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Posted Wednesday, February 13, 2013 2:25 AM
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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
Post #1419353
Posted Wednesday, February 13, 2013 2:29 AM


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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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Post #1419354
Posted Wednesday, February 13, 2013 2:37 AM
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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
Post #1419355
Posted Wednesday, February 13, 2013 2:39 AM


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



Want an answer fast? Try here
How to post data/code for the best help - Jeff Moden
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

Post #1419356
Posted Wednesday, February 13, 2013 2:42 AM
Ten Centuries

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Last Login: Monday, October 6, 2014 7:17 AM
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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
Post #1419358
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