical Drive Characteristics
 IOPS = (#Disk - 1) * IOPS Estimated
 Size = (#Disk - 1) * Size disk
 Pros
 Fault tolerance
 Cost Effective
 Cons
 Recalculation on raid failure
 Parity calculation
1
2
3
4
5
6
Disk2
Logical
Drive
Disk1
1
3
P
2
P
5
P
4
6
Raid 5
Disk3

13. 2
4
6
1
2
3
4
5
6
Disk3
Logical
Drive
2
4
6
Disk4
Raid 1Raid 1
Raid 0
1
3
5
Disk2
1
3
5
Disk1
Raid 1 + 0
 Logical Drive Characteristics
 IOPS = (#Disk /2) * IOPS Estimated
 Size = (#Disk / 2) * Size disk
 Pros
 Fault tolerance
 Cons
 Cost

14. Database Files
Random
Access
Multiple
Actives
Data
File Sequential
Access
One
Active
Log
File

15. PHYSICAL DESIGNS

16. Physical Designs
• Choosing the right Raid for the Database File
• Split the files in order to get the expected Access behavior

17. Scenario #1
• 1 User Database
• High OLTP Traffic
• High TempDB consumption
• 16 Cores Server

18. Scenario #1 (Proposal 1)
Raid 1+0 Drive
SAS
TempDB UserDB
Raid 5 Drive
SAS
Raid 1+0 Drive
SAS

19. Scenario #1 (Proposal 2)
Raid 1+0 Drive
SAS
TempDB UserDB
Raid 1+0 Drive
SAS
Raid 1+0 Drive
SAS

20. Scenario #1 (Proposal 3)
TempDB UserDB
Raid 1+0 Drive
SSD
Raid 1+0 Drive
SAS

21. Scenario #2
• multiple User Database
• High OLTP Traffic
• High TempDB consumption
• multiple Cores Server

22. Scenario #2 (Proposal 1)
Raid 1+0 Drive
SAS
TempDB
Raid 1+0 Drive
SAS
Raid 1+0 Drive
SAS
UserDBN
Raid 1+0 Drive
SAS
Raid 1 Drive
SSD
UserDB1

23. INDEXING

24. Indexes and OrganizationTable structure
Image from
SQL server 2008 books online

25. Indexes and OrganizationHeap Table
Image from:
SQL server 2008 books online

26. Indexes and OrganizationClustered Table
Image from:
SQL server 2008 books online

27. Clustered (example)
Image from:
http://www.sqlservercentral.com/images/4695.jpg

28. Indexes and OrganizationNonClustered
Index
Image from:
SQL server 2008 books online

29. Column Index
Image from
http://magenic.com/

30. Data access patters
 Seek
 Scan
 Bookmark Lookup

31. CODING BEST PRACTICES

32. Coding Best Practices
 Maximize coverage
 Avoid conversions (implicit/explicit)
 Avoid row by row access (cursor pattern)
 Avoid unnecessary sorting
 Choose the right index for the expected data
pattern access method

33. Q&A
Thank you
Kenneth Ureña
http://www.sqlcr.com
@sqlcr
/SpanishPASSVC