Tag: indexes

Index Fragmentation in SQL Server 2005

Index fragmentation is a phenomenon where the index contents are scattered. Normally the contents are in contiguous fashion which helps in fast retrieval of the underlying data. When the indexes are fragmented the data access becomes time consuming because of the scattered data that needs to be searched and read.

Moving Index to a separate Filegroup

To improve the query performance we decided to have separate filegroup for indexes. We decided to move the indexes of very large tables indexes to the new filegroup. Our intention was to separate the index from the data i.e. have the table data (Clustered index) in one filegroup and Nonclustered indexes in another separate filegroup […]

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

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 […]