1. Back to Indexes, the Original Culprit !
11/18/ :01 AM
DBI406
Back to Indexes, the Original Culprit !
Amit Bansal
CTO, eDominer Systems | Peopleware India
President & Founder,
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

2. Agenda Indexing Scenario The Holy Trinity: Optimizer + Indexes + DTA
TechEd 2012
11/18/ :01 AM
Agenda
Indexing Scenario
The Holy Trinity: Optimizer + Indexes + DTA
Back to the Scenario: Bad design vs Good design
Selectivity & Density: Does it make sense?
Summary
Image Source:
© 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

3. Agenda Demo: Indexing Scenario 1
TechEd 2012
11/18/ :01 AM
Agenda
Demo: Indexing Scenario 1
Optimizer’s choice of Physical Join Operator
Indexing Scenario 2
Demo: Good Design vs Better Design
The Optimizer’s choice of Indexes
Demo: Indexing Scenario 3
How, When & Why did the Indexes become culprits?
Demo: Clean up act !
Summary / Call to Action
© 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

4. demo Indexing Scenario 1 11/18/2018 11:01 AM
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

5. Optimizer’s choice of Physical Join Operator
TechEd 2012
11/18/ :01 AM
Optimizer’s choice of Physical Join Operator
NESTED LOOP JOIN
when the outer input is small and the inner input has an index on the join key
No restriction on operators; Inputs need not be sorted
MERGE JOIN:
Medium to large inputs
Requires equality operator & inputs must be sorted on join predicate
HASH JOIN:
Large inputs
Requires equality operator
© 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

6. Indexing Scenario 2 SELECT C.ContactID, C.FirstName, C.EmailPromotion
FROM Person.Contact2 AS C
WHERE C.FirstName LIKE N'L%'
AND C. Promotion = 1
AND C.ContactID < 10000
OPTION (MAXDOP 1)
--returns 77 out of records
4.3 % (872)
25.2 % (5044)
50.04 % (9994)

7. Indexing Scenario 2 4.3 % (872) 25.2 % (5044) 50.04 % (9994)
SELECT C.ContactID, C.FirstName, C. Promotion
FROM Person.Contact2 AS C
WHERE C.FirstName LIKE 'L%'
AND C. Promotion = 1
AND C.ContactID < 10000
OPTION (MAXDOP 1)
-- Option 1
CREATE INDEX ContactComposite4
ON Person.Contact2(FirstName, Promotion)
-- Option 2
CREATE INDEX ContactComposite5
ON Person.Contact2( Promotion, FirstName)
4.3 % (872)
25.2 % (5044)
50.04 % (9994)

8. Good Design vs Better Design
11/18/ :01 AM
demo
Good Design vs Better Design
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

9. The Optimizer’s choice of Indexes
TechEd 2012
11/18/ :01 AM
The Optimizer’s choice of Indexes
Single column index:
True:
FirstName LIKE 'L%'
Promotion = 1
ContactID < 10000
False:
FirstName LIKE ‘%L'
ABS( Promotion) = 1
ContactID + 1 < 10000
© 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

10. The Optimizer’s choice of Indexes
TechEd 2012
11/18/ :01 AM
The Optimizer’s choice of Indexes
Multi-column index:
The index can be used to seek on the second column if there is an equality predicate on the first column
True:
FirstName = ‘L‘ AND Promotion = 1
Partially True:
FirstName LIKE ‘L%‘ AND Promotion = 1
False
FirstName LIKE ‘%L‘ AND Promotion = 1
© 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

11. The Optimizer’s choice of Indexes
TechEd 2012
11/18/ :01 AM
The Optimizer’s choice of Indexes
Multi-column index: Our scenario
© 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

12. demo Indexing Scenario 3 11/18/2018 11:01 AM
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

13. How, When & Why did the indexes become culprits?
TechEd 2012
11/18/ :01 AM
How, When & Why did the indexes become culprits?
Too many Non-Clustered indexes?
Did you strike a right balance between SELECT & UPDATE performance?
Can you get rid of some redundant indexes?
Image source:
© 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

14. IO Statistics LA 0 LB 1 LC 0 LD 2 LE 0 LF 1 LG 0 LH 2 LI 0 LJ 1 LK 0
TechEd 2012
11/18/ :01 AM
IO Statistics LA LB LC LD LE LF LG LH LI LJ LK LM LN LO LP LQ LR LS LT LU LV LW LX LY LA LC LE LG LI LK LN LZ LA LF LJ LO
LOA
1 LOB
LOC
LOD LS LZ LA LH LM LQ LU LZ
© 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

15. IO Statistics LA 0 LB 1 LC 0 LD 2 LE 0 LF 1 LG 0 LH 2 LI 0 LJ 1 LK 0
TechEd 2012
11/18/ :01 AM
IO Statistics LA LB LC LD LE LF LG LH LI LJ LK LM LN LO LP LQ LR LS LT LU LA LC LE LG LI LK LN LP LB LF LJ LO LS LW LD LH LM LQ LU LY
© 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

16. 11/18/ :01 AM
demo
Clean up act !
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

17. Summary / Call to Action
TechEd 2012
11/18/ :01 AM
Summary / Call to Action
Browse this recording once again 
Try out the code snippets yourself
Review your indexing strategies
Implement the knowledge
Try out various combinations in your ‘test environment’
© 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

18.
Amit
Bansal
@A_Bansal

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23. 11/18/ :01 AM
© 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.
© 2009 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

24. 11/18/ :01 AM
© 2009 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.