Downloaded 14 times
Uploaded byJason Strate
The Flavors of Non-Clustered Indexes
The document discusses non-clustered indexes in SQL Server, detailing their various types such as single column, multiple column, filtered, and included columns. It emphasizes the importance of using these different index types to enhance database performance and efficiency, especially for querying and accessing data. It also highlights best practices, such as avoiding excessive indexing and indexing foreign keys to minimize database issues.
More Related Content
Similar to The Flavors of Non-Clustered Indexes
The Flavors of Non-Clustered Indexes
- 1. The Flavors of Non-ClusteredIndexes
- 2. Introduction Jason Strate e: jstrate@pragmaticworks.com e: jasonstrate@gmail.com b:www.jasonstrate.com t: StrateSQL Resources jasonstrate.com/go/indexing MAKING BUSINESS INTELLIGENT www.pragmaticworks.com
- 3. About Pragmatic Works • • • • • • • Industryleaders in Microsoft BI and SQL Server Platform SQL Server Professionals - PASS Board of Directors, Speakers, Authors and MVP’s National Sales Team Divided by Microsoft Territories National System Integrator (NSI) Gold Certified in Business Intelligence and Data Platform Platform Modernization/Safe Passage Premier Partner for PDW SI Partner Program MS PDW Partner of Year FY13 Frontline Partnership Partner of the Year for Big Data Executive sponsor - Andy Mouacdie, WW sales director PDW • • Over 7,200 customers worldwide Over 186,000 people in PW database for demand generation MAKING BUSINESS INTELLIGENT www.pragmaticworks.com
- 4. Caution There will be lotsof ice cream pictures
- 5.
- 6.
- 7.
- 8.
- 9. Non-Clustered Indexes • Sortedkey values – One or more columns – Key values only – Pointers to Heap or Clustered Index rows – Non-LOB data • Secondary data access – Bridge to the data • Operations – Index scan – Index seek MAKING BUSINESS INTELLIGENT www.pragmaticworks.com
- 10. Agenda Vanilla Sundae Neapolitan Rocky Road Sugar Cone Gelato MAKINGBUSINESS INTELLIGENT www.pragmaticworks.com
- 11.
- 12. Single Column Index •Provides a secondary path to data • Allows alternative paths for finding data • One column is stored outside table – Data is sorted by key – Includes clustered index keys • Focus on most used columns for filters • Do not index every column MAKING BUSINESS INTELLIGENT www.pragmaticworks.com
- 13.
- 14.
- 15. Index Intersection • Leveragesmultiple non-clustered indexes • Filters on both indexes • Returns the “intersection” of both indexes Index 1 Index 2 MAKING BUSINESS INTELLIGENT www.pragmaticworks.com
- 16.
- 17.
- 18. Multiple Column Index •Two or more columns in the same index • Index sorted from left to right – Cannot skip columns to leverage sort • Cover filters over multiple columns – Or cover non-filtered columns • Reduces number of indexes needed MAKING BUSINESS INTELLIGENT www.pragmaticworks.com
- 19.
- 20.
- 21. Included Columns • • • • • Additional columnsneeded for queries Typically data not included in index Included columns brings in data pages Store specific columns unsorted with index Don’t included all columns – Or even most • Be cautious of update rate of data MAKING BUSINESS INTELLIGENT www.pragmaticworks.com
- 22.
- 23.
- 24. Filtered Indexes • Adda WHERE clause to your index • Changes the contents of the index – Reduction in pages – Reduction in size – Lessen impact of index scan • Unmatched Index warning MAKING BUSINESS INTELLIGENT www.pragmaticworks.com
- 25.
- 26.
- 27. Foreign Key Indexes •All foreign keys should be indexed – Not an index property • • • • Constraint leverages sorts on validation Can reduce locking, blocking, and deadlocks Common problem in many systems Silent killer of the database MAKING BUSINESS INTELLIGENT www.pragmaticworks.com
- 28.
- 29.
- 30. Summary • • • • You can getby on “vanilla” indexes Indexes can vary in flavors These flavors help improve your databases Filtered indexes, included columns, and multiple columns MAKING BUSINESS INTELLIGENT www.pragmaticworks.com
- 31. Learn More AboutIndexes MAKING BUSINESS INTELLIGENT www.pragmaticworks.com
- 32. For more information… Name:Jason Strate Email: jstrate@pragmaticworks.com Blog: www.jasonstrate.com Resource: jasonstrate.com/go/indexing Products BI products to covert to a Microsoft BI platform and simplify development on the platform. Services Speed development through training, and rapid development services from Pragmatic Works. Foundation Helping those who do not have the means to get into information technology achieve their dreams.