Getting To Know Your Indexes Microsoft SQL Server 2005/2008

Who Am I? Jason Strate SQL Server MVP Enterprise Consultant with Digineer Working with SQL Server since 1997 jstrate@digineer.com tinyurl.com/StrateSQL twitter.com/StrateSQL

Session Agenda Session Goals Index Basics System Views Index DMVs New Information

Session Agenda Session Goals Index Basics System Views Index DMVs New Information

Session Goals Identify methods to analyze current and potential indexes Learn how to identify stress found on indexes Demonstrate methods for tuning indexes Usage patterns Maintenance weight

Last Year on an Airplane… I Had Dream… What if… “I mix all index related DMVs with its metadata into a single query?”

I Hope So This Means Something… Will we learn something new about indexes and their relationships? I Hope So

Session Agenda Session Goals Index Basics System Views Index DMVs New Information

Index Basics Storage structure (B-Tree) associated with a table or view built from one or more columns (key values). The purpose of which is to improved data retrieval.

Index Basics Types Clustered – data rows stored with key values Non-Clustered – key values stored with pointer to data row Heap – unordered structure Vary with properties of Filtered, Included, Unique Out-of-scope: Full-Text, Spatial, XML

Session Agenda Session Goals Index Basics System Views Index DMVs New Information

Check Out The Indexes Methodology: Heaps or Clustered? Identical Indexes Overlapping Indexes Objects sys.indexes sys.index_columns sys.dm_db_partition_stats Unique, primary key,

Foreign Keys? Methodology Index your foreign key columns. Objects: sys.foreign_keys sys.foreign_key_columns

System Views DEMO

Session Agenda Session Goals Index Basics System Views Index DMVs New Information

Captain Obvious Methodology Keep the indexes that you use Objects sys.dm_db_index_usage_stats sys.dm_db_index_operational_stats

Captain Obvious, Again Methodology Build indexes that your queries will find useful Objects sys.dm_db_missing_index_details sys.dm_db_missing_index_groups sys.dm_db_missing_index_group_stats

Is It Money? Methodology Is it worth the maintenance? Objects sys.dm_db_index_operational_stats

Did I Just Say Maintenance? Methodology Tuning is better than troubleshooting Object sys.dm_db_index_physical_stats

Index DMVs DEMO

Are You Burning Disk? Methodology IO is resource intensive – are you managing it? Objects sys.dm_os_buffer_descriptors sys.allocation_units

Index DMVs DEMO

Session Agenda Session Goals Index Basics System Views Index DMVs New Information

Pull It Together Index Analysis System Views DMVs http://indexanalysis.codeplex.com/

Should I Create The Index? Scenario 2nd index on table 10th index on table 20th index on table Similarities It Depends

It Depends Should I Drop The Index? Scenario Index is hardly used. Maybe it’s used to determine your bonus What’s the risk? It Depends

Code Word: It Depends Get the information you need Table A and Table B have different needs Build a methodology around your databases Best practices are guidelines

Build A Methodology Analyze Add Monitor Remove

Remember Spend time getting to know your indexes regularly Data changes. Usage changes. So indexing needs change DMV statistics are based on maintenance and service start times

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for attending this session and the 2009 PASS Summit in Seattle Thank you for attending this session and the 2009 PASS Summit in Seattle