Category: Performance Tunning

Index usage

I have used the Contact table with person schema which is residing in AdventureWorks database for testing the index usage. I am describing the scenarios and places where index seek or scan will be used.

Index with Included columns

Included column is a new feature in SQL Server 2005. When you add a column as an Included column, it gets stored at the leaf level of the index and it is not part of the index key. This only works for non-clustered indexes.


Indexes are used to speedup data access in the database. By using them one can quickly find the data in a table without having to read all the data from the tables. The index structure resembles an inverse tree similar to a directory structure. This tree begins with the 1st page of an index which […]

Filtered Index – SQL Server 2008

Introduction: Filtered index concept is new feature added from SQL Server 2008. A filtered index is an optimized nonclustered index, especially suited to cover queries that select from a well-defined subset of data. It uses a filter predicate to index a portion of rows in the table.