Printed 2017/08/23 03:43PM

SQL Server : Index Part 2 : Structure of Heap Tables

By nelsonaloor, 2013/03/06

In the earlier post we tried to understand the difference between a table having clustered index and does not have a clustered index. A table with clustered index is called clustered table.A table with out clustered index is called a heap table.

Heap Table 
Each IAM pages store the allocation (single page and extent allocation) done for a single object. A table scan of a heap table can be performed by scanning the IAM pages to find the single pages and extents that are holding data pages of the heap.

To find out the IAM page, use the below command

DBCC IND('databasename','Tablename',-1)

In the output of the above query, record with value 10 for Page Type column are the IAM pages 

A typical heap structure is given below

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