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Clustered Index Space


Clustered Index Space

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SQLSACT
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Hi All

I understand that when you create a clustered index, SQL Server doesn't create a physical structure seperate from the table.

Initially I though that this can't be right because SQL allows you to create a table in one filegroup and then create the Clustered index in a different filegroup. I tested this and saw that when you create a Clustered index on a table in a different filegroup, SQL moves the table to the filegroup that contains the clustered index.

My question> Why is it that after creating a clustered index, the size of the table increases slightly? Is this perhaps the pages in the non-leaf levels of the B-Tree?

Thanks
anthony.green
anthony.green
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It needs somewhere to store the B-Tree so you would expect it to be slighltly larger after changing from a heap to a clustered index.



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anthony.green (2/13/2013)
It needs somewhere to store the B-Tree so you would expect it to be slighltly larger after changing from a heap to a clustered index.


Thanks Anthony

Would you agree that a Clustered Index is absolutely NOT a seperate structure from your table?

Thanks
anthony.green
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Yes I would aggree as the clustered index IS your table.



Want an answer fast? Try here
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When a question, really isn't a question - Jeff Smith
Need a string splitter, try this - Jeff Moden
How to post performance problems - Gail Shaw
CrossTabs-Part1 & Part2 - Jeff Moden
SQL Server Backup, Integrity Check, and Index and Statistics Maintenance - Ola Hallengren
Managing Transaction Logs - Gail Shaw
Troubleshooting SQL Server: A Guide for the Accidental DBA - Jonathan Kehayias and Ted Krueger


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anthony.green (2/13/2013)
Yes I would aggree as the clustered index IS your table.


Great Stuff - Thanks for your input
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