Index Fragmentation - SQL Server Query Performance Tuning - page 238

Figure 13-6. Page split caused by an UPDATE statement
From the preceding tables, you can see that the page split caused by the UPDATE statement results in an internal
fragmentation of data in the leaf pages. If the new leaf page can't be written physically next to the original leaf page,
there will be external fragmentation as well. For a large table with a high amount of fragmentation, a larger number of
leaf pages will be required to hold all the index rows.
Another way to look at the distribution of pages is to use some less thoroughly documented DBCC commands.
First up, you can look at the pages in the table using DBCC IND .
DBCC IND(AdventureWorks2012,'dbo.Test1',-1)
This command lists the pages that make up a table. You get an output like Figure 13-7 .